IF YOU CANNOT TURN OFF THE ELECTRICAL
POWER, PULL, PUSH, OR LIFT THE PERSON TO
SAFETY USING A WOODEN POLE OR A ROPE
OR SOME OTHER INSULATING MATERIAL
SEND FOR HELP AS SOON AS POSSIBLE
AFTER THE INJURED PERSON IS FREE OF
CON-TACT WITH THE SOURCE OF ELECTRICAL
B E C A R E F U L W H E N W O R K I N G W I T H A C L I N E C O N N E C T I O N S .
S E R I O U S I N J U R Y O R D E A T H M A Y R E S U L T F R O M C O N T A C T W I T H T E R M I N A L S .
DO NOT SERVICE OR ADJUST ALONE
Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.
SAFETY PRECAUTION
A periodic review of safety precautions in TB 385-4, Safety Precautions for Maintenance of Elec-t r i c a l / E l e c Elec-t r o n i c E q u i p m e n Elec-t , i s r e c o m m e n d e d . W h e n Elec-t h e e q u i p m e n Elec-t i s o p e r a Elec-t e d w i Elec-t h c o v e r s removed, DO NOT TOUCH exposed connections or components. MAKE CERTAIN you are not grounded when making connections or adjusting components inside the test instrument.
TRICHLOROTRIFLUOROETHANE
Adequate ventilation should be provided while using TRICHLOROTRIFLUOROETHANE. Prolonged breathing of vapor should be avoided. The solvent should not be used near heat or open flame; t h e p r o d u c t s o f d e c o m p o s i t i o n a r e t o x i c a n d i r r i t a t i n g . Since’ TRICHLOROTRIFLUOROETHANE dissolves natural oils, prolonged contact with skin should be avoided. When necessary, use gloves which the solvent cannot penetrate. If the solvent is taken internally, consult a physician i m m e d i a t e l y .
DIRECT SUPPORT AND GENERAL SUPPORT M A I N T E N A N C E M A N U A L POWER SUPPLIES PP-4763/GRC (NSN 5820-00-937-7690) AND PP-4763A/GRC (NSN 5820-00-113-9768)
REPORTING ERRORS AND RECOMMENDING lMPROVEMENTS
You can help improve this manual. If you find any mistakes or if you know of a way to improve the procedures, please let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms), or DA Form 2 0 2 8 - 2 l o c a t e d i n b a c k o f t h i s m a n u a l d i r e c t t o : C o m m a n d e r , U S A r m y Communications-Electronics Command and Fort Monmouth, ATTN: DRSEL-ME-MP, Fort Monmouth, New Jersey 07703. A reply will be furnished direct to you.
T A B L E O F C O N T E N T S C H A P T E R 1 S e c t i o n I S e c t i o n I I S e c t i o n I I I C H A P T E R 2 S e c t i o n I S e c t i o n I I S e c t i o n I I I S e c t i o n I V C H A P T E R 3 INTRODUCTION . . . . S e c t i o n I S e c t i o n I I S e c t i o n I I I S e c t i o n I V A P P E N D I X A P A G E 1-0 1-2 1-2 1-5 2 - 0 2-1 2 - 2 2 - 2 2 2 - 4 4 3-1 3 - 2 3 - 3 3 - 6 3 - 1 0 A-1
I N T R O D U C T I O N
S e c t i o n I . G E N E R A L I N F O R M A T I O N
P A G E Destruction of Army Materiel to Prevent Enemy Use . . . 1-2 Maintenance Forms, Records and Reports . . . 1-2 Reporting Equipment improvement Recommendations (ElR) . . . 1-2 Scope . . . 1-2 Technical Characteristics . . . 1-2
S e c t i o n I I . E Q U I P M E N T D E S C R I P T I O N A N D D A T A
Differences Between Models. . . 1-3 PowerSupplyConnectionsto Radio Set AN/GRC-106 . . . 1-4 Purpose and Use . . . 1-2 Safety, Care, and Handling . . . 1-4
S e c t i o n I I I . T E C H N I C A L P R I N C I P L E S O F O P E R A T I O N
Block Diagram Analysis . . . 1-5 Control Circuits . . . 1-8 Powerand Voltage Circuits. . . 1-6
The power supplies and their maior electronic components are described in section II of this chapter. Operating instructions and organizational maintenance are covered in TM 11-5820-765-12.
N O T E
I n t h i s m a n u a l , P o w e r S u p p l i e s P P 4 7 6 3 / G R C a n d P P 4 7 6 3 A / G R C a r e r e f e r -r e d t o a s p o w e -r s u p p l y ( * ) . S p e c i f i c m o d e l s a -r e i d e n t i f i e d b y u n i t n o m e n c l a t u r e , w i t h o u t t h e G R C d e s i g n a t i o n .
1-2. MAINTENANCE FORMS, RECORDS, AND REPORTS
Department of the Army forms and procedures used for equipment maintenance will be those prescribed by TM 38-750, The Army Maintenance Management System (TAMMS).
1-3. DESTRUCTION OF ARMY MATERIEL TO PREVENT ENEMY USE
D e s t r u c t i o n o f A r m y e l e c t r o n i c s m a t e r i e l t o p r e v e n t e n e m y u s e s h a l l b e i n a c c o r d a n c e w i t h T M 750-244-2.
1 - 4 . R E P O R T I N G E Q U I P M E N T I M P R O V E M E N T R E C O M M E N D A T I O N S ( E I R )
If your Power Supplies PP-4763/GRC and PP-4763A/GRC need improvement, let us know. Send us an EIR. You, the user, are the only one who can tell us what you don’t like about your equipment. Let us know why you don’t like the design. Put it on an SF 368 (Quality Deficiency Report). Mail it to Com-mander, US Army Communications-Electronics Command and Fort Monmouth, ATTN: DRSEL-ME-MP, Fort Monmouth, New Jersey 07703. We’ll send you a reply.
Item PP-4763 P P - 4 7 6 3 A A C p o w e r o p t i o n A C p o w e r c a b l e W 3 A C p o w e r s w i t c h C B 1 D C o u t p u t c o n n e c t i o n s T e r m i n a l b o a r d T B 1 R e a c t o r L 3 ( c h o k e ) T o p c o v e r i n t e r l o c k s w i t c h S1 T e s t j a c k s ( o n c i r c u i t c a r d a s s e m b l y ) 1 1 5 v o l t s a c , P r o v i d e d w i t h t e r m i n a l l u g f o r e a c h w i r e c o n n e c t i o n t o a c p o w e r s o u r c e . S i n g l e s w i t c h c i r c u i t b r e a k e r . T e r m i n a l b o a r d A 8 - c a b l e a t t a c h e d t o c o n n e c t d c o u t p u t t o e q u i p m e n t u n d e r t e s t . P r o v i d e s c o n n e c t i o n s f o r t r a n s f o r m e r T 1 . N o t p r o v i d e d N o t p r o v i d e d N o t p r o v i d e d 115 or 230 volts ac, 63 Hz. P r o v i d e d w i t h l o c k i n g p r o n g s o n p l u g f o r c o n n e c t i o n t o a c p o w e r s o u r c e . D o u b l e s w i t c h c i r c u i t b r e a k e r . C a b l e f r o m e q u i p m e n t u n d e r t e s t c o n n e c t e d e i t h e r t o t e r m i n a l b o a r d A 8 o r t o r e c e p t a c l e J 1 . P r o v i d e s c o n n e c t i o n s f o r t r a n s f o r m e r T 1 a n d f o r 1 1 5 -v o l t a c / 2 3 0 - -v o l t a c I i n k s . P r o v i d e d P r o v i d e d ; d i s c o n n e c t s a c i n p u t p o w e r w h e n t o p c o v e r i s r e m o v e d . T e s t j a c k s T P 1 t h r o u g h T P 6 p r o v i d e d .
Differences Between Reference Designations
M o s t p a r t s u s e d i n b o t h p o w e r s u p p l i e s h a v e o n e r e f e r e n c e d e s i g n a t i o n . E X A M P L E : V o l t m e t e r i s d e s i g n a t e d M l i n b o t h p o w e r s u p p l i e s . T h e f o l l o w i n g p a r t s h a v e d i f f e r e n t r e f e r e n c e d e s i g n a t i o n s : P P - 4 7 6 3 P P - 4 7 6 3 A C i r c u i t c a r d a s s e m b l y P C 1 0 1 A 1 R e c t i f i e r b r i d g e z N o d e s i g n a t i o n ( o n c i r c u i t c a r d a s s e m b l y ) R F I f i l t e r F L z S i l i c o n c o n t r o l l e d r e c t i f i e r S C R Q F o r t h e s e p a r t s , p a r e n t h e s e s i n d i c a t e d e s i g n a t i o n s f o r P P - 4 7 6 3 A .
1-9.
pounds. When packed for shipment, each unit weighs about 200 pounds. Use four persons to remove unit from shelter.
Carry by both handles at all times.
T h e b l o c k d i a g r a m d e s c r i b e s t h e p o w e r s u p -p l y ’ s m a j o r e l e c t r o n i c c o m -p o n e n t s a n d c i r c u i t s .
The power supply requires an input of 115
volts ac or 230 volts ac for operation, and has an o u t p u t o f 2 7 - 2 9 v o l t s d c . I n p u t p o w e r : A p p l i e d t h r o u g h a r a d i o f r e q u e n -c y i n t e r f e r e n -c e ( R F I ) f i l t e r t o t h e -c i r -c u i t b r e a k e r . W i t h t h e c i r c u i t b r e a k e r c l o s e d ( P O W E R O N ) , i n p u t p o w e r f l o w s t o t h e p o w e r t r a n s f o r m e r , w h i c h f e e d s t h e f a n m o t o r , c i r c u i t c a r d a s s e m b l y , a n d a l l o f t h e p o w e r s u p p l y ’ s c i r c u i t s . O u t p u t : T h e t r a n s f o r m e r a p p l i e s p o w e r t h r o u g h a r e a c t o r t o a f u l l - w a v e b r i d g e r e c t i f i e r , w h i c h c o n v e r t s t h e i n p u t f l o w t o d c . A s i l i c o n c o n t r o l l e d r e c t i f i e r r e g u l a t e s t h e d c o u t p u t ; c o n t r o l c i r c u i t r y i n t h e c i r c u i t c a r d a s s e m b l y p r o -v i d e s a u t o m a t i c , c o n t i n u o u s -v o l t a g e r e g u l a t i o n . A f i l t e r n e t w o r k p u r i f i e s t h e d c s i g n a l ; t h e r e g u l a t e d p o s i t i v e d c o u t p u t f l o w s t h r o u g h t h e o u t p u t c u r r e n t m e t e r ( a m m e t e r ) a n d i s s h u n t t o t h e d c o u t p u t t e r m i n a l . A v o l t a g e a d j u s t c i r c u i t p e r m i t s m a n u a l a d j u s t m e n t o f t h e o u t p u t v o l t a g e ; c o n t r o l s i n t h e c i r -c u i t -c a r d a s s e m b l y s e n s e t h e a d j u s t m e n t a n d c h a n g e t h e v o l t a g e . A n o v e r v o l t a g e c i r c u i t , a c t i v a t e d w h e n n e e d e d , a p p l i e s a s h o r t c i r c u i t l o a d t o t h e o u t p u t t e r m i n a l s , o p e n i n g t h e c i r c u i t b r e a k e r . T h i s p r o
-tects the power supply and the equipment being p o w e r e d .
T h e o u t p u t v o l t a g e m e t e r ( v o l t m e t e r ) m o n i t o r s o u t p u t v o l t a g e , w h i c h p a s s e s a g a i n t h r o u g h t h e R F I f i l t e r b e f o r e r e a c h i n g t h e d c o u t p u t t e r m i n a l .
P r o t e c t s a g a i n s t o v e r l o a d i n g p o w e r s u p p l y .
P o w e r O N : C o n n e c t s 1 1 5 - v o l t a c s o u r c e t o p r i m a r y w i n d i n g , p o w e r t r a n s f o r m e r T - 1 , a n d t o f a n m o t o r B 1 .
P P - 4 7 6 3 A
C I R C U I T B R E A K E R C B 1 ( r e f e r t o F O - 3 ) : Dual ac power switch.
T u r n s p o w e r s u p p l y O N , O F F . I n s e r i e s w i t h b o t h l e g s o f a c i n p u t p o w e r . P o w e r O N : C o n n e c t s e i t h e r 1 1 5 - o r 2 3 0 - v o l t a c s o u r c e t o p r i m a r y w i n d i n g , p o w e r t r a n s f o r m e r T 1 , a n d t o f a n m o t o r B 1 . S A F E T Y I N T E R L O C K S W I T C H S 1 : O p e n s i n p u t p o w e r c i r c u i t w h e n u n i t ’ s t o p p a n e l i s r e m o v e d . This is a protective control.
Functional Analysis of Power Circuit Parts
T R A N S F O R M E R T 1 : S e c o n d a r y w i n d i n g :
P o w e r s e c o n d a r y s u p p l i e s f u l l - w a v e b r i d g e r e c t i f i e r (rectifier diodes CR1, CR2, CR3, and CR4).
T w o c o n t r o l s e c o n d a r i e s s u p p l y c i r c u i t c a r d a s s e m b l y P C 1 0 1 ( A l ) . S I L I C O N C O N T R O L L E D R E C T I F I E R S C R 1 ( Q 1 ) :
Connected in bridge rectifier outlet. Regulates dc output.
R E A C T O R L 2 :
Connected in ac supply to bridge rectifier.
VOLTAGE REGULATION CIRCUIT B u i l t i n t o c i r c u i t c a r d a s s e m b l y P C 1 0 1 ( A 1 ) . C o n t r o l s f i r i n g t i m e o f s i l i c o n c o n t r o l l e d r e c t i f i e r S C R 1 ( Q 1 ) . K e e p s d c v o l t a g e a t a d j u s t e d s e t t i n g . E X P L A N A T I O N : S C R 1 ( Q 1 ) f i r e s t w i c e e a c h c y c l e o f a c i n p u t v o l t a g e . B y c o n t r o l l i n g f i r i n g t i m e , S C R 1 ( Q 1 ) c a n b e v a r i e d f r o m f u l l o n w h e n f i r e d a t s t a r t o f e a c h h a l f - c y c l e t o f u l l o f f w h e n f i r e d a t e n d o f h a l f - c y c l e . B r i d g e r e c t i f i e r ’ s d c o u t p u t v o l t a g e c a n t h u s b e v a r i e d f r o m m a x i m u m p o s s i b l e v o l t a g e t o z e r o . OVERVOLTAGE CIRCUIT C I R C U I T P A R T S : S i l i c o n c o n t r o l l e d r e c t i f i e r S C R 2 ( Q 2 ) . L o w - r e s i s t a n c e r e s i s t o r R 3 . P r o t e c t s e q u i p m e n t b e i n g p o w e r e d f r o m o v e r v o l t a g e s . A c t i v a t e d w h e n m a l f u n c t i o n c a u s e s r i s e i n o u t p u t v o l t a g e . A C T I O N :
Circuitry in PC101 (A1) senses trouble, fires SCR2 (Q2). R E S U L T S :
F i r i n g a p p l i e s s h o r t - c i r c u i t l o a d t o o u t p u t t e r m i n a l s w h i c h r e d u c e s o u t p u t v o l t a g e t o v e r y l o w v a l u e .
Short-circuit load opens circuit breaker CB1, which turns power supply OFF. This prevents possible damage to power supply and equipment being pawered.
VOLTAGE ADJUST CIRCUIT (DC OUTPUT)
C I R C U I T P A R T S : V a r i a b l e d c v o l t a g e a d j u s t r e s i s t o r s R 4 , R 8 . Stabilizing capacitor C3. Fixed resistor R11. C O N N E C T I O N : D o o u t p u t v o l t a g e f e d t h r o u g h r e s i s t o r s t o P C 1 0 1 ( A 1 ) . V O L T A G E P A T H :
Do output negative (–) terminal to PC101 (A1). A d j u s t s p o w e r s u p p l y ’ s d c o u t p u t v o l t a g e . A c t i v a t e d w h e n d c o u t p u t v o l t a g e c h a n g e s .
R E S I S T O R F U N C T I O N S : R 4 a d j u s t s o u t p u t v o l t a g e .
R8 adjusts voltage range.
1 - 1 2 . C O N T R O L C I R C U I T S C I R C U I T C A R D A S S E M B L Y P C 1 0 1 ( A 1 ) : C o n t r o l s p o w e r s u p p l y o p e r a t i o n . S e n s e s v o l t a g e c h a n g e s i n a c i n p u t , d c o u t p u t c i r c u i t s . C o n t r o l s o p e r a t i o n o f v o l t a g e r e g u l a t i o n , o v e r v o l t a g e c i r c u i t s . D e r i v e s p o w e r f r o m t w o s e c o n d a r y w i n d i n g s o n t r a n s f o r m e r T 1 .
VOLTAGE REGULATION CONTROL
P C 1 0 1 ( A 1 ) C O N N E C T S T O : S i l i c o n c o n t r o l l e d r e c t i f i e r S C R 1 ( Q 1 ) . P o w e r s u p p l y ’ s f i n a l d c o u t p u t v o l t a g e . N O T E S C R 1 ( Q 1 ) r e g u l a t e s d c o u t p u t v o l t a g e . A C T I O N :
PC101 (A1) applies signal to SCR1 (Q1) gate.
S C R 1 ( Q 1 ) f i r e s , c o n d u c t s c u r r e n t a f t e r r e c e i v i n g s i g n a l . T i m i n g o f c o n t r o l g a t e s i g n a l a p p e a r s o n g a t e .
T I M I N G :
T i m i n g o f c o n t r o l g a t e s i g n a l d e p e n d s o n v a l u e o f o u t p u t v o l t a g e f e d t o P C 1 0 1 ( A 1 ) . I F : D o o u t p u t v o l t a g e i n c r e a s e s
PP-4763 Rectifier bridge Z 102.
PP-4763A Individual divides CR18, CR19, CR20, CR21. DC OUTPUT Z108 (CR18-CR21):
F I L T E R :
Resistor-capasitor filter circuit R102(R2); C103(C3); R103(R3); C104(C4). R E G U L A T O R : Resistor R105(R5) Zener diodes CR109(CR9); CR110(CR10). P L U S - M I N U S 2 0 - V O L T S U P P L Y C I R C U I T : C o m m o n p o i n t c o n n e c t s t o p o w e r s u p p l y ’ s p o s i t i v e o u t p u t . P L U S 2 0 - V O L T C I R C U I T : S u p p l i e s r e f e r e n c e d i o d e C R 1 0 4 ( C R 4 ) t h r o u g h r e s i s t o r R 1 1 3 ( R 1 3 ) . O u t p u t o f C R 1 0 4 ( C R 4 ) p r o v i d e s b i a s c u r r e n t t o b a s e o f t r a n s i s t o r Q 1 0 3 ( Q 3 ) . M I N U S 2 0 - V O L T C I R C U I T : S u p p l i e s v o l t a g e d i v i d e r R 1 0 7 ( R 7 ) , R 1 1 5 ( R 1 5 ) , t r a n s m i t t e r - r e s i s t o r c i r c u i t Q 1 0 3 ( Q 3 ) , R117(R17).
Second Power Supply to PC101(A1)
S O U R C E : Transformer T1, windings TB1-11, TB1-10. C u r r e n t p a s s e s t h r o u g h c u r r e n t - l i m i t i n g r e s i s t o r s R 6 , R 7 . R E C T I F I E R B R I D G E C I R C U I T : PP-4763 - Rectifier bridge Z101. PP-4763A - Diodes CR14, CR15, CR16, CR17. P U L S A T I N G D C O U T P U T , Z 1 0 1 ( C R 1 4 - C R 1 7 ) :
Clipped by Zener diode CR109(CR9) through blocking diode CR105(CR5). Circuit output supplies:
R e s i s t o r - u n i j u n c t i o n t r a n s i s t o r c i r c u i t R 1 0 8 ( R 8 ) , R 1 0 9 ( R 9 ) , Q 1 0 1 ( Q 1 ) . Resistor-transistor circuit R1 11(R11), R112(R12), Q102(Q2). P O W E R S U P P L Y ’ S O U T P U T V O L T A G E : A p p l i e d t h r o u g h f r o n t p a n e l m o u n t e d a d j u s t m e n t a s s e m b l y A 4 A 2 A 1 R 1 1 , A 4 A 2 R 4 a n d A 4 A 2 R 8 , t h r o u g h r e s i s t o r R 1 2 0 ( R 2 0 ) , t o b a s e o f t r a n s i s t o r Q 1 0 3 ( Q 3 ) . B a s e c u r r e n t Q 1 0 3 ( Q 3 ) c r e a t e s c u r r e n t t h r o u g h R 1 1 7 ( R 1 7 ) . C u r r e n t c r e a t e s b i a s v o l t a g e f o r b a s e o f Q 1 0 2 ( Q 2 ) . T h i s c r e a t e s c u r r e n t f l o w t h r o u g h r e s i s t o r s R 1 1 1 ( R 1 1 ) , R 1 1 2 ( R 1 2 ) . T h i s s u p p l i e s c a p a c i t o r C 1 0 5 ( C 5 ) .
C l i p p e d p u l s a t i n g v o l t a g e t o u n i j u n c t i o n t r a n s i s t o r Q 1 0 1 ( Q 1 ) a l s o b e c o m e s z e r o a t t h i s i n s -t a n -t . V o l t a g e t o v o l t a g e d i v i d e r R 1 0 8 , R 1 0 9 ( R 8 , R 9 ) b u i l d s t o m a x i m u m v a l u e i n a p p r o x i m a t e l y 0 . 3 m i l l i s e c o n d . V o l t a g e t o b a s e 2 - b a s e 1 c i r c u i t o f Q 1 0 1 ( Q 1 ) b u i l d s t o m a x i m u m v a l u e i n 0 . 3 m i l l i s e c o n d . V o l t a g e t o e m i t t e r Q 1 0 1 ( Q 1 ) b u i l d s s l o w l y , d u e t o c h a r g i n g t i m e o f c a p a c i t o r C 1 0 5 ( C 5 ) . Emitter-base 1 resistance decreases, which connects C105(C5) to:
r e s i s t o r R 1 0 9 ( R 9 ) ,
g a t e o f c o n t r o l l e d r e c t i f i e r S C R 1 0 1 ( Q 6 ) . SC R101(Q6) turns on.
C o n n e c t s o u t p u t o f r e c t i f i e r b r i d g e Z 1 0 2 ( C R 1 8 t h r o u g h C R 2 1 ) t o g a t e o f S C R 1 ( Q 1 ) . SC R1(Q1) turns on.
Results of Voltage Changes
A c t i o n d e s c r i b e d a b o v e o c c u r s t w i c e p e r c y c l e ( 1 2 0 t i m e s / s e c o n d w i t h 6 0 H z i n p u t ) . SC R1(Q1) is fired at same instant of each cycle.
I F : O u t p u t v o l t a g e c h a n g e s ( d u e t o c h a n g e i n a c i n p u t v o l t a g e o r d c o u t p u t v o l t a g e ) . T H E N : B a s e c u r r e n t o f t r a n s i s t o r Q 1 0 3 ( Q 3 ) c h a n g e s . W H I C H : C h a n g e s c u r r e n t t h r o u g h R 1 1 7 ( R 1 7 ) . W H I C H : C h a n g e s b a s e v o l t a g e o f t r a n s i s t o r Q 1 0 2 ( Q 2 ) . I F : O u t p u t v o l t a g e i n c r e a s e s . T H E N : B a s e v o l t a g e o f Q 1 0 2 ( Q 2 ) i n c r e a s e s . W H I C H : I n c r e a s e s c u r r e n t t h r o u g h R 1 1 1 ( R 1 1 ) . W H I C H : R e d u c e s c h a r g i n g c u r r e n t i n t o c a p a c i t o r C 1 0 5 ( C 5 ) . W H I C H : D e l a y s f i r i n g t i m e o f u n i j u n c t i o n t r a n s i s t o r Q 1 0 1 ( Q 1 ) . W H I C H : D e l a y s f i r i n g o f S C R 1 ( Q 1 ) .
V o l t a g e r i s e s a b o v e p r e s c r i b e d v a l u e . Signal applied to gate of SCR2 (Q2). SCR2 (Q2) conducts.
Shorts output.
Opens circuit breaker CB1.
CONTROL CIRCUIT
V O L T A G E D I V I D E R :
Resistors R121, R122, R123 (R21, R22, R23). Connected across dc output terminals. R E G U L A T O R D I O D E C I R C U I T : Regulator diode CR106 (CR6). Resistor R124 (R24). Transistor Q104 (Q4). S u p p l i e s g a t e o f s i l i c o n c o n t r o l l e d r e c t i f i e r S C R 2 ( Q 2 ) t h r o u g h l i m i t i n g r e s i s t o r R 1 2 5 ( R 2 5 ) . T R A N S I S T O R Q 1 0 4 ( Q 4 ) : C o m p a r e s p o r t i o n o f o u t p u t v o l t a g e w i t h v o l t a g e o f C R 1 0 6 ( C R 6 ) . N O T E P o r t i o n o f v o l t a g e c o m p a r e d d e p e n d s o n s e t t i n g o f v a r i a b l e r e s i s t o r R 1 2 3 (R23). I F : O u t p u t v o l t a g e r i s e s a b o v e p r e s e t v a l u e . T H E N : Q 1 0 4 ( Q 4 ) c o n d u c t s . W H I C H : F i r e s S C R 2 ( Q 2 ) . W H I C H : O p e n s c i r c u i t b r e a k e r C B 1 . C A P A C I T O R C 1 0 8 ( C 8 ) : Stabilizes operation.
S e c t i o n I I . T R O U B L E S H O O T I N G
Adjusting Voltage Control Circuits . . . . Component Testing . . . . Procedures . . . . Symptom Index . . . . Testing and Troubleshooting Circuit Card Assembly PC101(A1) . . . . Troubleshooting Chart . . . . Voltage and Resistance Data.. . . .
S e c t i o n I I I . M A I N T E N A N C E P R O C E D U R E S
Removing and Replacing Panels . . . . Removing and Replacing Parts: . . . . AC cable plug W3P1 . . . . AC cable W3 . . . . AC input links . . . . Ammeter Ma . . . . Capacitors C1, C2 . . . . Circuit breaker CB1 . . . . Circuit card assembly PC101(A1) . . . . D C v o l t a g e a d j u s t c o m p o n e n t s R 4 , R 8 , R 1 1 , Diodes CR1-CR5 . . . . Diode CR6 . . . . Diode SCR1 (Q1) . . . . Diode SCR2 (Q2) . . . . FanmotorBl . . . . Interlock switch . . . . Reactor L2 . . . . 2-1 2-1 2 - 2 0 2 - 1 4 2 - 2 2 - 3 2 - 1 6 2 - 4 2 - 1 8 2 - 2 2 2 - 2 6 2 - 3 9 2 - 3 9 2 - 2 6 2 - 2 9 2 - 3 5 2 - 2 7 2 - 2 6 2 - 3 0 2 - 3 2 2 - 4 2 2 - 3 7 2 - 3 8 2 - 4 0 2 - 4 3 2 - 3 4
2 - 1 . G E N E R A L
L o w v o l t a g e , h i g h a m p e r a g e c u r r e n t i s p r e s e n t a t o u t p u t c o n -n e c t i o -n s a -n d c o -n -n e c t i o -n s i -n s i d e e q u i p m e -n t .
Shut off power supply before performing mointenonce.
B e c a r e f u l w h e n w o r k i n g w i t h 1 1 5 o r 2 3 0 v o l t a c l i n e c o n n e c -t i o n s .
S e r i o u s i n j u r y o r d e a t h m a y r e s u l t f r o m c o n t a c t w i t h t e r m i n a l s .
T h i s c h a p t e r c o v e r s d i r e c t s u p p o r t t r o u b l e s h o o t i n g , m a i n t e n a n c e , a n d t e s t i n g p r o c e d u r e s f o r the power supply. Section I lists the tools, test equipment, and materials needed to perform
d i r e c t s u p p o r t m a i n t e n a n c e . T r o u b l e s h o o t i n g p r o c e d u r e s a r e d e s c r i b e d i n S e c t i o n I I , m a i n t e n a n c e p r o c e d u r e s i n S e c t i o n I I I , a n d t e s t p r o c e d u r e s i n S e c t i o n I V .
2-2. REPAIR PARTS, TOOLS, TEST EQUIPMENT, AND MATERIALS
Repair Parts: Refer to TM 11-5820-765-34P-1. S p e c i a l T o o l s : N o s p e c i a l t o o l s a r e n e e d e d . T o o l s , T e s t E q u i p m e n t , a n d M a t e r i a l s :
I T E M National Stock Number
T O O L S T o o l K i t , E l e c t r o n i c E q u i p m e n t T K - 1 0 0 / G 5 1 8 0 - 0 0 - 6 0 5 - 0 0 7 9 T o o l K i t , E l e c t r o n i c E q u i p m e n t T K - 1 0 5 / G 5 1 8 0 - 0 0 - 6 1 0 - 8 1 7 7 T o r q u e W r e n c h , 1 5 0 i n c h - p o u n d s 5 1 2 0 - 0 0 - 2 3 0 - 6 3 8 0 TEST EQUIPMENT M u l t i m e t e r T S - 3 5 2 B / U 6 6 2 5 - 0 0 - 5 5 3 - 0 1 4 2 T r a n s f o r m e r , V a r i a b l e P o w e r T F - 1 7 1 / U S M 6 1 2 0 - 0 0 - 5 0 3 - 0 6 3 2 V o l t m e t e r , E l e c t r o n i c A N / U S M - 9 8 A 6 6 2 5 - 0 0 - 7 5 3 - 2 1 1 5 V o l t m e t e r , E l e c t r o n i c M E - 3 0 ( * ) / U 6 6 2 5 - 0 0 - 6 4 3 - 1 6 7 0 M A T E R I A L S T e s t S w i t c h , S i n g l e - P o l e ( 6 0 - a m p e r e ) R e s i s t o r , 0 . 5 6 o h m , 1 0 0 0 w a t t s R e s i s t o r , 1 . 3 o h m s , 1 0 0 0 w a t t s 5 9 0 5 - 0 0 - 0 6 4 - 4 6 7 9
L o c a l i z a t i o n m e a n s t r a c i n g t h e f a u l t t o a d e f e c t i v e c i r c u i t o r a s s e m b l y . I s o l a t i o n m e a n s p i n p o i n t i n g t h e s p e c i f i c p a r t c a u s i n g t r o u b l e . P r o c e d u r e s S E N S E t h e t r o u b l e : C h e c k m e t e r r e a d i n g s a n d o t h e r v i s u a l s i g n s t o l o c a l i z e t r o u b l e ; C h e c k f o r d i r t , d u s t , o r m o i s t u r e ; S m e l l f o r b u r n e d - o u t r e s i s t o r s a n d o t h e r p a r t s ; L i s t e n f o r a r c i n g t r a n s f o r m e r o r r e a c t o r s ; C h e c k f o r l o o s e s c r e w s a n d n u t s . Y o u c a n l o c a l i z e a n d i s o l a t e t r o u b l e t h i s w a y a n d r e d u c e r e p a i r t i m e . O P E R A T E t h e u n i t : A n o p e r a t i o n a l t e s t c a n o f t e n h e l p i s o l a t e t h e e x a c t c a u s e o f t r o u b l e . U S E t h e C H A R T : T h e t r o u b l e s h o o t i n g c h a r t l i s t s c o m m o n s y m p t o m s , t r o u b l e s a n d c o r r e c t i v e m e a s u r e s . N o t a l l t r o u b l e s y m p t o m s a r e l i s t e d i n t h e c h a r t , s o u s e i t a s a g u i d e f o r a n a l y z i n g s y m p t o m s n o t l i s t e d . C O M P O N E N T T E S T I N G : P a r a g r a p h 2 - 6 . T e s t s f o r d e f e c t i v e d i o d e s , m e t e r s , c o n t r o l l e d r e c t i f i e r s . U s e w i t h t r o u b l e s h o o t i n g c h a r t . U s e t o i s o l a t e d e f e c t i v e p a r t . T E S T I N G , T R O U B L E S H O O T I N G C I R C U I T C A R D A S S E M B L Y : P a r a g r a p h 2 - 7 . V O L T A G E , R E S I S T A N C E D A T A :
S y m p t o m P O W E R O N : V O L T M E T E R S H O W S Z E R O V O L T A G E ; F A N M O T O R B 1 D O E S N ’ T S T A R T . P O W E R O N : V O L T M E T E R S H O W S L O W O R Z E R O V O L T A G E ; F A N D O E S N ’ T S T A R T O R R U N S S L O W ; C I R C U I T B R E A K E R M A Y O R M A Y N O T T R I P . P O W E R O N : V O L T M E T E R S H O W S Z E R O V O L T A G E ; 2 7 V O L T S D C A T O U T P U T C O N N E C T I O N S . P O W E R O N : V O L T M E T E R M l S H O W S O U T P U T V O L T A G E ; F A N M O T O R B 1 D O E S N ’ T S T A R T . F A N M O T O R B 1 O P E R A T E S ; V O L T -M E T E R -M l , A -M -M E T E R -M 2 R E -M A I N A T Z E R O . V O L T M E T E R M l I N D I C A T E S L O W V O L T A G E . C I R C U I T B R E A K E R C B 1 W O N ’ T R E M A I N O N .
POWER SUPPLY OPERATES AT E X C E S S I V E H I G H V O L T A G E . V O L T A G E F L U C T U A T E S D U R I N G O P E R A T I O N . O U T P U T V O L T A G E D O E S N ’ T C H A N G E W H E N D C V O L T A G E A D J U S T C O N T R O L I S R E S E T M A N U A L L Y . V O L T M E T E R M l I N D I C A T E S P O W E R SUPPLY WORKING AT VOLTAGE
B E L O W O P E R A T I N G L I M I T S .
A M M E T E R M 2 S H O W S A B N O R M A L C U R R E N T O R N O C U R R E N T D U R I N G N O R M A L O P E R A T I O N .
POWER SUPPLY HUMS LOUDLY D U R I N G O P E R A T I O N . N u m b e r P a g e 2-5 2 - 5 2 - 6 2-6 2 - 7 2 - 7 2-8 2 - 9 2 - 1 0 2-11 2 - 1 2 2 - 1 3 2 - 1 3
para 2-10 para 2-10
para 2-10 para 2-10
para 2-10 para 2-10
para 2-8 para 2-6 para 2-10 para 2-8 para 2-8 paragraph 2-8 paragraph 2-8 para 2-10
para 2-7 paragraph 2-7 para 2-8 paragraph 2-8 para 2-6 para 2-6 para 2-10 FO-2 FO-3
paragraph 2-7 para 2-8 paragraph 2-8 para 2-6 paragraph 2-8 para 2-7
para 2-7 paragraph 2-7 para 2-8 para 2-8 para 2-6 para 2-8 para 2-6
paragraph 2-8 para 2-6 para 2-7 paragraph 2-7 para 2-8 paragraph 2-8 para 2-8
B E F O R E P E R F O R M I N G T E S T S : SHUT OFF POWER SUPPLY.
D I S C O N N E C T F R O M A C P O W E R S O U R C E . D I S C H A R G E C A P A C I T O R S B Y S H O R T I N G O U T W I T H S H O R T I N G R O D . Diodes T e s t e q u i p m e n t : M u l t i m e t e r T S - 3 5 2 B / U M e a s u r e : I n t e r n a l r e s i s t a n c e , b o t h d i r e c t i o n s . M u l t i m e t e r s e l e c t s w i t c h : R X 1 P r o c e d u r e : R e m o v e p a n e l ( s ) . D i s c o n n e c t d i o d e b e i n g t e s t e d b y r e m o v i n g s c r e w s a n d l e a d s . C o n n e c t m u l t i m e t e r l e a d s t o e n d s o f d i o d e ; t a k e r e a d i n g . R e v e r s e l e a d s o n d i o d e ; t a k e r e a d i n g . D i o d e d e f e c t i v e i f r e a d i n g s h o w s : F o r w a r d r e s i s t a n c e m o r e t h a n 5 0 0 0 o h m s . R e v e r s e r e s i s t a n c e l e s s t h a n 5 0 0 o h m s . O o h m s , b o t h d i r e c t i o n s . R e c o n n e c t d i o d e s . R e p l a c e p a n e l ( s ) . Meter M1
S e t m u l t i m e t e r t o R X 1 0 0 0 . C o n n e c t l e a d s a c r o s s m e t e r t e r m i n a l s ; t a k e r e a d i n g . M u l t i m e t e r s h o u l d r e a d 5 0 , 0 0 0 o h m r e s i s t a n c e a c r o s s t e r m i n a l s . D i f f e r e n t r e a d i n g i n d i c a t e s d e f e c t . A c c u r a c y t e s t : S e t m u l t i m e t e r t o R X 1 . P a r a l l e l - c o n n e c t V o l t m e t e r A N / U S M - 9 8 A a c r o s s m e t e r ’ s t e r m i n a l s . C h e c k z e r o - a d j u s t - m o v e z e r o - a d j u s t s c r e w i n b o t h d i r e c t i o n s . N e e d l e o n M l s c a l e s h o u l d b e m o v e a b l e a b o v e a n d b e l o w z e r o l i n e . Meter M2 F u n c t i o n : 5 0 - m i l l i v o l t m e t e r T e s t e q u i p m e n t : V o l t m e t e r A N / U S M - 9 8 A A c c u r a c y t e s t : P a r a l l e l - c o n n e c t v o l t m e t e r a c r o s s m e t e r t e r m i n a l s . C h e c k z e r o - a d j u s t m o v e m e n t . N e e d l e o n M 2 s c a l e s h o u l d b e m o v e a b l e a b o v e a n d b e l o w z e r o l i n e . Controlled Rectifiers T e s t e q u i p m e n t : M u l t i m e t e r T S - 3 5 2 B / U M e a s u r e : I n t e r n a l r e s i s t a n c e S e t m u l t i m e t e r t o R X 1 . P r o c e d u r e : R e m o v e p a n e l ( s ) . D i s c o n n e c t g a t e a n d c a t h o d e l e a d s o f r e c t i f i e r b e i n g t e s t e d . T e s t s : A n o d e - c a t h o d e r e s i s t a n c e : C o n n e c t m u l t i m e t e r l e a d s t o o p p o s i t e s i d e s o f r e c t i f i e r . R e c t i f i e r d e f e c t i v e i f r e a d i n g s h o w s : O o h m s i n b o t h d i r e c t i o n s . 1 m e g o h m o r h i g h e r i n b o t h d i r e c t i o n s . G a t e - c a t h o d e r e s i s t a n c e : R e v e r s e l e a d s . R e c t i f i e r d e f e c t i v e i f r e a d i n g s h o w s 5 0 0 0 o h m s o r h i g h e r ( I n d i c a t e s o p e n c i r c u i t ) . N O T E
CAPACITORS CARRY A CHARGE AFTER POWER SUPPLY IS SHUT OFF. BEFORE PERFORMING TESTS:
SHUT OFF POWER SUPPLY.
DISCONNECT FROM AC POWER SOURCE.
DISCHARGE CAPACITORS BY SHORTING OUT WITH SHORTING ROD.
General Instructions
T e s t e q u i p m e n t : M u l t i m e t e r T S - 3 5 2 B / U R e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) .
M a k e v i s u a l c h e c k f o r o v e r h e a t e d c o m p o n e n t s o r c i r c u i t s . I f t h e r e i s v i s u a l e v i d e n c e , c h e c k s u s p e c t e d c i r c u i t c a r d c o m p o n e n t w i t h m u l t i m e t e r .
If there is no evidence of overheating, remove PC101 (A1) from power supply (para 2-11). Make r e s i s t a n c e c h e c k s o n f o l l o w i n g p a g e w i t h m u l t i m e t e r .
para 3-6 fig. 2
C o n n e c t i o n : L o c a t i o n o f c o n n e c t o r t e r m i n a l s P C 1 0 1 : ( b o t t o m v i e w )
O p e n f r o n t , r e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) . P u l l i n t e r l o c k s w i t c h u p .
VOLTAGE OUTPUT, POWER TRANSFORMER T1
V o l t a g e m e a s u r e m e n t s , T 1 s e c o n d a r y w i n d i n g s , n o r m a l o p e r a t i n g c o n d i t i o n s :
Between secondary AC voltage indication (approximate)
winding terminals PP-4763 P P - 4 7 6 3 A
T B 4 - 1 T B 4 - 2 5 0 5 2 . 0
T B 1 - 1 1 T B 1 - 1 0 1 1 5 . 0 1 1 5 . 0
T B 1 - 6 T B 1 - 7 3 2 3 3 . 4
T B 1 - 6 T B 1 - 8 6 4 6 6 . 7
DC RESISTANCE, TRANSFORMER and REACTORS
M e a s u r e r e s i s t a n c e w i t h p o w e r O F F . D i s c o n n e c t p o w e r p l u g , t u r n s w i t c h O F F b e f o r e t a k i n g m e a s u r e m e n t s . R e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) . C h e c k t r a n s f o r m e r , r e a c t o r s f o r d e f e c t s b e f o r e m a k i n g r e s i s t a n c e m e a s u r e m e n t s . U s e t r o u b l e s h o o t i n g c h a r t . C A U T I O N N o r m a l r e s i s t a n c e m e a s u r e m e n t s m a y n o t d e t e c t s o m e a r c i n g a n d s h o r t i n g t h a t o c c u r s d u r i n g
R e a c t o r L 1 R e a c t o r L 2 P P - 4 7 6 3 A T1 L1 L 2 C h o k e L 3 T B 2 - 2 T B 4 - 2 T B 1 - 1 2 T B 1 - 1 4 T B 4 - 1 T B 1 - 1 1 T B 1 - 8 T B 2 - 2 T B 4 - 2 C R 2 / C R 3 j u n c t i o n C R 5 h e a t s i n k C R 4 T B 1 - 1 5 T B 1 - 1 6 T B 4 - 2 T B 1 - 1 0 T B 1 - 6 C R 5 h e a t s i n k C R 4 L 3 / R 1 0 j u n c t i o n 0 . 0 1 5 0.001 0 . 1 2 0 . 1 2 0 . 0 1 5 2 . 6 0 . 4 0 . 0 1 5 0.001 1 . 9 N O T E ( * ) F o r a l l r e a d i n g s b e l o w 1 o h m , t a b l e s h o u l d r e a d l e s s t h a n 1 o h m .
T e s t e q u i p m e n t : M u l t i m e t e r T S - 3 5 2 B / U T r a n s f o r m e r T F - 1 7 1 / U S M V o l t m e t e r A N / U R M - 1 4 5 C A U T I O N F o r P P - 4 7 6 3 A , s e t a c i n p u t l i n k s t o 1 1 5 - v o l t o p e r a t i o n b e f o r e c o n n e c t i n g p o w e r s u p p l y a n d t e s t e q u i p m e n t t o s o u r c e .
Voltage Adjust Circuit
S w i t c h C B 1 : O N S e t d c v o l t a g e - a d j u s t c o n t r o l R 4 f u l l y c l o c k w i s e . L o o s e n l o c k n u t o n v a r i a b l e r e s i s t o r R 8 . A d j u s t R 8 u n t i l p o w e r s u p p l y v o l t a g e i s 2 9 v o l t s m i n i m u m , 3 0 v o l t s m a x i m u m , ( t a k e r e a d i n g o n V o l t m e t e r A N / U R M - 1 4 5 ) . T i g h t e n l o c k n u t . C B 1 : O F F C l o s e f r o n t p a n e I . Overvoltage Circuit
Remove rear panel (refer to para 2-10).
C o n n e c t j u m p e r l e a d a c r o s s s i l i c o n C o n t r o l l e d R e c t i f i e r S C R I ( Q 1 ) a s s h o w n . U s e N o . 8 ( o r l a r g e r ) A W G w i r e . S e t t r a n s f o r m e r t o 1 1 5 - v o l t o u t p u t . W i t h n o l o a d c o n n e c t e d a c r o s s p o w e r s u p p l y ’ s d c o u t p u t : I n c r e a s e A C l i n e v o l t a g e i n p u t t o p o w e r s u p p l y u n t i l d c o u t p u t r e a d s 3 5 v o l t s ± 0 . 1 v o l t ( o n V o l t m e t e r M E - 3 0 ( * ) / U ) , o r u n t i l C o n t r o l l e d R e c t i f i e r S C R 2 ( Q 2 ) f i r e s , t r i p p i n g C B 1 .
If SCR2(Q2) does not fire:
T u r n V a r i a b l e R e s i s t o r P C 1 0 1 R 1 2 3 ( A 1 R 2 3 ) c l o c k w i s e u n t i l S C R 2 ( Q 2 ) f i r e s a t 3 5 v o l t s ± 0 . 1 v o l t . Refer to figure 1, figure 2, Chapter 3-6.
S e a l a d j u s t m e n t s c r e w o n P C 1 0 1 R 1 2 3 ( A 1 R 2 3 ) . R e m o v e a l l i n p u t p o w e r t o s u p p l y .
S h o r t o u t c a p a c i t o r s w i t h s h o r t i n g r o d . B e c a r e f u l d u r i n g r e m o v a l a n d r e p l a c e m e n t . Y o u c a n p r e v e n t a c c i d e n t a l d a m a g e t o o t h e r p a r t s , a n d y o u c a n p r e v e n t p o t e n t i a l s h o r t c i r c u i t s c a u s e d b y d r o p p e d h a r d w a r e . W h e n r e m o v i n g a n d r e p l a c i n g a p a r t , c h e c k c a r e f u l l y f o r l o o s e h a r d w a r e o r i n s e c u r e e l e c t r i c a l c o n n e c t i o n s . D o n o t o p e r a t e e q u i p m e n t u n t i l y o u m a k e t h e s e c h e c k s . N O T E N o s p e c i a l t o o l s o r p r o c e d u r e s a r e n e e d e d t o r e m o v e a n d r e p l a c e p o w e r s u p p l y p a r t s .
2-10. REMOVING AND REPLACING PANELS.
T h e p o w e r s u p p l y ’ s f r o n t , t o p , a n d r e a r p a n e l s c a n b e r e m o v e d t o a l l o w m a i n t e n a n c e i n s i d e t h e u n i t .
T o r e p l a c e f r o n t p a n e l , r e p l a c e s c r e w s , w a s h e r s , n u t s .
Rear Panel
N O T E
T w o p e o p l e a r e r e q u i r e d f o r r e m o v a l a n d r e p l a c e m e n t .
P o s i t i o n p o w e r s u p p l y t o p r o v i d e a c c e s s t o t h e b o t t o m .
Remove four screws, washers, nuts on the bottom (rear side) of the power supply. R e t u r n p o w e r s u p p l y t o u p r i g h t p o s i t i o n .
T a g a n d r e m o v e t h e f o l l o w i n g w i r e s f r o m t h e r e a r p a n e l :
P P - 4 7 6 3
W6 from SCR1.
W6 from Q1 (heats ink). W8 and W134 from TB3. W12 and W13 from TB2. W201 and W202 from FL1. POS and NEG from FL1. R e m o v e r e a r p a n e l .
T o r e p l a c e r e a r p a n e l , s o l d e r i d e n t i f i e d w i r e s t o p r o p e r t e r m i n a l s . Position rear panel.
Replace six screws, washers, nuts on the side panels.
para 2-10
Carefully remove top panel (para 2-10). Loosen hexagon nuts on links.
M o v e t o c o r r e c t t e r m i n a l l u g s . Tighten nuts.
R e p l a c e p a n e l s .
P P - 4 7 6 3 A O N L Y
R E M O V E L o o s e n t w o m a c h i n e s c r e w s ( f o u r s c r e w s , P P - 4 7 6 3 A ) . O p e n f r o n t p a n e l . R e m o v e s c r e w s , w a s h e r s , n u t s . R e m o v e s w i t c h c o v e r b r a c k e t . R e m o v e s w i t c h c o v e r . D i s c o n n e c t l e a d s f r o m c i r c u i t b r e a k e r a n d t a g . R e m o v e c i r c u i t b r e a k e r .
O p e n f r o n t p a n e l . R e m o v e t h r e e m a c h i n e s c r e w s , w a s h e r s , n u t s . R e m o v e m e t e r m o u n t i n g g a s k e t . L o o s e n t e r m i n a l l u g s , d i s c o n n e c t l e a d s ( 4 7 6 3 ) , u n s o l d e r c o n n e c t i o n s , a n d t a g . R e m o v e m e t e r .
REMOVE
Open front panel.
Remove three machine screws, washers, nuts.
Remove meter mounting gasket.
Loosen terminal lugs, disconnect leads and tag.
Remove meter.
REPLACE
Install new meter.
Replace leads, tighten terminal lugs.
Replace meter mounting gasket.
REMOVE
Open front panel.
Remove two outside screws, nuts, washers.
Unsolder leads, and tag.
Remove locknut, mounting nut, washer.
Remove resistor.
REPLACE
RESISTOR R8
Put new resistor in place.
Replace screw, nut, washer.
Solder leads.
Replace two outside screws, nuts, washers.
REMOVE
Open front panel.
Remove two outside screws, nuts, washers.
Unsolder leads and tag.
REMOVE
O p e n f r o n t p a n e l .
R e m o v e t w o o u t s i d e s c r e w s , n u t s , w a s h e r s . Unsolder resistor lead.
R e m o v e n u t , w a s h e r , w i r e w r a p , n u t , w a s h e r s f r o m t e r m i n a l . C u t w i r e w r a p a r o u n d r e s i s t o r . R e m o v e r e s i s t o r . REPLACE P u t r e s i s t o r i n p l a c e . I n s t a l l n e w w i r e w r a p a r o u n d r e s i s t o r . R e p l a c e n u t , w a s h e r , w i r e w r a p , n u t , w a s h e r . S o l d e r r e s i s t o r l e a d . C A P A C I T O R S C 3 ( P P - 4 7 6 3 ) R E M O V E O p e n f r o n t p a n e l . R e m o v e r e s i s t o r R 1 1 ( f o l l o w s t e p s a b o v e ) . Unsolder leads. R e m o v e c a p a c i t o r . REPLACE P u t n e w c a p a c i t o r i n p l a c e . S o l d e r l e a d s . R e p l a c e r e s i s t o r R 1 1 ( f o l l o w s t e p s a b o v e ) .
Open front panel.
Remove and tag leads from right heatsink: W16 from CR3;
W15 from CR2 Remove right heatsink:
Remove nuts, washers, spacers, and choke lead from 7/16” bolt at top of heatsink. Remove two nuts, washers, spacers at bottom of heatsink.
Remove mounting nut on diode.
Use care in removing diodes. Observe polarity when removing and replacing diodes.
Remove top panel (para 2-10) Open front panel.
Remove and tag leads from right heatsink: W16 from CR3;
W15 from CR2 Remove right heatsink:
Remove nuts, washers, spacers, and choke lead from 7/16” bolt at top of heatsink. Remove two nuts, washers, spacers at bottom of heatsink.
Remove mounting nut on diode.
Use care in removing diodes. Observe polarity when removing and replacing diodes.
Remove diode. REPLACE I n s t a l l n e w d i o d e . T i g h t e n m o u n t i n g n u t t o 2 0 i n c h - p o u n d s t o r q u e w i t h t o r q u e w r e n c h . R e p l a c e h e a t s i n k : R e p l a c e t w o m a c h i n e s c r e w s a t b o t t o m . R e p l a c e n u t s , w a s h e r s , s p a c e r s , a n d c h o k e l e a d o n 7 / 1 6 ” b o l t a t t o p o f h e a t s i n k . C o n n e c t l e a d s : W 1 6 t o C R 3 ;
R E M O V E R e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) . O p e n f r o n t p a n e l . D i s c o n n e c t l e a d s W 1 7 , W 1 8 . R e m o v e m o u n t i n g s c r e w , w a s h e r s o n f r o n t , n u t o n r e a r . R e m o v e b r a c k e t r e t a i n i n g s c r e w , n u t , n u t s a n d w a s h e r s . S l i d e r e a c t o r s t r a i g h t o u t .
C a p a c i t o r s c a r r y a c h a r g e a f t e r p o w e r s u p p l y i s s h u t o f f . S h o r t o u t c a p a c i t o r s w i t h s h o r t i n g r o d .
R E M O V E
Remove top panel.
Remove left side panel. Remove six machine screws, three hex nuts.
Remove four screws on side panel. Remove two screws from capacitor bank a s s e m b l y s i d e p a n e l .
Remove two screws from + and - bus b a r s o f d e f e c t i v e c a p a c i t o r .
M a k e s u r e p o s i t i v e m a r k i n g ( + ) o n c a p a c i t o r g o e s t o t h e p o s i t i v e m a r k i n g ( + ) o n b u s b a r .
Remove top panel (para 2-10). R e m o v e n u t s , w a s h e r s . T a g a n d d i s c o n n e c t l e a d s . R e m o v e r e s i s t o r . REPLACE I n s t a l l n e w r e s i s t o r . C o n n e c t l e a d s . R e p l a c e n u t s , w a s h e r s . R e p l a c e t o p p a n e l . R E M O V E R e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) . U n b o l t r e a r p a n e l . D i s c o n n e c t l e a d s a n d t a g : W 6 f r o m d i o d e h e a t s i n k W 8 f r o m T B 3 - 2 W134 from TB3-1 P O S w i r e f r o m T B 1 P O S t e r m i n a l N E G w i r e f r o m T B 1 N E G t e r m i n a l L1, L2 from TB1 terminal L2 (PP-4763) L l , L 2 f r o m T B 1 t e r m i n a l L 2 ( P P - 4 7 6 3 A ) D C o u t p u t t e r m i n a l l e a d s W 1 3 6 f r o m T B 2 - 4 . R e m o v e m o u n t i n g n u t , w a s h e r . R e m o v e d i o d e . REPLACE
Apply thermal compound (Item No. 3 Appendix B) to mounting surface of heatsink.
I n s t a l l n e w S C R .
Torque to 120 inch/pounds with t o r q u e w r e n c h .
Remove W13 from TB1-18.
Remove TB2 by removing two mounting screws. Remove cathode lead of SCR from TB2-1.
Remove gate lead of SCR from TB2-3.
R e m o v e S C R m o u n t i n g n u t , w a s h e r , a n d I o c k w a s h e r .
REPLACE
Apply thermal compound (Item No. 3
Appendix B) to mounting surface of heatsinks. I n s t a l l n e w S C R w i t h w a s h e r , I o c k w a s h e r , n u t .
R E M O V E R e m o v e t o p p a n e l ( p a r a 2 - 1 0 ) . R e m o v e r e a r p a n e l . R e m o v e c a b l e c o n n e c t o r : R e m o v e m a c h i n e s c r e w s . R e m o v e c o n n e c t o r c l a m p s . R e m o v e n u t s , w a s h e r s . D i s c o n n e c t t h r e e c a b l e c o n n e c t i o n s . R e m o v e c a b l e . R E M O V E REPLACE I n s t a l l n e w c a b l e . R e p l a c e c a b l e c o n n e c t i o n s . R e p l a c e n u t s , w a s h e r s . R e p l a c e c a b l e c o n n e c t o r c l a m p s . R e p l a c e m a c h i n e s c r e w s . R e p l a c e r e a r p a n e l . R e p l a c e t o p p a n e l . R E P L A C E R e m o v e s c r e w s . R e m o v e c a b l e p l u g c l a m p . R e m o v e c o v e r i n s u l a t o r . D i s c o n n e c t l e a d s i n s i d e . R e m o v e c a b l e p l u g . I n s t a l l n e w c a b l e p l u g . C o n n e c t l e a d s i n s i d e p l u g . R e p l a c e c o v e r i n s u l a t o r . R e p l a c e c a b l e p l u g c l a m p . R e p l a c e s c r e w s . N O T E M a k e s u r e c o n n e c t i o n s a r e c o r r e c t .
p l a t e : r e m o v e f o u r s c r e w s , n u t s w a s h e r s .
REPLACE
I n s t a l l n e w f a n m o t o r a s s e m b l y o n t o c h a s s i s p l a t e : r e p l a c e f o u r m a c h i n e s c r e w s , n u t s , w a s h e r s .
TRANSFORMER T1
R E M O V E
Remove top panel, rear panel; open front panel (para 2-10). Disconnect leads W70 and W71 from terminals TB4-1 and TB4-2.
P P 4 7 6 3 A
R e m o v e n u t s , w a s h e r s , s t u d s , a n d s t a n d o f f s t h a t s e c u r e T B 1 t o t r a n s f o r m e r . Remove wires from TB1 at 12, 13, 14, 15, 16, 6, 7, 8, 10, 11, and tag.
U s e r a t c h e t , 7 / 1 6 ” s o c k e t a n d e x t e n s i o n t o r e m o v e f o u r n u t s f r o m t r a n s f o r m e r f r a m e a s s e m b l y . L i f t t r a n s f o r m e r o v e r r e a r m o u n t i n g b r a c k e t a n d c a r e f u l l y r e m o v e . R E P L A C E PP 4763 C a r e f u l l y i n s t a l l n e w t r a n s f o r m e r R e p l a c e f o u r n u t s o n t r a n s f o r m e r f r a m e a s s e m b l y . R e p l a c e a l l l e a d s . R e a t t a c h T B 1 t o t r a n s f o r m e r : R e p l a c e n u t s , w a s h e r s , s t u d s , s t a n d o f f s . P P 4 7 6 3 A C a r e f u l l y i n s t a l l n e w t r a n s f o r m e r . R e p l a c e f o u r n u t s o n t r a n s f o r m e r f r a m e a s s e m b l y .
Replace leads on TB1 at 12, 13, 14, 15, 16, 6, 7, 8, 10, 11, and tag. R e a t t a c h T B 1 t o t r a n s f o r m e r :
R e p l a c e n u t s , w a s h e r s , s t u d s , s t a n d o f f s .
para 2-10 N O T E I n s t a l l d i o d e o n r e a r o f t e r m i n a l b o a r d o n l y . 1 8 . I N T E R L O C K S W I T C H R E M O V E R E P L A C E
Install new diode.
R e p l a c e d i o d e m o u n t i n g n u t . Solder and tag:
W54 to TB 4-1 W53 to TB 4-2
R E P L A C E
2-13 R e a d i n s t r u c t i o n s c a r e f u l l y b e f o r e u s i n g c h a r t . P e r f o r m e a c h s t e p i n s e q u e n c e . D O N O T v a r y s e q u e n c e . P e r f o r m a l l r e q u i r e d a c t i o n s . P e r f o r m e a c h t e s t p r o c e d u r e . C h e c k e a c h p r o c e d u r e a g a i n s t i t s p e r f o r m a n c e s t a n d a r d . T o o l s , t e s t e q u i p m e n t , a n d m a t e r i a l s : r e f e r t o p a g e 2 - 1 . General
Disconnect power supply from power source ond other equipment. T e s t e q u i p m e n t a n d m a t e r i a l s : N o n e r e q u i r e d . T e s t c o n n e c t i o n s a n d c o n d i t i o n s : N o c o n n e c t i o n s n e c e s s a r y . Procedures C o n t r o l s e t t i n g s : A C p o w e r s w i t c h m a y b e i n a n y p o s i t i o n . L e g e n d : T e s t P r o c e d u r e s P e r f o r m a n c e S t a n d a r d Test Chart ( 1 ) C h e c k c a s e f o r d a m a g e , m i s s i n g p a r t s , c o n d i t i o n o f p a i n t : N o d a m a g e t o c a s e , n o p a r t s m i s s i n g . S u r f a c e s n e e d i n g p a i n t d o n o t s h o w b a r e m e t a l . P a n e l l e t t e r i n g r e a d a b l e .
P l u g s e c u r e l y a t t a c h e d t o c a b l e , n o t d a m a g e d . ( 7 ) R e s i s t a n c e c h e c k o f i n t e r l o c k s w i t c h S 1 :
O p e r a t e s p r o p e r l y ( r e f e r t o S1 open reading is O ohms. S 1 c l o s e d r e a d i n g i s 2 . 2 K . R e p l a c e t o p p a n e l .
2-14. STATIC VOLTAGE REGULATION TEST
Test Equipment and Materials
T r a n s f o r m e r T F - 1 7 1 / U S M V o l t m e t e r A N / U S M - 9 8 A V o l t m e t e r M E - 3 0 ( * ) / U T e s t s w i t c h ( s i n g l e - p o l e , 6 0 a m p e r e ) R e s i s t o r , 0 . 5 6 o h m , 1 0 0 0 w a t t s R e s i s t o r , 1 . 3 o h m s , 1 0 0 0 w a t t s
Test Connections and Conditions
C o n n e c t t e s t e q u i p m e n t a s s h o w n .
C A U T I O N
F o r P P - 4 7 6 3 A , s e t a c i n p u t l i n k s t o 1 1 5 - v o l t o p e r a t i o n b e f o r e c o n n e c t i n g power supply and test equipment to source (para 2-10).
T E S T E Q U I P M E N T S E T T I N G S : T r a n s f o r m e r
M u l t i m e t e r
C o n t r o l : 1 1 5 v o l t s
F U N C T I O N s w i t c h : A C V O L T S , 2 5 0 V O L T S C A L E Black test lead: OHMS – DC + AC jack
Red test lead: 2.5 jack, 1000 OHMS PER VOLT A C D C c o l u m n V o l t m e t e r A N / U S M - 9 8 A Range: 50 volt N u l l : V T V M V o l t m e t e r M E - 3 0 ( * ) / U S w i t c h : 0 . 3 v o l t s ( c a l i b r a t e d ) L o a d 0 . 5 6 o h m , 1 0 0 0 - w a t t r e s i s t o r T e s t s w i t c h O p e n N O T E K e e p t e s t e q u i p m e n t a t t h e s e s e t t i n g s e x c e p t w h e r e n o t e d . ( 1 ) E q u i p m e n t s e t a s n o t e d a b o v e . 1 C h e c k a c c u r a c y o f v o l t m e t e r M l ; c o m p a r e A N / U S M - 9 8 A r e a d i n g s . 2 C l o s e t e s t s w i t c h . C h e c k r i p p l e v o l t a g e o n M E - 3 0 ( * ) / U . 3 C h e c k d c o u t p u t v o l t a g e o n A N / U S M - 9 8 A . ( 2 ) T r a n s f o r m e r : 1 2 7 v o l t s . C i r c u i t b r e a k e r C B 1 O N . S e t d c v o l t a g e a d j u s t R 4 f o r 2 8 - v o l t o u t p u t . L e s s t h a n 1 . 0 v o l t d i f f e r e n c e b e t w e e n r e a d i n g s . V o l t a g e w i t h i n 1 % r m s ( a p p r o x i m a t e l y 3 % p e a k t o p e a k ) o f o u t p u t v o l t a g e . R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( m a x i m u m v o l t a g e d e v i a t i o n 2 8 0 m i l l i v o l t s o r l e s s ) . DC voltage: 28 volts. R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( 2 8 0 m V o r
( 4 ) T r a n s f o r m e r : 1 0 3 v o l t s . L o a d : 1 . 3 - o h m r e s i s t o r . T e s t s w i t c h c l o s e d . C h e c k d c o u t p u t v o l t a g e . ( 5 ) T r a n s f o r m e r : 1 2 7 v o l t s . L o a d : 1 . 3 - o h m r e s i s t o r . T e s t s w i t c h c l o s e d . C h e c k d c o u t p u t v o l t a g e . ( 6 ) T e s t s w i t c h o p e n . L o a d r e d u c e d t o z e r o . C h e c k d c o u t p u t v o l t a g e . ( 7 ) T r a n s f o r m e r : 1 0 3 v o l t s . T e s t s w i t c h o p e n . L o a d r e d u c e d t o z e r o . C h e c k d c o u t p u t v o l t a g e . ( 8 ) T r a n s f o r m e r : 1 2 7 v o l t s . T e s t s w i t c h o p e n . L o a d r e d u c e d t o z e r o . C h e c k d c o u t p u t v o l t a g e . ( 9 ) L o a d : 1 . 3 - o h m r e s i s t o r . T e s t s w i t c h c l o s e d . C h e c k d c o u t p u t v o l t a g e . ( 1 0 ) L o a d : 1 . 3 - o h m r e s i s t o r . T e s t s w i t c h c l o s e d . C h e c k d c o u t p u t v o l t a g e . D C v o l t a g e : 2 8 v o l t s R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( 2 8 0 m V o r l e s s d e v i a t i o n ) . D C v o l t a g e : 2 8 v o l t s R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( 2 8 0 m V o r l e s s d e v i a t i o n ) . D C v o l t a g e : 2 8 v o l t s R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( 2 8 0 m V o r l e s s d e v i a t i o n ) . D C v o l t a g e : 2 8 v o l t s R e a d i n g w i t h i n + 0 . 5 % o f 2 8 v o l t s d c ( 2 8 0 m V o r l e s s d e v i a t i o n ) . D C v o l t a g e : 2 8 v o l t s R e a d i n g w i t h i n + 0 . 5 ’ % o f 2 8 v o l t s d c ( 2 8 0 m V o r l e s s d e v i a t i o n ) . D C v o l t a g e : S e t f o r m i n i m u m v o l t a g e (full Cw). R e a d i n g b e t w e e n 2 2 a n d 2 7 v o l t s d c . D C v o l t a g e : S e t f o r m a x i m u m v o l t a g e ( f u l l C W) . R e a d i n g b e t w e e n 2 9 a n d 3 0 v o l t s d c . R E S E T D C V O L T A G E A D J U S T F O R 2 8 - V O L T O U T P U T ± 0 . 1 V O L T C I R C U I T B R E A K E R : O F F
Hz power source is available, test PP-4763A at 230-volt input. P r o c e d u r e :
Set TB-1 ac input links to 230 volts ac. C o n n e c t p o w e r c a b l e t o 2 3 0 - v o l t s o u r c e .
Repeat test equipment settings, control settings for step 1 of paragraph 2-14 in test chart. Repeat ripple voltage, dc output voltage checks in step 1 of paragraph 2-14.
2 - 1 5 . T E S T D A T A S U M M A R Y S u m m a r y o f p e r f o r m a n c e s t a n d a r d s . Input V o l t a g e 1 1 5 v o l t s 115 or 230 volts F r e q u e n c y 50/60 Hz P h a s e S i n g l e C u r r e n t ( f u l l l o a d ) 2 3 a m p e r e s 2 3 a m p e r e s a t 1 1 5 - v o l t i n p u t 1 1 . 5 a m p e r e s a t 2 3 0 - v o l t i n p u t O u t p u t
V o l t a g e 28-volt operation (27-29 volts dc) C u r r e n t ( f u l l l o a d ) 5 0 a m p e r e s R i p p l e V o l t a g e 1 . 0 p e r c e n t r m s P P - 4 7 6 3 P P - 4 7 6 3 A P P - 4 7 6 3 P P - 4 7 6 3 A
CHAPTER 3
G E N E R A L S U P P O R T M A I N T E N A N C E
S e c t i o n I . G E N E R A L I N F O R M A T I O N
P A G E General . . . 3-2 Repair Parts, Tools, Test Equipment, and Materials . . . 3-2
S e c t i o n I I . T R O U B L E S H O O T I N G
Procedures . . . 3-3 Testing and Troubleshooting Circuit Card Assembly PC101(A1) . . . 3-3
Section III. MAINTENANCE PROCEDURES
Removing and Replacing Circuit Card Assembly PC101(A1) . . . 3-6 Repairing Circuit Card Assembly PC101(A1) . . . .
Section IV. TEST PROCEDURES
. . . 3 - 6
Dynamic Voltage Regulation Test . . . 3-10 Procedures . . . 3-10 Test DataSummary . . . 3-13
L o w v o l t a g e , h i g h a m p e r a g e c u r r e n t i s p r e s e n t a t o u t p u t c o n n e c t i o n s a n d c o n n e c t i o n s i n s i d e e q u i p m e n t . S h u t o f f p o w e r s u p p l y b e f o r e p e r f o r m i n g m a i n t e n a n c e . B e c a r e f u l w h e n w o r k i n g w i t h 1 1 5 o r 2 3 0 - v o l t a c l i n e c o n n e c t i o n s . S e r i o u s i n j u r y o r d e a t h m a y r e s u l t f r o m c o n t a c t w i t h t e r m i n a l s . T h i s c h a p t e r c o v e r s g e n e r a l s u p p o r t t r o u b l e s h o o t i n g , m a i n t e n a n c e , a n d t e s t i n g p r o c e d u r e s f o r t h e p o w e r s u p p l y . S e c t i o n I l i s t s t h e t o o l s , t e s t e q u i p m e n t , a n d m a t e r i a l s n e e d e d t o p e r f o r m g e n e r a l s u p p o r t m a i n t e n a n c e . T r o u b l e s h o o t i n g p r o c e d u r e s a r e d e s c r i b e d i n S e c t i o n I I , m a i n t e n a n c e p r o c e d u r e s i n S e c t i o n I I I , a n d t e s t p r o c e d u r e s i n S e c t i o n I V . N O T E T h i s c h a p t e r i s c o n f i n e d t o m a i n t e n a n c e o f c i r c u i t c a r d a s s e m b l y P C 1 0 1 ( A 1 ) . F o r a l l o t h e r m a i n t e n a n c e i n s t r u c t i o n s , s e e C h a p t e r 2 .
3-2. REPAIR PARTS, TOOLS, TEST EQUIPMENT, AND MATERIALS
Repair Parts: Refer to TM 11-5820-765-34P-1. S p e c i a l T o o l s : N o s p e c i a l t o o l s a r e n e e d e d . T o o l s , T e s t E q u i p m e n t , a n d M a t e r i a l s : Item N a t i o n a l S t o c k N u m b e r T O O L S T o o l K i t , E l e c t r o n i c E q u i p m e n t T K - 1 0 0 / G T o o l K i t , E l e c t r o n i c E q u i p m e n t T K - 1 0 5 / G 5 1 8 0 - 0 0 - 6 0 5 - 0 0 7 9 5 1 8 0 - 0 0 - 6 1 0 - 8 1 7 7
R e s i s t o r , 1 . 3 o h m s , 1 0 0 0 w a t t s T e s t S w i t c h , S i n g l e - P o l e , 6 0 a m p e r e W i r e , E l e c t r i c a l , S t r a n d e d ; N o . 8 A W G
Section II. TROUBLESHOOTING
5 9 0 5 - 0 0 - 0 6 4 - 4 6 7 9
3 - 3 . P R O C E D U R E S
F o l l o w p r o c e d u r e s i n C h a p t e r 2 t o l o c a l i z e a n d i s o l a t e t r o u b l e . U s e p a r a g r a p h 3 - 4 t o t e s t a n d t r o u b l e s h o o t t h e c i r c u i t c a r d a s s e m b l y .
3-4. TESTING AND TROUBLESHOOTING CIRCUIT CARD ASSEMBLY PC101(A1).
C a p a c i t o r s c a r r y a c h a r g e a f t e r p o w e r s u p p l y i s s h u t o f f . B e f o r e p e r f o r m i n g t e s t s : S h u t o f f p o w e r s u p p l y . D i s c o n n e c t f r o m a c p o w e r s o u r c e . D i s c h a r g e c a p a c i t o r s b y s h o r t i n g o u t w i t h s h o r t i n g r o d . General Instructions
Remove top panel (para 3-5).
M a k e v i s u a l c h e c k f o r o v e r h e a t e d c o m p o n e n t s o r c i r c u i t s . I f t h e r e i s v i s u a l e v i d e n c e , c h e c k s u s p e c t e d c i r c u i t c a r d c o m p o n e n t w i t h m u l t i m e t e r .
If there is no evidence of overheating, remove circuit card from the unit (para 3-5) and ex-a m i n e i t . I f t h e b o ex-a r d i s b l i s t e r e d , c r ex-a c k e d , o r b r o k e n , t h e b o ex-a r d m u s t b e r e p l ex-a c e d . Y o u c ex-a n r e p l a c e d e f e c t i v e c o m p o n e n t s a n d r e p a i r c r a c k e d o r o p e n - c i r c u i t e d w i r i n g .
Resistance Measurements
P C 1 0 1 J 1 0 1 B e t w e e n t e r m i n a l s F o r w a r d r e s i s t a n c e R e v e r s e r e s i s t a n c e . 1 2 - 3 0 1 0 K H i g h e r ( g r e a t e r t h a n 2 0 K ) 1 2 - 2 6 1 0 K H i g h e r ( g r e a t e r t h a n 2 0 K ) 4 - 6 1 K - 4 K 1 K - 4 K 12-34 1 1 K I n f i n i t y 2 6 - 3 0 4 5 K 4 5 K 6 - 1 2 Z e r o Z e r o 6 - 3 6 H i g h ( g r e a t e r t h a n 1 0 K ) H i g h ( g r e a t e r t h a n 1 0 K ) 6 - 3 8 H i g h ( g r e a t e r t h a n 1 0 K ) H i g h ( g r e a t e r t h a n 1 0 K ) 10-22 H i g h ( g r e a t e r t h a n 1 0 K ) H i g h ( g r e a t e r t h a n 1 0 K ) 10-12 1 4 K 2 0 0 K C h e c k i n g A 1 ( P P - 4 7 6 3 - A ) M e a s u r e : R e s i s t a n c e o f a s s e m b l y c o m p o n e n t s . T e s t p o i n t s : A 1 T P 1 t h r o u g h A 1 T P 6 . C o n n e c t i o n s : L o c a t i o n o f t e s t p o i n t s :
V o l t m e t e r , E l e c t r o n i c M E - 3 0 ( * ) / U M e a s u r e : C h a r a c t e r i s t i c v o l t a g e s , w a v e s h a p e s .
N O T E
Use extender board; if none available, modify a test lead for voltage or wave s h a p e .
A1 TEST POINTS BETWEEN VOLTAGE OR WAVE SHAPE
T B 1 - 8 A 1 T P 5 20 volts dc
A 1 T P 2 T B 1 - 8 2 0 v o l t s d c
A 1 T P 6 T B 1 - 8 9 volts dc
T B 2 - 4 A 1 T P 6 9 volts dc
R e m o v e r e t a i n i n g b r a c k e t n u t s , w a s h e r s . R e m o v e r e t a i n i n g b r a c k e t s . L i f t c i r c u i t c a r d a s s e m b l y s t r a i g h t u p f r o m s o c k e t . C A U T I O N B e c a r e f u l n o t t o b r e a k s o l d e r c o n n e c t i o n s w h e n p u l l i n g t h e c i r c u i t c a r d . REPLACE I n s e r t c i r c u i t c a r d i n t o s o c k e t . B e s u r e t h a t t h e c i r c u i t c a r d t e r m i n a l p o i n t s a r e s e t a l l t h e w a y i n t o t h e s o c k e t . R e p l a c e r e t a i n i n g b r a c k e t s , n u t s , w a s h e r s .
3 - 6 . REPAIRING CIRCUIT CARD ASSEMBLY PC101(A1) (figs. 1 and 2)
Removing Protective Coating
Adequate ventilation should be provided while using TRICHLOROTRIFLUOROETHANE. Pro-longed breathing of vapor should be avoided. The solvent should not be used near heat or open flame; the products of decomposition are toxic and irritating. Since TRICHLOROTRI-FLUOROETHANE dissolves natural oils, prolonged contact with skin should be avoided. When necessary, use gloves which the solvent cannot penetrate. If the solvent is taken internally, consult a physician immediately.
Use only a pencil-type soldering iron with a maximum rating of 25 watts.
Excessive heat will cause printed wiring conductors to separate from the
board. For additional soldering techniques, refer to TB SIG 222.
Repair printed circuit wiring that has a crack, pinhole, cut, or notch more than 30 percent of the
wire’s width.
Procedure:
Remove protective coating.
Place a short length of flat bus wire over the defective wiring and hold it firmly in place.
Solder the entire length of bus wire to the wiring.
Do not apply heat longer than needed. Prolonged heat can separate the
con-ductor from the card; this damage cannot be repaired.
Apply protective coating to exposed area after completing repairs.
Replacing Defective Parts
Remove defective part:
Cut leads on part between part and circuit card mounting holes.
Cut leads as close to mounting holes as possible.
Remove protective coating around the part on the card’s printed wiring side.
Heat printed wiring at mounting holes with soldering iron until solder melts.
Remove excess solder and remaining pieces of wire leads.
Do not apply heat longer than needed. Prolonged heat can separate the
printed wiring from the card, which will damage the care.
Bend the leads of replacement part to fit mounting holes.
Insert leads in mounting holes from parts side of card; press part firmly against card.
On card’s wiring side, cut leads of part; leave approximately 1/8 inch of leads protruding
from card.
P r o t e c t i v e c o a t i n g E C 1 1 0 3 i s t o x i c . T h e w o r k a r e a m u s t b e w e l l v e n t i l a t e d . A v o i d b r e a t h i n g t h e f u m e s .
I f t h e c o a t i n g c o m e s i n c o n t a c t w i t h s k i n , i m m e d i a t e l y w a s h t h e s k i n w i t h s o a p a n d w a t e r .
Use a rubber eraser to clean areas to be coated. P r e p a r e t h e p r o t e c t i v e c o a t i n g m i x t u r e :
Mix 70 parts protective coating (Item No. 2, Appendix B) with 30 parts naphtha (parts by volume) (Item No. 4, Appendix B). Stir mixture thoroughly.
A p p l y c o a t i n g m i x t u r e t o c a r d b y s p r a y i n g , d i p p i n g , o r b r u s h i n g . W h e n b r u s h i n g , b e c a r e f u l t o p r e v e n t b u b b l e s f r o m f o r m i n g . Set coated card aside; allow it to dry in fresh air for five hours.
Section IV. TEST PROCEDURES
3 - 7 . P R O C E D U R E S
A f t e r p e r f o r m i n g m a i n t e n a n c e o n c i r c u i t c a r d a s s e m b l y , p e r f o r m s t a t i c v o l t a g e r e g u l a t i o n t e s t ( p a r a 2 1 4 ) a n d d y n a m i c v o l t a g e r e g u l a t i o n t e s t b e l o w . R e p a i r e d e q u i p m e n t m u s t m e e t p e r
-f o r m a n c e s t a n d a r d s g i v e n o n p a g e 3 - 1 1 .
C A U T I O N
F o r P P - 4 7 6 3 A , s e t a c i n p u t l i n k s t o 1 1 5 v o l t o p e r a t i o n b e f o r e c o n n e c t i n g p o w e r s u p p l y a n d t e s t e q u i p m e n t t o s o u r c e .
T E S T L E G E N D
TEST EQUiPMENT EQUIPMENT UNDER TEST
TEST PROCEDURE PERFORMANCE STANDARD
T E S T E Q U I P M E N T S E T T I N G S : T r a n s f o r m e r M u l t i m e t e r V o l t m e t e r A N / U S M - 9 8 A C o n t r o l : 1 1 5 v o l t s F U N C T I O N s w i t c h : A C V O L T S , 2 5 0 V O L T S C A L E B l a c k t e s t l e a d : O H M S - D C ± A C j a c k
Red test lead: 2.5 jack, 1000 OHMS PER VOLT A C - D C c o l u m n
R a n g e : 5 0 v o l t N u l l : V T V M
K e e p t e s t e q u i p m e n t a t t h e s e s e t t i n g s e x c e p t w h e r e n o t e d . 1 . E q u i p m e n t s e t a s n o t e d a b o v e . P o w e r O N . D C v o l t a g e a d j u s t R 4 ; 2 8 - v o l t o u t p u t . 2 . C l o s e t e s t s w i t c h . T r a n s i e n t v o l t a g e l e s s t h a n 5 v o l t s . C h e c k d y n a m i c r e s p o n s e o n o s c i l l o s c o p e . R e s p o n s e t i m e s :
PP-4763: Recovery
