repair lcd

(1)

1

1 7-Step Method for

7-Step Method for

Electronic Troubleshooting

Ken Reed

System Improvements, Inc.

238 South Peters Road, Suite 301

Knoxville, Tennessee 37923 USA

Phone: 865-539-2139 Fax: 865-539-4335

web: www.taproot.com

Scenario #1

•

• You are enjoying a leisurely day by the pool.

You are enjoying a leisurely day by the pool.

Man, it’s hot out here!

•

• Your wife

Your wife calls from

calls from the kitchen

the kitchen door.

door. “The

“The

thermostat

thermostat for the

for the air conditione

air conditioner is br

r is broke.

oke. It’s

It’s

getting hot in here!”

•

(2)

Scenario #2

•

• You are the maintenance supervisor at a coal

You are the maintenance supervisor at a coal

mine.

mine. You must m

You must move 600 ton

ove 600 tons / hr ou

s / hr out of the

t of the

mine.

•

• You get

You get a call fr

a call from the

om the control ro

control room.

om. “The

“The

conveyor be

conveyor belt is dow

lt is down again.

n again. It just

It just shut off.”

shut off.”

•

• You have about 1 hour before the hopper is

You have about 1 hour before the hopper is

empty and the rail cars are no longer being

filled.

•

• Consequences: $400,000 / hr.

Consequences: $400,000 / hr.

Scenario #3

•

• You are the Reactor Control Chief on a

You are the Reactor Control Chief on a

nuclear su

nuclear submarine.

bmarine. You awa

You awaken whe

ken when you

n you

hear all the ventilation fans turn off, and a

loudspeaker announcement, “Reactor

Scram.”

•

• The ship is

The ship is currently operating under the

currently operating under the

north polar ice, with no place to surface within

6 hours.

•

• You have 3

You have 3

!

_{hours left on battery power.}

•

(3)

Which is worse??

Fix it

NOW!!!

Ken Reed

Senior Associate

System Improvements

(4)

Who am I?

• 21 years Nuclear Submarine Experience

– Retired Master Chief Electronics Technician

– Served on:

• Ballistic Missile Boat

• Fast Attacks

• Nuclear Research sub

– Last boat – USS SEAWOLF

Electronic Troubleshooting

• Topics:

– Electronic vs Other Equipment

– Before you start…

– Troubleshooting Methods

– Organizing the Team

– Seven Step Process

(5)

Note About This Presentation

• I am going by my experience, which often dictates

a worst-case “must fix” scenario

• If your needs are not this critical, take what you

need from what you see today

Troubleshooting Differences

Mechanical

• Easier to see system

• Can put your hands on it

• Not much calculation

• Often, small number of

alternatives

Electronic

• Hard to visualize what a

part does

• Black boxes, miniaturized

• May require extensive

calculation

(6)

Troubleshooting Similarities

• Requires knowledgeable troubleshooters

• Systems becoming more complex

• Lines blur between mechanical and electronic

• Must always look at entire system interaction

• Operators are ALWAYS breaking the gear!

Why Does Troubleshooting Fail??

• No formalized process in place

• No one in charge and looking at the Big Picture

• No one knows initial conditions

• No one is sure what has already been done

• Everything performed in series

(7)

Before you start…

• Specify the goals of the troubleshooting

• Have plan in place to:

– Gather initial data

– Notify team

– Preserve the evidence / indications

– Record troubleshooting progress / results

Organizing Your Team

• Man in charge must be:

– Designated and agreed upon

– Equipment expert, but not necessarily the “guru”

– Able to interface with team and management

– Able to see “big picture. Do NOT get pulled into

“weeds” of troubleshooting effort

– Knowledgeable of entire system interactions

– Organized and firm

(8)

Organizing Your Team

• Team may have all or some of the following:

– Expert on the equipment that has failed

– Equipment operator

• May be the one operating the gear when it failed

– Parts procurement

– Data entry / extraction / computer guy

– LO/TO guy

– Runner (“gopher”)

7-Step Process

General Comments

• Write down everything. Do not depend on

your memory.

(9)

In Parallel:

• While waiting for initial steps to be

completed, what can be done?

• Gather maintenance history

• Get technical manual

• Obtain test equipment

• Immediately get observed symptoms from the

operators

7-Step Process

1. Symptom Recognition

2. Symptom Elaboration

3. List of Possible Faulty Functions

4. Localize the Faulty Function

5. Localize the Faulty Circuit / Component

6. Failure Analysis

(10)

1. Symptom Recognition

Immediate Action

• Immediate discovery of the problem by

operator and supervisor

– Who knows?

– Who should know?

– Who must be informed?

– Is equipment in a safe condition?

• Procedure to record problem at operator level

(11)

Troubleshooting Team Arrives

• This is much easier than you think

• Only list

what actually caused the operator to

recognize that there was a fault

• Do not include:

– Operating conditions

– Other indications

• What are goals?

– Repair?

– Restore operation?

(12)

• Operating conditions at the time

– Start-up, shut-down, etc

– Power level, fluid levels

– Special operations in progress

– Recent maintenance

– Anything different than normal

– Exact sequence of switch operation

• Other symptoms noted:

– Alarms

– Warnings

– Blown fuses

– Smells

– Sounds

Include

anything you

think might be

pertinent.

Symptom Elaboration

• Man in charge – Be ready to give options.

– Can we operate in reduced status?

• Lower throughput, less reliable, more likely to break

something else, etc.

– Can we by-pass the failed module (permission?)

– How long to implement each option?

– Risks for each option?

– How long can we operate with each option?

– What additional safeguards should be put in

place?

(13)

Symptom Elaboration

• Don’t operate anything yet

• What permissions do you need to continue?

• This step in the process is where many

troubleshooting plans break down.

– Not all indications are listed

– Operator impressions / observations are not

immediately

obtained

– Nothing is written down

(14)

• List all major functional blocks that could

cause the problem:

– Power supply

– Sensor

– Amplifier

– Etc

• We are not yet looking for the one specific

failed component

Possible Faulty Functions

Don’t

eliminate

anything

unless you

can prove it!

• This is where Equifactor® can be used

– Quickly look through “Symptoms” for problems

available in the tables

– Gives you ideas what possible causes you should

look for

– This is quick method of verifying what you think

could be the cause

– Makes you think of problems outside your

experience

(15)

• You may want to have a Troubleshooting

Guide assembled for most frequent or critical

failures

– Allows you to quickly get to this point

– Could be pulled directly from Equifactor®, or even

maintained in an Equifactor® Custom Table

– Often in quick, flowchart format

Possible Faulty Functions

(16)

Localize Faulty Function

• Actual troubleshooting

• Permissions obtained

• Write down expected

before

you take a

reading

– Prevents “seeing what you expect”

– You’ll talk yourself into whatever you observe

• Write down EVERYTHING you do

– May need to turn over

– Will want to look at it tomorrow

Localize Faulty Function

• Man in charge – Be ready to give further

options.

– More options may be available, now that you

know what major component has failed.

• Replace major function without knowing what exact

component failed?

• What is risk of damaging new part without full failure

mode known?

(17)

Localize Faulty Function

Equifactor® Tables may have

ideas on how this type of fault

was troubleshot last time

• Linear

– Test at each element

– Left to right

– Check input, output, power applied for each

element

Functional Troubleshooting Methodologies

INPUT

Signal

Output

Signal

(18)

• Half-split

– Test each element

– Start in the middle

– Check input, output, power applied for each

element

Functional Troubleshooting Methodologies

INPUT

Signal

Output

Signal

Check

Bad

Check

Good

• Easter Egg

– Used because:

• Not trained in any particular method

• No plan in place, therefore, just get going

• Not sure what has already been done

Functional Troubleshooting Methodologies

INPUT

Signal

Output

Signal

Most

Popular?

(19)

5. Localize Faulty Circuit / Component

Localize Faulty Circuit / Component

• This is troubleshooting to component level

• Troubleshoot down to lowest possible

(expected) level

• May require specialized test gear

• Again, record everything you do

(20)

6. Failure Analysis

Failure Analysis

• Prove to the team that the failure you found

would cause ALL the symptoms you found.

This prevents:

– Replacing wrong component

– Having multiple undiscovered faults

– Talking yourself into your favorite failure

(21)

7. Retest Requirements

Retest Requirements

• What retests will be required to prove the

gear works?

– Prove the new component is good

– Prove there are no other associated faults

– Prove you did not cause other damage during the

troubleshooting or repair

• May be required to officially recertify the

system

(22)

• Correct retests are required to ensure reactor

safety.

– Contained in a variety of manuals.

• Maintenance & Replacement Instructions.

• Equipment Technical Manuals.

• Equifactor® may provide guidance when a specific

retest was used in the past

• Can be researched and pre-approved.

• Agreement on the correct retest requirements is a

combined effort.

Retest Requirements

Plant Relationships

CAUTION:

Actions taken during troubleshooting efforts can

affect various plant capabilities.

(23)

TROUBLESHOOTING RECORD

1. Symptom Recognitio n _______________________________________________ _______________________________________________ _______________________________________________ ________________________________________ _______ _______________________________________________ 2. Symptom Elaboration : _______________________________________________ _______________________________________________ _______________________________________________ _______________________________ ________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________

3. Possible Faulty Functions :

_________________ _ ___________________ _________________ _ ___________________ _________________ _ ___________________ __________________ ___________________ _________________ _ ___________________ List operational options:

Options

Lower reli ability? By-passinterlock? How long to implement? Permission required? List risks AdditionalSafeguards

4. Localize Faulty Function:

Test Point Expected Actual Sat/Unsat

______________________________________ __________________________ _________ ____________ ___________________________________________

Troubleshooters

-! Maint. History ! Plant Operating Manual ! TechnicalManual ! Repair Parts ! Retests ! Area se t-up ! Test Equipment

5. Localize Faulty Circuit:

Test Point Expected Actual Sat/Unsat

___________________________ _____________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ___________________ ________ _________________ ____________________ 6. Failu re Analysis : ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ___ _____________________________________________________________ _________________ _________________________ ______________________ __________________________________________ _____ _________________ ___________________________________________________________ _____ _______________________________________________ __________ _______ 7. Retest Requirements : ________________________________________________________________ ________________________________________________________________ ______________________________________ __________________________ ________________________________________________________________ _______________________________________ _________________________ ________________________________ ______________________________ __ ________________ _____ ________________ ___________________________ _____________________ _____ ______________________________________ ___________________________________________________________ _____

repair lcd

1

1

7-Step Method for

7-Step Method for

Electronic Troubleshooting

Electronic Troubleshooting

Ken Reed

Ken Reed

System Improvements, Inc.

System Improvements, Inc.

238 South Peters Road, Suite 301

238 South Peters Road, Suite 301

Knoxville, Tennessee 37923 USA

Knoxville, Tennessee 37923 USA

Phone: 865-539-2139 Fax: 865-539-4335

Phone: 865-539-2139 Fax: 865-539-4335

e-mail: [email protected]

e-mail: [email protected]

web: www.taproot.com

web: www.taproot.com

Scenario #1

Scenario #1

•

•

You are enjoying a leisurely day by the pool.

You are enjoying a leisurely day by the pool.

Man, it’s hot out here!

Man, it’s hot out here!

•

•

Your wife

Your wife calls from

calls from the kitchen

the kitchen door.

door. “The

“The

thermostat

thermostat for the

for the air conditione

air conditioner is br

r is broke.

oke. It’s

It’s

getting hot in here!”

getting hot in here!”

•

Scenario #2

Scenario #2

•

•

You are the maintenance supervisor at a coal

You are the maintenance supervisor at a coal

mine.

mine. You must m

You must move 600 ton

ove 600 tons / hr ou

s / hr out of the

t of the

mine.

mine.

•

•

You get

You get a call fr

a call from the

om the control ro

control room.

om. “The

“The

conveyor be

conveyor belt is dow

lt is down again.

n again. It just

It just shut off.”

shut off.”

•

•

You have about 1 hour before the hopper is

You have about 1 hour before the hopper is

_{hours left on battery power.}

_{hours left on battery power.}