6-43. Keyboard test
1. CPU communication errors
6.4 Guidelines for troubleshooting
Remarks) Before starting inspection :
1. Confirm that the input voltage is DC 21.6 - 31.2 V.
2. Check the cable connection with external devices and connectors in the main unit.
3. Practice self-test.
A high voltage is applied in the apparatus. When checking inside, be sure to turn off the power supply.
Warning
1
2
Power is not turned on.
Transmitting output is much reflected.
1. The power input voltage is too low (less than 18 V), or too high (more than 32 V).
2. The power breaker is off.
3. The power circuit board is defective.
Confirmation)
• Check the power switch.
• Check the output voltage. (+15V) 4. The output lines from the power board (+15 V)
is short-circuited.
Confirmation)
• Disconnect external devices.
• Disconnect the power supply connectors in the main unit one by one.
1. The coaxial cable connector of the transmitting ANT is defective.
2. The coaxial cable of the transmitting ANT is defective.
3. The transmitting ANT is defective.
Confirmation)
• Replace it with the receiving ANT and compare.
4. Location of the transmitting ANT is bad.
Confirmation)
• Check whether the location is close to other structural objects or not.
Adjust it to the specified value.
Check the breaker on the rear of the main unit.
Exchange the power board.
Repair the short-circuited portion, or exchange the short-circuited board.
Check bad contact of the coaxial cable connector and soldering. Rectify them.
Check any leak of water.
Exchange the cable, if any.
Exchange the ANT.
Change the location of antenna.
Possible causes Remedies
Symptoms No.
The mark * indicates a NG or error message in self-test.
3
4
5
6
The difference in output power is big between DUP and SIMP
* DX-8700 : NG
* TRANSMIT POWER : NG
The transmitting range is short.
The transmitting power does not output.
Modulation does not work.
1. Main unit handset 2. Wing handset 3. Remote 4. DSC
1. The duplexer is defective.
Confirmation)
• Check that the difference in power data between DUP and SIMP is less than 100.
2. The duplexer switching circuit is defective (bad contact of K1 and K2 of CH70 RX board).
1. The transmitting power is low.
Confirmation)
• Check that the power is the rated value of 25 W.
* TRANSMIT POWER : NG 2. The power loss in DX-8700 is big.
Confirmation)
• Compare the transmitting output from the main unit and that from DX.
* DX-8700 : NG
3. The transmitting PA module IC (U1: M57710A) is defective.
* TRANSMIT POWER : NG
4. The Location of the transmitting ANT is bad.
1. The transmitting synthesizer PLL circuit is defective.
Confirmation)
• Check that the CR11 on the TX board is off, UN-LOCK. (TX PCB: PLL Lock)
2. The PA IC module or the transmitting amplifier circuit is defective.
* TRANSMIT POWER : NG 1. The main unit handset is faulty, or the
modulating circuit on TX board is defective.
Confirmation)
• Check, with line monitor function, whether the signal is coming in or not.
2. The wing handset is faulty, or the modulating circuit on TX board is defective.
Confirmation)
• Check, with line monitor function, whether the signal is coming in or not.
• Check the MIC SELECT circuit on CONTROL board with carbon and dynamic microphone.
3. The remote station RB-700 is faulty, or the modulating circuit on TX board is defective.
Confirmation)
• Check, with line monitor function, whether the signal is coming in or not.
4. The CONTROL board is faulty, or the modulating circuit on TX board is defective.
Confirmation)
• Check, with line monitor function, whether the signal is coming in or not.
Exchange the duplex unit.
Exchange the CH70 RX board.
Adjust the power. (Refer to
"Setting PO" in Chapter 3
"System setting".)
Check about Symptom 2.
Exchange the PA module or the TX board.
Check about no. 4 in Symptom 2.
Exchange the TX board.
Exchange the TX board.
Exchange the main unit handset, or exchange the TX board.
Exchange the wing handset, or exchange the TX board if the monitoring is possible.
Exchange the RB-700, or exchange the TX board if the monitoring is possible.
Exchange the CONTROL board, or exchange the TX board if the monitoring is possible.
Possible causes Remedies
Symptoms No.
6-10
Receiving sensitivity is bad.
Receiver noise does not come out if SQ is OFF.
Remark) SQ is not AUTO.
Receiving on CH70 is bad.
* DSC cannot be received.
Keyboard does not work.
Remote function does not work.
* VHF is controlled through DSC.
Printer does not work.
1. The receiving ANT system is faulty.
Confirmation)
EReplace the transmitting ANT with the receiving ANT and compare in the same manner as no. 1, 2, 3, 4 in Symptom 2 . 2. The duplexer is defective if DUP and SIMP
channel is different in receiving sensitivity.
3. The receiving circuit is faulty.
1. The receiving AF amplifier circuit is defective.
Confirmation)
• Check it with EXT SP.
• Check it with handset SP.
• Check it with INT SP.
2. The audio volume is defective.
3. SQ circuit is faulty. SQ volume is defective.
4. The receiving synthesizer PLL circuit is defective.
Confirmation)
• Check that the CR2 on the RX board is off and UN-LOCK.
* RX PCB: NG
1. The receiving ANT system is faulty.
Confirmation)
• Replace the transmitting ANT with the receiving ANT and compare in the same manner as no. 1, 2, 3, 4 in Symptom 2 . 2. CH70 RX board is defective.
Confirmation)
• Practice self-test.
* CH70 RX PCB: NG
1. The panel board or CONTROL board is defective if all keys do not work.
2. The panel board is defective if specific keys do not work.
Communication between the CPU for VHF and the CPU for DSC is faulty.
TYPE 1: No change to in TYPE 2: No ack/time out TYPE 3: No initialization
Refer to Section 6.3 "Error messages"
Main unit, the printer, or IF-8500 is defective.
Confirmation)
Remedy as Symptom 2.
Exchange the duplexer.
Exchange the RX board.
Exchange the RX board if no noise comes out in all cases.
Exchange the audio volume.
Exchange the RX board.
Exchange the SQ volume.
Exchange the RX board.
Remedy as Symptom 2.
Exchange the CH70 RX board.
Exchange the panel board or CONTROL board.
Exchange the panel board.
Clear the RAM and EEROM, and if the function does not recover, exchange the CONTROL board.
Refer to Section 5.5 "NMI switch" for clearing RAM and EEROM.
Exchange the CONTROL board.
Possible causes Remedies
Symptoms No.
*
1 2