Panasonic KX-G8300 Service Manual And Technical Manual page 65

LO Get Rite)
If the signal at CN802 pin 3 is generated and the signal at the emitter of Q802 is not present,
the trigger circuit (Q801~Q802) may be faulty.
iii) If the signal at the emitter of Q802 is present, the SCR or pulse transformer may be faulty
Troubleshooting Step 7:|Echos appear but low sensitivity.
Causes
© Trouble in MIC 5V regulator (IF amplifier Q6)
o = MIC failure
fe) End of magnetron's service life
Checks and Repairs
1)
Check that the voltage at connector to MIC pin 4 from the IF amplifier is 5V +0.2V.
If it deviates greatly from 5V, the power regulator Q610 circuit may have failed.
2) Check the magnetron cufrent using the procedure in troubleshooting step 6-(1). If there is a
problem, the magnetron may have reached the end of its service life and should be replaced.
3) Check the voltage at MIC pin 3 (MON).
The MIC has failed if it is not 50 mV +20 mV.
Troubleshooting Step 8:| No change in range with range Up / Down Key (Ranges).
Possible Causes
° Improper connection of connector CN6 on the processor board
© ~~ Control board failure
Checks and Repairs
1) Check the connector CN6 connections on the processor board.
2) Use an oscilloscope to check the signals at pins 8 and 9 of connector CN6 on the processor board
(100 Hz, 5Vp-p pulse train). If the signal does not appear, the processor board has failed.
3)
Use an oscilloscope to check the signal at pin 6 of connector CN6 on the processor board. Check
that a pulse train (approx. 100 Hz, 5Vp-p) appears while the key is pressed. If it does not appear,
the contro! panel has failed.
Troubleshooting Step 9:|No A.C. Sea operation.
Possible Causes
re) Improper connection of V203 control
ce) Improper connection of CN157 on preset board
ce) IF amplifier A.C. SEA circuit Q609 failure