Troubleshooting; Main; Power - JVC TH-A25 Service Manual

5.1

MAIN

5.1.1 POWER

Check for VCC(5V)
at FRONT PCB
;pin #17,46,72,90 of UIC1
Check for power-sense(5V)at FRONT PCB
;pin #77 of UIC1
When power on for FRONT PCB
Check for High Voltage(5V) at"M"com
;pin# 74 of UIC1
Check low Voltage(0V)
at EXPAND IC (M66010)
;pin #32 of UIC500
Check for connector from DSP PCB to FRONT PCB
;VCW7
1-14 (No.MB141)

TROUBLESHOOTING

NO
YES
NO
YES
YES
YES
SECTION 5
Check for Input voltage
at POWER PCB
;AIC1(7805)
YES
Replace AIC1
Check normal Voltage
POWER PCB
at
AZD1 (5.1V, 1/2W)
YES
Check pattern from VCW7
to pin #77 of UIC1
NO
Replace Micom(UIC1)
NO
If High Voltage (5V), check for Circuit protection
Check connector wire Ass'y of power
P/T - MAIN PCB(7P,ACW3)
MAIN PCB (8P,PW3)
NO
Check for circuit at Sub Trans
;PBD2, PT1, AFS3(Fuse)
Replace AZD1
NO
Check resistant from GND
to pin #77 of MICOM(UIC1)
if the short(0 ohm),to replace
Micom(UIC1)