Philips CDR600/00/17 Service Manual page 54

GB 50 8. CDR600
TROUBLE SHOOTING POWER SUPPLY
+5V +12V -8V VFTD(-38V) VDC1-VDC2(3V8)
Disconnect the power supply from the MAIN Board
Connect a dummy load resistor 6,8 ohm 10W (min 5W)
+5V +12V -8V VFTD(-38V) VDC1-VDC2(3V8)
connect the mains inlet to a mains
turn input voltage up and check across
C2121 the voltage
this voltage should be +/- 1,41 x Vin ac
is power supply ticking?
check Vcc on pin 7 IC7110
Vcc = 12V...... 16V
check oscillator on pin 4 IC7110
is the osc +- 30kHz working ?
check the voltage on the source of 7125
Vsource = 1,3V ?
Disconnect diode 6150
start variac from 0V and turn-up slowly
measure the 5V output
If the 5V becoming higher than 5V, the regulator
circuit are damaged
After the power repaired check the 3,3V
Faultfinding Guide
Check DC voltages
NOK
on the 5V and
Check DC voltages
NOK
OK
Check the +5V
NOK
OK
isolated variac
OK
NO
OK
OK
NO (Vsource = +- 0.8V)
5V OK
OK
power supply OK
power supply OK
OK
check - main board
- front board
- modem board
check the fault voltage path
check 6210-2210-2253-5210
NOK
check the functionality of the following components:
1120-2121-2125-2126-2127-6102-7125
YES
check the load on the secundairy output
check overload circuit 6141-7141-7150
NOK
check 2121-2133-2134-3123-3134-6130-6132
replace 7110
NOK
check 2102 - 3102
replace 7110
check 3125-3126-3127-3128
YES
replace 7125
check:3201-3202-3203-3204-3205
3206-3207-3208-7131-7201
5V NOK
replace 7110
check circuit around Ic7110