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