Testing - Sony KD-34XBR2 Training Manual

4. Adjust HV RV8002 for 35.5kV (shutdown threshold). Use an accurate DVM with HV probe.
5. Adjust RV8001 until the set just shuts down.
6. Turn HV RV8002 CW to turn the set ON. Input a white signal. Bring the HV up to 35kV to make sure the set
does not shut down. (This rechecks the RV8001 adjustments.)
7. Adjust HV RV8002 for 31.5kV.

Testing

1. HV Check - Measuring the voltage at D8025/Cathode verifies HV. Normally D8025/Cathode = 31.6Vdc
when there is HV, and 0V when HV is missing. D8025' s Anode voltage should not be higher than 0.6Vdc
in normal operation (measured). D8025 is located next to the potted (epoxy sealed) RV8001/RV8003
controls at the left edge of the D board. See Figure 9-3 below:
2. HV Converter Check - If no HV is output, look for +200V input at IC8002/pin 18 and more than 15.6V at
IC8002/pin 8.
Look for HV Conv start voltage at IC8002/pin 1 (normally 1.6Vdc but must be more than 1.3Vdc. to start). See
Charts 9-2 and 9-3 below:
Pin
Volts
Pin
Volts
Electrical Location
IC8001/pin 1
IC8001/pin 2
C8004/ + lead
3. HV may be starting, then shutting down - Monitor D8025/Cathode for 31.6V at start up. If it is 0V, there is
no HV. Check the converter transistors and suspect IC8002 and the flyback to cause OCP shutdown (via
Q8009). If the cathode voltage momentarily rises beyond 31.6Vdc, there is HV but it may be excessive.
Turn the RV8001 and RV8003 controls CCW and adjust the HV. Follow the HV adjustment procedure. If
shutdown still occurs suspect D8025, C8005 and D8004.
D8025
Flyback
Chart 9-2 - Converter IC8002 Voltages
1 2 3
1.63 1.75 2.25
10 11 12
10.3 0 4.14
Additional Important Voltages related to IC8002/pin 1 Voltage
Physical Location
14 pin Surface mounted IC under
RV8001/RV8003
Behind IC5515' s large heat sink
next to large 820uf, 250V C8023.
D Bd
FIGURE 9-3 - KD34XBR2 rear
4 5 6
2.47 0 0
13 14 15
0 108 98.6
Chart 9-3
35
9. High Voltage Power Supply
A Bd
7 8 9
4.56 14.7 0
16 17 18
103 0 200
Voltage
0V
0V
0.02V