Hi
Background:
This unit suffered from high voltage, 27 V, on the surround Left channel. This triggered the protect circuit, as its supposed to, after start up.
After disassembly I checked the Power transistors Sanken B1560 and D 2390 and measured all channels. Found one B1560 broken.
Also the corresponding large dual ceramic resistor 0.27 Ohm had one resistor shut.
Problem:
Even though the 27 V offset value has been reduced I still have DC Offset on nearly all, including the one repaired. Occasionally the protect mode hits in.
Here is my measured values:
Center 2.7 V
Surr L 2.7 V
Surr R 1.3 V
SBL 0.117 V
SBR 0.0286 V
Front L 0.5 V
Front R 1.297 V
Service manual do not cover DC offset and I cant find any obvious reason why the values diverge this much. Other than having to change all transistors, is that really necessary?
Background:
This unit suffered from high voltage, 27 V, on the surround Left channel. This triggered the protect circuit, as its supposed to, after start up.
After disassembly I checked the Power transistors Sanken B1560 and D 2390 and measured all channels. Found one B1560 broken.
Also the corresponding large dual ceramic resistor 0.27 Ohm had one resistor shut.
Problem:
Even though the 27 V offset value has been reduced I still have DC Offset on nearly all, including the one repaired. Occasionally the protect mode hits in.
Here is my measured values:
Center 2.7 V
Surr L 2.7 V
Surr R 1.3 V
SBL 0.117 V
SBR 0.0286 V
Front L 0.5 V
Front R 1.297 V
Service manual do not cover DC offset and I cant find any obvious reason why the values diverge this much. Other than having to change all transistors, is that really necessary?
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