Onkyo Integra 8067 blowing fuses

[tgferg67]

Hi,
I am open to suggestions.
I have an Onkyo Integra 8067 integrated amplifier from the
mid 80's that is blowing the main fuse every 5 minutes - no speakers conncted and volume down. The right channel power transistors are hot to the touch, while the left are pefectly cool by the time the fuse blows. I unsoldered the right channel power transistors and the fuse does not blow when the amp is turn on. The right channel power transistors still check out ok with diode check on the multimeter. All the power transistors on the driver board check out also.

About a year(500 hours) ago a similar situation with blowing fuses - the right channel power transistors were shorted so I replaced all and everything seemed well so I also recapped and adjusted bias.




Photo of power supply/driver boards

[bekim]

Originally posted by tgferg67

The right channel power transistors are hot to the touch, while the left are pefectly cool by the time the fuse blows.

Hi

I had similar problem long time ago, check for biasing diodes might lost values - it is showing very low mV in your dmm. As well, you need service manual to check the idle current.

[tgferg67]

Thankyou for your help. I replace the varistors and now I have a working amp instead of a boat anchor