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820 Left channel distortion

Nuklhed said:
..did you mean TR706 in the other channel?
Click to expand...
I meant.. Measure the emitter , base and collector voltages of TR705 and TR706 them post the two sets of voltages. Using TR706 as reference (good channel )
 
TR705
Base -48.6vdc
Collector -48.1vdc
Emitter -48.8vdc

TR706
Base -45.5vdc
Collector -44.8vdc
Emitter -46.5vdc

Tried something over the weekend. Plugged in the headphones. Distortion goes away in the headphones if either the speakers are disconnected; or connected but deselected with buttons on front.

I also had a spare set of output transistors. Put them in the left channel.....no change.
 
Tap firmly on the protect relay while listening for distortion.
 
Maybe invest in a can of freeze spray. Give TR705 a shot then TR707(LG??), note any effect on distortion
 
Avionic….protection relay was original, replaced with new. No change in distortion.

Thanks mbz, I’ll give it a try.
 
Well guys, no joy so far, but I had to pack up the 820. Momma and I are leaving the Peoples Republic of New York. We are taking our guns and our copy of the Constitution and heading to South Carolina. Thanks so much for your help. I will be back when we get settled and I can get back to the bench.
 
Hey friends! Got all moved in down here in beautiful South Carolina! Got the new lab set up and running. Kinda frustrated with the 820 and decided to take a break from it. Also been given 840, 1040 and a basket case 1020 to tackle, so gonna get started with recap/revamp/refurb of the 1040. Works and sounds great so I have fingers crossed that it will be a smoothy. As always, any and all advice is welcome! Great to be back!
 
So…as I worked on recapping the 840’s, 1040’s, 1020’s, I could sense the 820 mocking me from high on the “back burner”. Hooked it up and turned it on. Comes out of protection immediately. Static even with volume down. No left channel at all unless I move the loudness control all the way to flat?? Checked idle voltages. Normal and adjustable on right channel. Zero and adjustment has no effect on left side. The mystery continues. Any thoughts?
 
Need help. Currently experiencing this exact, left channel distortion. Ive already recapped and set idle bias both channel to 8mV. Both pod response when turning. Ive mirror Super Noob rebuild thread. All new transistors and caps. Even new output transistors. Not sure where to start. I have not change out the relay, yet. Distortion start at the 5 mark in the volume. Right channel is perfectly fine.

Well. Did something dump. Was probing TR707 and probe touch something. Blew out the 4a fuse. Replaced and immediately blew again. Should’ve place it on dim bulb after first fuse blown. Put the original output transistors back. Power up on the dim bulb and it glow, not bright but not dim. Relay also did not kick in. So i made another mess on top of the distortion issue. Great!
Help?
 
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