Okay back at it, all switches cleaned as good as I think I could get, spray and exercise and repeat. This is what I am seeing for channel 1 and channel two. Any quick suggestions by chance? Think I will just start following the signal again but this definitely looks ugly and not stable!
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As if it was not obvious I connected it to my "don't care much about" speakers and all of that is audible, a ton of noise..
I am going to start looking at some of the other components along the signal path like resistors I guess, taking this from a learners approach since I know not much at all 🤓
Also, wondering if these old sockets are just worn out or corroded beyond cleaning?
I am going to start looking at some of the other components along the signal path like resistors I guess, taking this from a learners approach since I know not much at all 🤓
Also, wondering if these old sockets are just worn out or corroded beyond cleaning?
Pay extra attention to the "phase reverse" switch; these have sat unused for more than half a Century, and are required to carry coupla-amps level signal. After the drama has died down, they should IMO be bypassed. Hook up your test speakers, play a little music through, and keep working that switch until it behaves.
I've been talking to the Pope re Canonization for a certain DIYAudio personality - looks likely.
All good fortune,
Chris
I've been talking to the Pope re Canonization for a certain DIYAudio personality - looks likely.
All good fortune,
Chris
Thank you, I was actually looking at that switch and the balance check switch, they both see not relevant and look to be easily bypassed as well. But I agree, there is more going on here but I think definitely things to consider. And I agree, for all I know this unit just sat, it was a mystery unit no info at all. Thank you, I think it would be a bad idea to do a round 2 on the cleaning of the switches and pots!
This amp is possessed. I did nothing except let it sit off for a while and fired it back up and this, and, it has been on now for a while and everything still seems stable. Only issue i see is the balance is off at certain volumes, second photo. The scope is displaying C1 and C2.
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I should have said "unmoved" rather than "unused". Their contacts have been sitting in the oxygen atmosphere (that we mammals love so much) for a long time, without any wiping action to burnish to a non-oxidized surface. They need some physical attention in addition to chemical.
All good fortune,
Chris
All good fortune,
Chris
Have all pots (bias, volume, balance, tone, etc.) and switches (slide, rotary, etc.) been properly cleaned
and exercised repeatedly? If not, do it now. If yes, do it all again. The 60 years of oxide, smoke, and crud
must be broken through. There's no point in proceeding unless all this has been done.
And use only the best probes that you have with the scope.
The balance control is just a variable resistor, and is set by measurement at the point where both channels are equal.
The mechanical position of the knob is not relevant to that.
and exercised repeatedly? If not, do it now. If yes, do it all again. The 60 years of oxide, smoke, and crud
must be broken through. There's no point in proceeding unless all this has been done.
And use only the best probes that you have with the scope.
The balance control is just a variable resistor, and is set by measurement at the point where both channels are equal.
The mechanical position of the knob is not relevant to that.
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Hi again! Yes they have but yes I think you are right, it needs probably a week of exercising and cleaning. I do notice that even when the trace looks good and I move switches or knobs it has a large affect on what I see on the scope. I just order another can of D5!! Also, if I may ask, do you think the issue with the balance when I raise and lower the volume is again with the pots or could that be something else?
Thank you again, I am shocked I never thought that these connections and pots would be such a burden but as we go through all of this It really makes sense now!
Thank you again, I am shocked I never thought that these connections and pots would be such a burden but as we go through all of this It really makes sense now!
Think about a car made in the 60s that you found in a barn.
Would you expect it to start right up and drive down the road like new?
Or would it have to be completely rebuilt?
Would you expect it to start right up and drive down the road like new?
Or would it have to be completely rebuilt?