Ok cool. Will do tomorrow. While I do want to fix this amp, I also want to understand what I am doing/learning here. If you have time, can you explain what this test does? Again, I really appreciate you taking the time to help me out.
I want the lamp to try to drain the cap to see if it's being charged by a pulse or to see if the supply is actually functioning.
The current draw is another way to see what's happening with the supply.
The current draw is another way to see what's happening with the supply.
Ok, hooked up a standard 120vac light bulb (25w) in parallel to the points of testing in question. Got 3mV to start and it kept dropping. Ammeter on power supply made a brief tick up to about 3-4a and then dropped back down. removed the light bulb from teh circuit to double check and it still reads -33v like before. So I guess we learned something from this? Power supply inop? It has to be doing *something* since I get audio, but maybe its not providing enough current to sustain feeding the output ICs?
Prior to removing the ICs, it would give some audio, but cut in and out. So, unless something has changed, I would think the power supply side is doing something rather than nothing.
Where did you get the second bridge rectifier?
Is the rectifier installed so that the AC terminals are connected to the windings from the transformer?
Is the rectifier installed so that the AC terminals are connected to the windings from the transformer?
replacement one came from West Florida Components. Not sure how reputable. I did use the diode check on the meter to test both new and the old and both are giving the same readings out of the circuit.
Is the rectifier installed so that the AC terminals are connected to the windings from the transformer?
Yes. There is even a trace drawing on the board that shows the marked corner to match it will so it is installed in the correct orientation.
do you mean remove the rectifier and put both one probe on each side of the AC input to the rectifier?
Something wonky. Just checked it again with scope and got waveform. Went back to meter mode and we are reading a consistent 66vac. Aside from a bad new rectifier, any other idea that could explain this?
I should also note here, this is the rectifier that was original to the amp:
RB 60, Tube RB60; Rohre RB 60 ID66575, Solid-State-Diode
This is the replacement I got based on the 600V 8A spec. So, its possible I got the wrong part? It is dimensionally smaller, but the package design and pin configuration is the same.
8A 600V Single Phase Silicon Bridge Rectifier TCI BR86
RB 60, Tube RB60; Rohre RB 60 ID66575, Solid-State-Diode
This is the replacement I got based on the 600V 8A spec. So, its possible I got the wrong part? It is dimensionally smaller, but the package design and pin configuration is the same.
8A 600V Single Phase Silicon Bridge Rectifier TCI BR86