With some amps, applying both B+ and remote together can cause problems. If it doesn't with this amp, it's OK.
For the negative diode, move the end that goes to the transformer to the same transformer winding as the positive diode. Does that give you both positive and negative voltage on the caps?
Are there any broken wires or solder connections on the transformer windings?
For the negative diode, move the end that goes to the transformer to the same transformer winding as the positive diode. Does that give you both positive and negative voltage on the caps?
Are there any broken wires or solder connections on the transformer windings?
Well it did get me thinking that caps might be a thing by removing the ground. I will reconfigure the setup for turning it on.
Still not reconfigured though, yes that give me 33v both pos and neg with reference of negative test lead on the caps.
I cant see anything on the transformer that indicates open circuit or anything.
Still not reconfigured though, yes that give me 33v both pos and neg with reference of negative test lead on the caps.
I cant see anything on the transformer that indicates open circuit or anything.
If only one transformer winding (of the two that went to the AC of the bridge rectifier), it would seem that one winding either has bad connections or a broken wire.
Heat all of the solder connections for all of the various transformer windings to see if the wires for any just fall over when thoroughly heated.
Heat all of the solder connections for all of the various transformer windings to see if the wires for any just fall over when thoroughly heated.
This seems like we are getting closer. Hope its not the transformer, those probably arent easy to find.
I did heat them all and nothing obvious changed. Retouched the solder connections and no change there either. Next step is to pull it from the board and test on the bench for resistance then, I assume?
I did heat them all and nothing obvious changed. Retouched the solder connections and no change there either. Next step is to pull it from the board and test on the bench for resistance then, I assume?
I don't know how clearly the windings are laid out. If they're confusing, try to check them with resistance.
What's the resistance between the two windings that feed the AC terminals of the bridge rectifier?
Between those windings and the ground between the filter caps (orange arrow)?
What's the resistance between the two windings that feed the AC terminals of the bridge rectifier?
Between those windings and the ground between the filter caps (orange arrow)?
They arent too confusing, but the schematic we are going with isnt exact on this portion from what I can decipher.
resistance between the two points of AC input to the bridge rectifier are about an Ohm.
same resistance between orange arrowland and those same points as mentioned above.
resistance between the two points of AC input to the bridge rectifier are about an Ohm.
same resistance between orange arrowland and those same points as mentioned above.
Using the ground between the capacitors, do you have a square wave on both AC terminals for the bridge rectifier?
Are they the same amplitude?
Are they the same amplitude?
This is confusing. The bridge rectifier, if intact, was pulling from both windings but never produced the positive rail. The individual diodes will produce both rails if pulling from one winding but not from the other, even though both windings have the same waveform.
Do you have a 120v incandescent (not CFL, not LED) lamp (lower power would be better)?
Do you have a 120v incandescent (not CFL, not LED) lamp (lower power would be better)?
Right?? Very confusing and likely my fault for not getting all of this. Of note, not on all tests until recently have I been screwing the PS transistors to the heat sink. So maybe that matters?
I do have a 120vac 25w incandescent bulb here that I used earlier.
Maybe since I have all three wires disconnected from the PS to audio board, I might try installing the OG rectifier and testing with both transistors screwed down? If them being screwed down is the issue, I feel like a total idiot.
I do have a 120vac 25w incandescent bulb here that I used earlier.
Maybe since I have all three wires disconnected from the PS to audio board, I might try installing the OG rectifier and testing with both transistors screwed down? If them being screwed down is the issue, I feel like a total idiot.
Are there insulators under the PS transistors?
Connect one end of the lamp to the 'orange' ground.
Touch the other end of the lamp to both points where the secondary windings come through the board. Monitor the current draw, does the current increase the same for both windings?
Connect one end of the lamp to the 'orange' ground.
Touch the other end of the lamp to both points where the secondary windings come through the board. Monitor the current draw, does the current increase the same for both windings?
There are no insulators. There werent any originally either. All test since last weekend have been with them screwed down since you mentioned that.
Light bulb test is the same test I just did with the scope but with a light bulb, correct?
Light bulb test is the same test I just did with the scope but with a light bulb, correct?
The scope draws no current. The lamp may produce different results.
There should be insulators under the transistors if the collectors drive the transformer windings. Do you have any insulators, of any type?
There should be insulators under the transistors if the collectors drive the transformer windings. Do you have any insulators, of any type?
My mistake again. The paste threw me off. Yes, both have insulators.
Proceed with light bulb test then with transistors screwed down?
Proceed with light bulb test then with transistors screwed down?
If there are (intact) insulators under the transistors, having them screwed down won't make a difference as far as the transistor's operation is concerned. You can look at the waveforms on the transistor collectors when loose and when screwed down to see if they change, to make sure there is no difference.
Ok light bulb test illuminated the bulb and the ammeter on the power supply seemed to move the same amount. light bulb lit up about the same lumens, I would guess. So, I guess that means the transformer is ok then?
Just for double checking and I put the diode for the neg side back on that seemingly nonfunctional side of the AC input and now I have both pos and neg 33v..
On the audio board, measure the resistance from the pad that the 'orange' ground was connected to to the other two pads that were fed with the positive and negative rail.
What do they read?
What do they read?