Sorry for the delay, went camping. Ok performed the test as requested. Neg lead on cap side and pos lead on what we are calling the pos rail side (since the other side seems consistent neg rail voltage). Got +16v for a few seconds, then it dropped out. Removed power from the amp, then tested again. Same results. So I guess that tells us something as we are getting half wave at 16v+.
I guess maybe I misunderstood. are we testing with rectifier out. thats how I did this test. If we are testing with rectifier in, which should I use? Thanks again for your ongoing help. I know some of these things may seem extremely redundant for you. I do similar for people with cars as my profession is car fixing. So its, nice to find someone willing to go through the motions of diagnosis and such.
ok, so putting diode on this side actually created a spark when I soldered it on. No power to amp during this process.
Other diode installed and I just tested to see what that side did in this config and I got no neg rail voltage at all. pos side still consistent with the previous results.
Scope on collector for probe side and use negative input to amp for reference?
Other diode installed and I just tested to see what that side did in this config and I got no neg rail voltage at all. pos side still consistent with the previous results.
Scope on collector for probe side and use negative input to amp for reference?
Im an idiot. I put the diode in backwards on the neg side. Redid the test, have full neg rail power on neg side. also, when testing with power removed, still shows almost normal neg rail voltage, but is dropping as I suspect meter is draining a cap. Pos side shows .6v+ and draining with power removed.
![DSC_1646[1].jpg](/community/data/attachments/817/817183-1dff09dba4d20a9217873a101db86334.jpg)
Are you using the point indicated by the orange arrow for the reference (black meter probe)?
If you leave the scope connected to the collectors of the PS transistors, how long do you see oscillation after applying remote voltage?
Scope ground to the primary (power) ground.
Sorry, half asleep.
If you leave the scope connected to the collectors of the PS transistors, how long do you see oscillation after applying remote voltage?
Scope ground to the primary (power) ground.
Sorry, half asleep.
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![DSC_1646[1]dsf.jpg](/community/data/attachments/817/817235-7789aa19394e2464c8d8d418a8131368.jpg)
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Maybe you forgot to upload a pic? In the bottom right hand corner of my pic, there are three joined traces. Right side is pos rail, next going to the left is where the two caps join and the black wire heads out to the audio board, and left side is is neg rail.
scope connection: ground lead to what? do you mean emitters when you say drains? Right now in its present configuration, at least at the rail voltages, I dont see any oscillations. everything is steady. Solid pos rail and solid nothing really on neg side.
scope connection: ground lead to what? do you mean emitters when you say drains? Right now in its present configuration, at least at the rail voltages, I dont see any oscillations. everything is steady. Solid pos rail and solid nothing really on neg side.
No worries! So, I switched to the CRT scope since the LCD isnt really great to read. One of the collectors on the PS transistors shows a really nice sine wave a second or so after adding power. The other one does show an irregular sine wave, then stabilizes, then starts to be erratic after maybe 5 seconds or so. The erratic behaviour is not consistent though.
also double checked with the meter to see since at one point during this test, both PS transistors were showing a good waveform. still nothing on the neg side and 33+ on the pos side. But the scopemeter does both at the same time and I happened to compare them. The scope on the meter shows an AC signal when checking for neg dc rail voltage at the aforementioned test points. The pos rail voltage is a clear DC pos signal.
also double checked with the meter to see since at one point during this test, both PS transistors were showing a good waveform. still nothing on the neg side and 33+ on the pos side. But the scopemeter does both at the same time and I happened to compare them. The scope on the meter shows an AC signal when checking for neg dc rail voltage at the aforementioned test points. The pos rail voltage is a clear DC pos signal.
Yes, that is correct. Just noticed it seems I have a dirty pot on my CRT scope, so that was throwing me off a little last night.
One other thing I should probably mention is how I am turning the amp on. I dont know if it matters though. I have the constant power and remote jumpered and I am adding the ground to turn it on.
One other thing I should probably mention is how I am turning the amp on. I dont know if it matters though. I have the constant power and remote jumpered and I am adding the ground to turn it on.
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