disconnect all loads from the PSUs.
Charge up the PSUs to full voltage.
Take a measurment to confirm they both come up to the same or very similar voltages.
Re-charge to full voltage. Do not take any measurements.
leave them to soak for 48hours.
Then quickly take Voltage measurments. See how much they all vary.
Taking a measurement takes some charge out of the capacitors.
Taking many measurements will significantly change the voltages you are trying to prove are equal, or unequal.
Good electrolytic capacitors will very slowly discharge over a period of many days. Expect them to hold a significant voltage after 30days and even after 60days !
Charge up the PSUs to full voltage.
Take a measurment to confirm they both come up to the same or very similar voltages.
Re-charge to full voltage. Do not take any measurements.
leave them to soak for 48hours.
Then quickly take Voltage measurments. See how much they all vary.
Taking a measurement takes some charge out of the capacitors.
Taking many measurements will significantly change the voltages you are trying to prove are equal, or unequal.
Good electrolytic capacitors will very slowly discharge over a period of many days. Expect them to hold a significant voltage after 30days and even after 60days !
Fully agree.
"Holding charge" is not a defect but a virtue, focusing on the main capacitors is WASTING time, rather check what EXTERNAL load is not pulling current.
They do not "behave different", quite the contrary, they are being USED different.
"Holding charge" is not a defect but a virtue, focusing on the main capacitors is WASTING time, rather check what EXTERNAL load is not pulling current.
They do not "behave different", quite the contrary, they are being USED different.
Yeah, that will be a waste of time and money for sure.
Have you tried measuring the current draw? Do you have a meter capable of measuring it? Do you know how to measure it?
I don't think caps are the problem, I think you've either got a bad connection or a bad semiconductor somewhere.
You could disconnect capacitors from the circuit and connect a 1k resistor across each one. Turn it on, then turn it off and monitor how long each cap takes to discharge.
It should take RC time to discharge to 1/3 of the original volts.
I have a cheapo LC meter for caps.
It should take RC time to discharge to 1/3 of the original volts.
I have a cheapo LC meter for caps.
Didn't get notifications until today(?)
I figured worst case I'd have a couple of good caps lying around, which does appear to be the case although I've had slight progress
1 min after power off I get readings of 1vDC on the R and 14vDC on the L (not 43.5)
after 5 min, read 0.7vDC R and 12vDC L. I also get 12vDC from C406 (L) vs 0.55 for C405 (R).
Checked again after being off for 2 hours and C9/10 had 3vDC and that is mirrored in C406 (3vDC).
If I power on with 3vDC in C406 the Slow Start works for about 2 secs and I get 9vDC peak dropping to 15mV in about 45 secs.
With 6vDC or more still in C406, the Slow Start does not work at all and I get up to 32vDC to the speaker terminal dropping to 15mV in about 60 secs.
With C9/10/406 reading less than 0.5vDC the Slow Start works as it should and I see 1vDC or less while its dropping to 15mV in about 30 secs
So I know what the problem is, I have no idea why C9/10/406 aren’t draining or what should normally drain C9/10/406.
Not sure how to check current. My MM is not the worst and does have a 20A setting. Would I measure it live or off?
I figured worst case I'd have a couple of good caps lying around, which does appear to be the case although I've had slight progress
1 min after power off I get readings of 1vDC on the R and 14vDC on the L (not 43.5)
after 5 min, read 0.7vDC R and 12vDC L. I also get 12vDC from C406 (L) vs 0.55 for C405 (R).
Checked again after being off for 2 hours and C9/10 had 3vDC and that is mirrored in C406 (3vDC).
If I power on with 3vDC in C406 the Slow Start works for about 2 secs and I get 9vDC peak dropping to 15mV in about 45 secs.
With 6vDC or more still in C406, the Slow Start does not work at all and I get up to 32vDC to the speaker terminal dropping to 15mV in about 60 secs.
With C9/10/406 reading less than 0.5vDC the Slow Start works as it should and I see 1vDC or less while its dropping to 15mV in about 30 secs
So I know what the problem is, I have no idea why C9/10/406 aren’t draining or what should normally drain C9/10/406.
Not sure how to check current. My MM is not the worst and does have a 20A setting. Would I measure it live or off?
The most likely outcome from changing capacitors which are not faulty in order to fix a fault which lies elsewhere is that nothing will change. The next most likely outcome is that a new fault will be introduced. So please forget about changing caps until you have some solid evidence that the caps are faulty.
Debugging a typical solid-state amp is not always easy for those with knowledge, experience and familiarity with test equipment. This is because the whole circuit is usually DC coupled so a fault anywhere can cause symptoms everywhere. Debugging will be harder (and almost certainly very frustrating) for anyone else.
Start by measuring current draw. If this is beyond you then repairing this amp is beyond you. Sorry to be blunt.
Debugging a typical solid-state amp is not always easy for those with knowledge, experience and familiarity with test equipment. This is because the whole circuit is usually DC coupled so a fault anywhere can cause symptoms everywhere. Debugging will be harder (and almost certainly very frustrating) for anyone else.
Start by measuring current draw. If this is beyond you then repairing this amp is beyond you. Sorry to be blunt.
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