Hypersport
Account deactivated by request of user after tantr
Does anyone have an answer to what is going on internally in a standard switching power supply when the voltages start to skew? For example, I've got a PS that used to be OK (when adjusting +5V output, +12 was about 12.30V with game board attached). Over time, that gap has increased - 6 months ago if I set +5 correctly, +12 would be at 13.89 Volts, and now, if I set my +5 to +5, my 12V is at 14.99. Different game boards produce similar results, so not a game board issue.
I opened up the supply and found 5 bad caps with my ESR meter. A few were bulging as well and I replaced all 5 caps. I was hoping the repair would fix it, but nothing has changed what so ever. If I adjust +5 to 5.00, +12 is still at 14.99. So if not bad caps, then what else is failing here to cause this? The caps replaced were the biggest ones - 2 x 3300MFD 16V, 2 x 1000MFD, 25V, and 1 470MFD, 25V.
Also, the high +12 voltage is causing distortion on my monitor -- if I turn it back down to 12.0 volts, that distortion goes away (although at 12.0V, my +5 is at 3.89 Volts). I did manage to get one board to run with this setting - a Mega Zone.
I actually have the same problem with several other supplies. In fact, I have about 10 -- now I know I can purchase a new one real cheap, but that doesn't help me today. And, if I can get by with making some working ones out of my 10 bad ones, then that's money saved, and trash parts put to good use.
So, if has anyone been down this road and understands the failure and can explain why the new caps didn't fix the problem, I'd love to hear from you.
I opened up the supply and found 5 bad caps with my ESR meter. A few were bulging as well and I replaced all 5 caps. I was hoping the repair would fix it, but nothing has changed what so ever. If I adjust +5 to 5.00, +12 is still at 14.99. So if not bad caps, then what else is failing here to cause this? The caps replaced were the biggest ones - 2 x 3300MFD 16V, 2 x 1000MFD, 25V, and 1 470MFD, 25V.
Also, the high +12 voltage is causing distortion on my monitor -- if I turn it back down to 12.0 volts, that distortion goes away (although at 12.0V, my +5 is at 3.89 Volts). I did manage to get one board to run with this setting - a Mega Zone.
I actually have the same problem with several other supplies. In fact, I have about 10 -- now I know I can purchase a new one real cheap, but that doesn't help me today. And, if I can get by with making some working ones out of my 10 bad ones, then that's money saved, and trash parts put to good use.
So, if has anyone been down this road and understands the failure and can explain why the new caps didn't fix the problem, I'd love to hear from you.
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