Hi Tim! 25.07.2015 00:41, Tim E. Real пишет: > On July 22, 2015 03:26:48 PM Andrew Deryabin wrote: >> I think it's over-voltage (power supply was also broken). > Hiya! > > Hopefully it was not AC input over-voltage (storm surge etc.) It can be so, because before broken ATX power supply there was an PCM UPS which was also damaged. I took transformer from this UPS, connected it to AC Line in series with 100 watt lamp and got a shiny light :). > > Otherwise if it is a regular box type power supply, and sometimes even > server supplies, if you open the power supply cover there is a good > chance that you will find bulged capacitors - the number one failure of > power supplies everywhere. > > Although it is somewhat rare to have catastrophic over voltage /output/, > I've seen it happen with ugly blackened charred circuit results. > > Usually as capacitors slowly go bad, a supply simply becomes weaker. > > But a supply typically uses one of the output lines (say the +5V line) to tap > voltage feedback which self adjusts the regulation circuits. > > Sometimes the capacitors on that line go bad such that they cause too > much load on the line or else very weak filtering and high ripple voltage. > Then the regulation attempts to compensate by driving harder to put more > voltage on that line to make it increase to the correct voltage (say +5V). > But in doing so, the supply unwittingly /increases/ all the other supply's > output voltages beyond their rating, since all output voltages come from > the same output transformer. > With catastrophic results. I know only basic principles of Impulse power supplies and this intro was rather interesting, thanks :).
> > Next supply you buy, if you want to trust it, ask a qualified technician > (well, me for example), to check the brands of capacitors in there. > If they are crappy brands such as Ltec, OST etc. do not trust it. > Ask the tech to install only trusted Japanese brands. I took a new 450 watt FSP from my work, so there was no choice at this time, but I hope that it will serve for long time (at least for 2-3 years). > > My order of preference: > 1: Panasonic. The (my) absolute go-to number-one trusted brand, ever! > 2: Nichicon, United Chemicon etc. all very fine manufacturers. Opened this FSP. There are caps labeled 'CAPXON'. What can you say about this brand? P.S. offtopic. I like electronic circuits and have lots of questions. Tim, if you don't mind, can you answer one of them, it's very simple for you, I think: Some time ago I made a JLH 1969 class A amplifier and it sounds great. I tested it with siglent sdg 1020 signal generator and atten ads 1102 oscilloscope before connecting to my yamaha ns-333 speakers. Results were very good - noise floor was as little as 5 millivolts. When I lean my ear directly to speaker, I hear nothing (volume regulator of my amplifier is always at 100%, because I use volume knob on my sound card). The main drawback is that I had to make air cooling for the amp because radiators for output transistors are rather small (I took them from processor fans). But I like silence - all my computers reside in store room, so in my working room there are only monitors, hubs, keyboards and audio equipment. Here is my question. Is it worth to make a class-D amplifier? I have TDA8920CJ chip and it has near 90% efficiency (comparable to 25% of my current amp), so this means, that I need only one small radiator without any fans. But what about sound quality? Thanks :) > > ------------------------------------------------------------------------------ > _______________________________________________ > Lmuse-developer mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/lmuse-developer ------------------------------------------------------------------------------ _______________________________________________ Lmuse-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lmuse-developer
