| Electronics > Repair |
| Korad KA3005P power supply faulty/repair |
| << < (21/27) > >> |
| mos6502:
Hey, at least something :) Now you only have to program your own firmware and redesign the regulation circuitry. ;D |
| Kleinstein:
Having something like 330 µF at the output of a lab power supply is about normal. There are supplies with even more capacitance at the output, that are still considered good. A normal lab supply is not expected to be very fast in regulation, as this makes is really difficult to have it stable with any possible load. There is also not much sense in making the supply faster than 1 m of cables. So if you have a load that needs fast current spikes, add local decoupling capacitors. There are also PS designs that have way less capacitance at the output, but still have a poor / slow current limiting and may this way behave as if there would be an even larger capacitor. The funny high frequency transients look a little strange. So the question really is how much of this is at the output terminals and how much is just EMI coupled to the wires to the scope. |
| mos6502:
I disagree, 330µF is way too much. My TTI PL320 has 47µF and you can still kill a zener diode if you're not careful and dial down the voltage far enough. 330µF will fry a lot of stuff if there's a fault in your circuit. I'm not quite sure what you mean by "faster than 1m of cables". But a proper bench PSU will have separate sense connections to compensate for any lead resistance. So yes, fast regulation/low output capacitance are what makes a bench PSU useful. In the case of the Korad, you might as well buy a switching power supply like the CPS3205. It's smaller, lighter, cheaper and more efficient. |
| pomonabill221:
--- Quote from: uv3afl on January 09, 2017, 01:15:15 pm --- --- Quote from: tombi on January 09, 2017, 06:04:02 am ---Way back in the thread somebody posted reverse engineered schematics... --- End quote --- I have found some better schematics for the device. And as the support for the device is far from being called 'support', I think this must be here. Attaching to the message. Maybe someone will stick it up to some 'documents' theme. --- End quote --- Well my efforts were for not then? Thanks for posting the schematics! Finally after 4 years,, we have complete schematics! |
| uv3afl:
--- Quote from: pomonabill221 on January 10, 2017, 11:36:36 pm ---Well my efforts were for not then? --- End quote --- I shouldn't say so! If you look closer to the schematics you will notice some annoying mistakes. For e.g. at main board two 'GNDF' at upper of R13. Looks obviously confusing. :palm: And here I take your sheet and set everything into places ;) I'm too lazy to take CAD and draw everything like it shold be. By the way, good moment to say thanks for your rev-eng job! :-+ It was first internals info about this PS that I've seen! |
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