Electronics > Repair
Korad KA3005P power supply faulty/repair
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tombi:
Sorry,

Way back in the thread somebody posted reverse engineered schematics and D1/D2 were between the voltage control and current control opamp and the pass transistors.

I was thinking like 1nF - nothing major.

Tom
mos6502:

--- Quote from: tombi on January 09, 2017, 06:04:02 am ---Way back in the thread somebody posted reverse engineered schematics and D1/D2 were between the voltage control and current control opamp and the pass transistors.

--- End quote ---

That would slow down the regulation even more. The reason a designer would put a ridiculous amount of capacitance like 330uF on the output of a linear power supply is because he's trying to make up for the slow regulation. Sorry guys, but everything points towards the fact that this PSU is garbage. I wouldn't consider it using for any electronics work because of the 330uF at the output alone. Maybe it's OK for charging car batteries.  :-DD
uv3afl:

--- 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.
uv3afl:
Now couple more pics about 'garbage' )) One of them:

 - garbage on output terminals when the load is soft-off and you hard-powered off the PS. The second one:

- garbage on output terminals when you momentarily press/depress power-on hardware button. How about killing something attached to PS with that? Hopefully too short, but... Anyway, do know.
uv3afl:
Some more news!
My dispute with the seller at Aliexpress has just finished successfully. They agreed that the 'feature' of not displaying output voltage when delta between Set and Out voltages is less than 0,2volts is a constructive defect and will refund me half-price of the PS.
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