Hello Folks, Since this is my first post on the EEVBLOG forum wanted to say Hi to ALL
I was a happy owner of Korad KA3005D-3S, until left half of my power supply failed. During testing of a system (12V 2A), cracking sound burning smell and smoke came out of vent holes.
Its only been used few times since I've bought it 13 months ago but distributor refused a warranty service (12 months warranty).
Since I’m electronics engineer I’ve turn it apart and fund that the microprocessor board has malfunction caused by fan short circuit (or possibly other way around). ULN2003A was blown, I’ve replaced the fan and ULN, to find out that 3 op amps are also shorted (TL082C), replaced those but that was not the end. There was something still short-circuiting 3.3V line, found out that it’s a microprocessor with sanded markings.
Can you help me in any way with fixing my PSU? I would need:
- a programmed microprocessor (probobly wont get it) or
- full microprocessor board (maybe Korad sells replacements?) or
- a firmware for the uC (second board from other half of my PSU is ok, but i doubt Korad didn't lock the firmware) or
- i could possibly write my own firmware, but reverse engineer the board would be a nightmare
Thanks in advance for any support.
PS. On the attached photo the board have desoldered 3.3 LDO and a ceramic cap on it, it was to check what is shorting out 3.3V line.