A GW Instek, PSP-405, Lab bench power supply repaired

[Bernique]

got it, many thanks

here is my dump

[gabiz_ro]

I have one  but under ISO-TECH brand and IPS 2010 model but same thing.
Was dead and after repair was de-calibrated.
I abandoned at that moment because of other projects.
I remember I dumped firmware and saved somewhere.I found it some time ago and give it a try with my little skills in reversing firmware.
Ghidra got confused since for that mcu in 16 bit mode have missing some instruction that are available only on 20 or 32 bit, can't remember, I posted on github on issue, get some fixes but still no go since on 16 bit can't decompile, on 32 bit can decompile but wrong addresses.
Anyway I remember that was a check at startup for something on serial port that may trigger calibration mode and looks like interactive from strings on firmware.
Can't be sure but may be enter key pressed, need to search on work PC, if memory not fail me the check was for 0x0A that I think is Line Feed

I'll upload tomorrow firmware. Maybe someone with greater skill can do reverse engineering.
( if I don't forget)

edit
Just remembered that I uploaded on github
https://github.com/NationalSecurityAgency/ghidra/issues/5901#issuecomment-1777612940

[Bernique]

order for EEPROM, capacitors & opto-coupler placed this morning
Should be there on the 25th morning

[p.larner]

is it smps or a linear topolagy?

[Bernique]

EEPROM received

I was about to plug one empty EEPROM on the PCB just for curiosity... is it useless ('cause no data inside thus startup will not occur) or does it make sence to verify that a non corrupted EEPROM is solving my issue?

[wraper]

EEPROM received

I was about to plug one empty EEPROM on the PCB just for curiosity... is it useless ('cause no data inside thus startup will not occur) or does it make sence to verify that a non corrupted EEPROM is solving my issue?

IIRC it will recreate most of data within EEPROM and it won't reboot, however output voltage will be totally wrong.

[Bernique]

 
I've got 50 of those AT24C08C to play with (minimum order qty @RS-Components)... rain is announced for tomorrow and SOIP8 adaptor is somewhere between China & France so no chance to dump your non_corrupted.bin into an EEPROM shortly
I'll give a try if I can 

[Bernique]

Hello,

I gave a try last evening... load the sain .bin into a fresh eeprom, solder it and boot the bench supply.
Unfortunatly, I still have the same situation: no output at all.

I need to look at another area than eeprom and capcitors which have been changed already earlier.