Hello all,
first post on this forum... where I landed after googling from France for
faulty PSP-405 I spent a couple of hours reading here and there, made some tests, but still requesting some support to have this power supply back to life. This is the main reason why I'm using this very helpfull post started long ago
Resume of the situation:
I received my Instek PSP-405 from a friend who pasted away recently, which is my main motivation to repair it
I tried to power it up: I had a normal screen on for a second, and then it turned blank (only backlight).
Based on my reading, I checked the best candidate capacitors (C49, C25, C29 & C33) and C29 was found totally scraped (33pF with a nice blown top!), while the others were within 10% of their original value (with ESR around 0,8Ω)
To stay on the safe side, I decided to change C25, C29 et C33 as I had some stock. I put C49 back in place (no spare).
After this, I now can recover the normal startup with the expected screen. I can select values (V, I, P)... all is fine
Almost fine
... 'Cause when pressing OUTPUT ON, tension is rising up and going back to quite zero
What's next?Before trying to dig into the EEPROM (some other readings
), I made a visual inspection of my power board... and found that IC2 (COSMO 1010) is quite dirty/over heated? (and connected to C29).
I also scope the output while OUTPUT is OFF... and go a nice signal from the main with 50Hz frequency
(and confirm that output is quite zero with the same signal whatever OUTPUT is ON or OFF!)
I tried to identify this IC2 on the schematics given in the various post but couldn't find my way... sorry for being so novice
My question:I suspect this IC2 to be part of my problem (I belive it is supposed to command high voltage and being faulty could lead to let the 50Hz going everywhere it should not!). Does anyone of you with better expertize then mine could confirm this diagnostic or give me another track to follow?
PS: I have attached a few pictures for reference below... but can provide some more detail if needed