Hey guys,
Sorry this one has stumped me... I've recapped lots of these PSUs for people recently without any issues, fairly basic nothing too tricky involved. I tested before the recap and all was fine, after the recap the fuse keeps going.
The only thing other than recap the PSU is I pulled the IC2 MOSFET up a little by melting its legs and pulling it though a little. I do this on all my recaps of this PSU because by default that MOSFET is too bent over which heats up capacitor C19 which I don't like.
I've tested everything I soldered with a multimeter, no shorts from what I can see. Any ideas welcome.
Phihong PSM-5341 blows fuse after recap?
Re: Phihong PSM-5341 blows fuse after recap?
A close up of IC2 and C19:
Re: Phihong PSM-5341 blows fuse after recap?
Fuse blowing tends to be mains side issues. The low voltage side has basic trip out on faults...
I would check the main switching transistor isn't shorted first of all. Also check for shorts around the small ic.
I would check the main switching transistor isn't shorted first of all. Also check for shorts around the small ic.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: Phihong PSM-5341 blows fuse after recap?
Looking at https://www.exxosforum.co.uk/atari/last/ ... 5341rc.jpg the big red mains voltage capacitor has its negative terminal (white stripe) on the other side. Thus, I assume @Steve got the polarity wrong (and is lucky that it didn't end in "fireworks"). The capacitor might have been damaged in the process and should be replaced once again.
PS: Not that it is relevant here, but IC2 is not a "MOSFET" (as mentioned in the initial post) but the -5 V regulator.
PS: Not that it is relevant here, but IC2 is not a "MOSFET" (as mentioned in the initial post) but the -5 V regulator.
Re: Phihong PSM-5341 blows fuse after recap?
@czietz Thanks ! I can't believe I did that! Must have been too tired, but yeah, this is why the forum is so helpful for a second pair of eyes!!! Cheers. Hopefully the cap is ok I'll run it through my tester to make sure, the fuse blows instantaneously so it was probably protected.
Re: Phihong PSM-5341 blows fuse after recap?
Great spot. Remote PSU debugging. Love it.czietz wrote: ↑Fri Jul 09, 2021 2:03 pm Looking at https://www.exxosforum.co.uk/atari/last/ ... 5341rc.jpg the big red mains voltage capacitor has its negative terminal (white stripe) on the other side.
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DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark