I got this Coolmax RM-850B. 850W? Yeah, right. I think it's more like 400W or so. But anyway I got it assuming it was dead, mainly for parts. But for grins I decided to open it to sneak a peek at what exactly failed.
So the normal PSU debugging: Plug in and try it!:
+5VSB: DEAD
Okay. So I'm dead in the water here and have to open it up to take a peek.
So I see a UCC3818AN APFC controller and TNY268P 5VSB switcher. Strange, TNY268Ps should be fairly reliable.
Okay. Need to see where I can tap off the board. So I pulled the board and see this:
Wow... Reconnect maybe? Okay, now the bottom:
Holy crap, now what happened to the insulation?
Thank goodness for three wire grounding and thank goodness for FR-boards.
Now... is this fixable?
Actually I think this is worth a shot jury rigging a fix...
BTW: Yes, the FR4 track protected the input fuse... (Fuse is still intact). Will need to see if the input circuitry is still good or not, like the bridge - then again there are two bridge rectifiers in parallel so that's pretty beefy...
And dim bulb will definitely be employed trying to repair this thing...
So the normal PSU debugging: Plug in and try it!:
+5VSB: DEAD
Okay. So I'm dead in the water here and have to open it up to take a peek.
So I see a UCC3818AN APFC controller and TNY268P 5VSB switcher. Strange, TNY268Ps should be fairly reliable.
Okay. Need to see where I can tap off the board. So I pulled the board and see this:
Wow... Reconnect maybe? Okay, now the bottom:
Holy crap, now what happened to the insulation?
Thank goodness for three wire grounding and thank goodness for FR-boards.
Now... is this fixable?
Actually I think this is worth a shot jury rigging a fix...
BTW: Yes, the FR4 track protected the input fuse... (Fuse is still intact). Will need to see if the input circuitry is still good or not, like the bridge - then again there are two bridge rectifiers in parallel so that's pretty beefy...
And dim bulb will definitely be employed trying to repair this thing...
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