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Old 03-05-2021, 08:11 PM   #17
Join Date: Aug 2014
City & State: Delaware
My Country: USA
Line Voltage: 120VAC
I'm a: Hobbyist Tech
Posts: 119
Default Re: 1300W PSU - Help with replacement mosfet

Originally Posted by momaka View Post
Check the primary input electrolytic caps too. Usually blown APFC components is a result of the primary caps going either short-circuit or open-circuit / low capacitance. Not uncommon for these to go bad either. You will need an ESR + capacitance meter to test them, though (i.e. can't do it with just a regular multimeter.) The cheap GM328 component testers online will do this... or just spend the $8-12 on new input (and quality Japanese 105C too) caps, whichever you prefer. If buying new, make sure the caps are rated for at least 420V... or better yet 450V. APFC does not last long with 400V caps from what I've been seeing so far.
I do have both an ESR meter and a capacitance meter.
the two big caps ( i think these are what youre referring two)
are rated 470uf 400V CapXon
1st: 427uf .167 ESR
2nd: 422uf .177 ESR

both measure OL in resistence mode
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