First post, by Datadrainer
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Hi there.
The PSU of a Pentium III PC pop after turning it on. The PSU was made in 2003. As soon as I heard the noise I cut off the current. Then I opened and dismounted it to check the inside.
What I have discovered, on the high voltage side:
- a crackled thermistor
- an odd looking filtering capacitor
On the low voltage side :
- some bulged caps
I think the noise came from the thermistor (cf. its crack). No smoke, just a little smell for a few minute. I tested it and seems fine (from the datasheet pov). Then I tested the PSU with a voltage monitor and the PSU is working fine with all voltage OK.
So as nothing goes bad except some aging electronic components. I think this PSU must have a refresh. And for that I would like to use some good quality ones.
The caps are 3300 µF 10V (x4) and 2200 µF 16 (x2) branded Fuhjyyu. Only some are bulged, but I'll replace them all by Panasonic equivalent (EEUFC1A332 & EEUFK1C222L).
The thermistor is a Microtherm SCK-2R512 [https://cdn.datasheetspdf.com/pdf-down/S/C/K/ … _Microtherm.pdf]. They do not exist anymore thermistors with the same characteristics. But I found an EPCOS/TDK B57364S0259M000 [https://docs.rs-online.com/1913/0900766b813c0c7c.pdf] could be suitable. This is an important component that protect the PSU from power peak and must be chosen wisely.
The AC filtering cap does not inspire me at all as not all common information we find on such component is written on it and it look low-end. The brand is UTX, model HQX. It is a polyester film capacitors, class X2 , 0.33 µF, 275 V AC. I would like to replace it with an EPCOS/TDK B32933A3334K000 [https://docs.rs-online.com/8f49/A700000008614371.pdf].
What do you think of my selections? Do you know more suitable ones?
Thank you 😀
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