Help identifying caps needed for recap

[digge]

First of all sorry if this is the wrong part of forum but didn't know quite where to put it, since its not exactly a psu for a computer or similar but rather the power end of a microcontroller.

So here is my dilemma, i have this circuit board for an oven that semi works when it wants to. I tracked it down to that when it doesnt work i dont get any voltage from the mosfet so i thought i replace the critical parts of voltage area meaning the 2 caps, rectifier and mosfet. I can clearly see the rectifier has been very warm.

Ive tracked down replacements for the rectifier and mosfet but since I'm not very good at electronic design I'm not sure what to replace the caps with, are they low esr caps or would just about any cap work?

The caps are Nitsuko brand, ill list everything on them that i could read from them and hope you can help me with it

Nitsuko
35V
1000uF (M)
CE04W
MR(E) 105degrees
N222

And here is some pics if that helps

[Toasty]

Re: Help identifying caps needed for recap

>>i dont get any voltage from the mosfet<<

What MOSFET? You are showing a voltage regulator there. 5v

The rectifier -looks- fine.

This is a linear power supply. A cap replacement type is not as critical. Actually, they are probably fine. I think your problem lies elsewhere.

[digge]

Re: Help identifying caps needed for recap

sorry i meant voltage regulator not mosfet, made a slip in my head while translating there and the rectifier might look good in the pic due to bad pic quality, but it has actually been so hot its partially desoldered and is not seated flat on the pcb anymore, and it also has a brownish tone to it.

think replacing the rectifier and regulator would be enough? reason i wanted to replace the caps as well was that i thought they might short the circuit since i get no voltage from the regulator sometimes. Usually if i power it up from being unpowered for a while it works for 5 mins an then dies, so seems that heat has something to do with it. if i cycle the power it might come on but stay on for shorter time.

[Toasty]

Re: Help identifying caps needed for recap

Does the regulator get hot also? I'm thinking more of an overload in whatever it is supplying than a failed component here. The rectifier gets hot because there is an overload on the regulator. The regulator is thermally protected and that is probably why the voltage output shuts off.

Rectifier is capable of 1.5A / 200v
Regulator is capable of 1A max of 10v input

A bench supply would be of use here to test the output and determine the load. You could also break the connection on the output and use your VOM/DMM on current setting to see what the load draw is.

Being a linear supply, a low ESR cap is not critical here. But the price difference being negligible for 2 caps, I'd likely go with Panasonic FM's.

Check downstream components for an overload or failure.

Toast

[stj]

Re: Help identifying caps needed for recap

tou need to look at all those yellow translucent caps.
if any have cracks replace them.
or they will burn-up soon.
(moisture gets into them)

[digge]

Re: Help identifying caps needed for recap

Swapped the rectifier, voltage regulator and the two electrolytics and now the board seems to work.

The yellow caps are not part of the voltage circuit to the microcontroller and stuff, they go to some relays on the side of the board (barely seen on left side of first pic), even though they have tiny cracks on them i think they will be fine for now since its only on the surface.

Not sure what of the things i replaced that was to blame, cant measure the caps since i couldn't find a meter that would measure as high as 1000uF, so i guess ill have to just be happy it works for now Thanks a lot for your thoughts on this.