To change, or not to change small caps in Fortrons?

[Behemot]

I have this great dilemma. Changing them requires desoldering those small milion-pin daughterboards usually, thats lot of work and many things can go wrong. But as they are not trustworthy brands, it may save me troubles in future. I have every possible replacement I could need, GP caps from 0,1 to 47 uF, low-ESR from 2,2 to 220 uF.

So guys, whaddaya suggest?? Change or not?

[Pentium4]

Re: To change, or not to change small caps in Fortrons?

Every time I recap one I see those and I really want to but don't want to risk it...I know what you mean but I usually leave them if they're Ltec and Teapo

[shovenose]

Re: To change, or not to change small caps in Fortrons?

I never change a cap unless necessary, and most of my stuff still works fine.

[Behemot]

Re: To change, or not to change small caps in Fortrons?

So you think I should leave them alone? True is, only time I have seen them go bad was when fan seized, but than simply everything (besides primaries - I hope! never measured them) was bloated.

But that are some great news! I can recap like two a day instead of moviing it just further and further every day without doing anything

[shovenose]

Re: To change, or not to change small caps in Fortrons?

Yeah just leave em unless you have horrible squealing noise.

[Behemot]

Re: To change, or not to change small caps in Fortrons?

Man it's one of those build-like-tank 500W units, that will take some time to crack it open and clean, oh dear, there is lot of stuff inside…

You won't believe, but it has actually blue molex connectors. I am almost sure this is OEM design for the original Blue Storm. Label says FX500-A.

[eccerr0r]

Re: To change, or not to change small caps in Fortrons?

I'd replace the 'critical' cap if you can identify it. This is the pwm IC's power filter cap that tends to be around 47uF. There's also one for 5VSB too...

[Behemot]

Re: To change, or not to change small caps in Fortrons?

Everything on the big daughterboard is far away from any heat-source. Found one 47 uF/16 V in there, but I would have to remove it and clean from ton of silicone to replace it.

As for +5 V SB, I/O is on small daughterboard, but all the bigger, stressed caps are on main board, accessible thus I will change them automatically.

[mockingbird]

Re: To change, or not to change small caps in Fortrons?

I've re-capped quite a few FSPs, have never re-capped the PWM controller or fully re-capped the fan controller board. They're all small Teapo caps. Coincidentally, I decided to start doing it for the next one, but I don't enjoy the prospect of unsoldering/soldering in tiny leads next to the 0402 components.

It's probably unecessary, but it would give me more peace of mind. If you're refering to small caps on the actual PSU PCB, yes, you should absolutely re-cap small startup caps and such.

[eccerr0r]

Re: To change, or not to change small caps in Fortrons?

Rule of thumb for UC3842/3844 PSUS (does not apply to OP, but just in case...) Always replace the one critical "startup" cap (PWM controller cap) when doing a cap job... I've seen this fail on all sorts of dead PSUs, granted if the psu is still working then likely this cap is still working too. I think the best way to locate this is to find a ~56K ohm to 100K ohm 2W resistor and track a small electrolytic capacitor going one way (the other way will lead to the big main capacitors... start from the other lead! note that I've seen this resistor implemented lots of differenet ways however, one PSU I saw three 27K resistors in series...)

For TL494+clones and other secondary side PWMs I don't think it's as much of an issue...

But yeah the fan controller board can be ignored for the most part...

[Behemot]

Re: To change, or not to change small caps in Fortrons?

Well there is some 47 uF/50V arround +5 V SB, but anyway, in FSP designs mostly the two +5 V SB filtering caps get cooked and bulge. Than the rail goes to hell and finally it refuses to start at all.

[Pentium4]

Re: To change, or not to change small caps in Fortrons?

Recapped one of these in a Hipro last week, working well and I feel a little better about the longevity

[Behemot]

Re: To change, or not to change small caps in Fortrons?

There is room you can dance in there You won't find it in Fortron

[Pentium4]

Re: To change, or not to change small caps in Fortrons?

Very true