Should I recap this unit?? FSP 350w

[jackywhatever]

I would like to recap this power supply as I use this on a computer for music reproduction.

How would you rate this PS at the first place?

Should I change some or all of these caps?
OST 200v 470u x2
OST 16v 3300u
Teapo 10v 2200u x5
Teapo 10v 1000u
some more but all under 100u, mostly teapo as well

By the way all of these caps are not very good... surprisingly though the PS runs very cool, um

[Per Hansson]

Re: Should I recap this unit?? FSP 350w

Teapo and OST are usually fine for powersupply duty so long as the fan spins somewhat decently (so it does not get too warm in there)

Unless you have identified caps as starting to fail I would just leave it alone
It looks like a decent PSU to me

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

Teapo and OST are usually fine for powersupply duty so long as the fan spins somewhat decently (so it does not get too warm in there)

Unless you have identified caps as starting to fail I would just leave it alone
It looks like a decent PSU to me

Thank you for your input.

Will changing caps end up giving
1. more stable voltage (minimizing spikes) or
2. make the PS run at lower temperature?

[Per Hansson]

Re: Should I recap this unit?? FSP 350w

If the capacitors have started to fail then yes it will improve the stability and reduce the operating temperature

However if they are fine there will be no difference
(Might even get worse depending on how well matched the new caps are to the PSU's Pi Filters etc)

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

If the capacitors have started to fail then yes it will improve the stability and reduce the operating temperature

However if they are fine there will be no difference
(Might even get worse depending on how well matched the new caps are to the PSU's Pi Filters etc)

thank you, it sounds like I can live with it for many more years, which is great

I even tried to touch the small-ish heatsink inside the PS after having the computer on for a day. Still cool and safe to touch

[Per Hansson]

Re: Should I recap this unit?? FSP 350w

I even tried to touch the small-ish heatsink inside the PS after having the computer on for a day. Still cool and safe to touch

Ok, with the power off I presume
Be aware that in most powersupplies the primary heatsink (the one you did not touch per your explanation) is live at AC voltage!
(Yea, before you ask I found out the hard way...)

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

Ok, with the power off I presume
Be aware that in most powersupplies the primary heatsink (the one you did not touch per your explanation) is live at AC voltage!
(Yea, before you ask I found out the hard way...)

argh... thanks for reminding
just wondering, per my limited knowledge on caps, those caps used to smooth output current are mostly over 1000uf. what do the smaller caps do (those under 100uf)? for control circuits?

[mockingbird]

Re: Should I recap this unit?? FSP 350w

Is that an FSP 350-60THN or a 350-PN/B?

[etnietering]

Re: Should I recap this unit?? FSP 350w

argh... thanks for reminding
just wondering, per my limited knowledge on caps, those caps used to smooth output current are mostly over 1000uf. what do the smaller caps do (those under 100uf)? for control circuits?

You are correct. The large caps are for filtering the output voltages, and the small ones are for control/timing/whatever. Most of the time...in this power supply I had a 47uF cap in parallel with a 2200uF cap on the 12v line.
If/when you end up recapping this, you should replace the small caps too. If they go bad the voltages can go way way out of spec and toast motherboards and hard drives and everything else.

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

Is that an FSP 350-60THN or a 350-PN/B?

it says only ATX350F on its case, it's a fairly aged unit

You are correct. The large caps are for filtering the output voltages, and the small ones are for control/timing/whatever. Most of the time...in this power supply I had a 47uF cap in parallel with a 2200uF cap on the 12v line.
If/when you end up recapping this, you should replace the small caps too. If they go bad the voltages can go way way out of spec and toast motherboards and hard drives and everything else.

thank you for your input.

I have two other PS units that runs quite hot and over-voltage (e.g 12V at 12.3V)
Should I replace all of these caps to new same value caps or I should go for larger uf?
200v 820u x2
16v 2200
16v 470 x2
10v 2200 x3
6.3 4700 x2
all Su'sscon (spelling maybe off)

In a PS, should I go for longer life caps or lower ESR caps?
2000 hrs enough for a PS?
is 105C a minimum?

[Per Hansson]

Re: Should I recap this unit?? FSP 350w

All decent caps are rated for 105°C
For PSU usage it would be preferable to aim for longer life vs lower ripple
That being said many (including me) use caps that are "intended" for CPU VRM usage in powersupplies and it works fine too...

But as I said before it is important to stay atleast reasonably close to the original caps spec, since that is what the whole Pi Filter is tuned for (otherwise you could end up with more ripple when using a capacitor that in reality has much better ESR rating for example)

Su'sscon (spelling) are known crap, I would replace those
The large input filtering cap(s) can generally be left alone, because they don't operate under as harsh conditions as the secondary side, so they are generally fine (Unless you do use them in a place with very poor incoming line voltage of course)

[stj]

Re: Should I recap this unit?? FSP 350w

panasonic's new FK series look good!

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

The large input filtering cap(s) can generally be left alone, because they don't operate under as harsh conditions as the secondary side, so they are generally fine (Unless you do use them in a place with very poor incoming line voltage of course)

Do you mean the 200v+ ones?

[Per Hansson]

Re: Should I recap this unit?? FSP 350w

Do you mean the 200v+ ones?

Yes

[Scenic]

Re: Should I recap this unit?? FSP 350w

panasonic's new FK series look good!

those are new? o_O
http://cgi.ebay.com/290416806311

[stj]

Re: Should I recap this unit?? FSP 350w

i would never buy caps off ebay!

specaially those japanese caps that the site says are made in malasia and ship from HK!

[Behemot]

Re: Should I recap this unit?? FSP 350w

it says only ATX350F on its case, it's a fairly aged unit

I've seen several unit of this age, most of them were almost identicall no matter how they was labeled. But interesting are these small heatsinks in your piece.

I'm maybe little bit paranoid, but I recap everything I can just for the feeling everything is and will be allright much much longer than with these crap caps. Also overclocking is better with recaped PSU

[Scenic]

Re: Should I recap this unit?? FSP 350w

i would never buy caps off ebay!

specaially those japanese caps that the site says are made in malasia and ship from HK!

that store i linked to above is one of the very few that only sells genuine caps. he's aware of the fakes.. talked to him a lot via ebay PM's..

[jackywhatever]

Re: Should I recap this unit?? FSP 350w

is it a nice idea to increase capacitance on the output side of the PS? google did not give me a definite answer.

my understanding so far is,

1. increasing capacitance will help with ripple, but decreasing the speed of a cycle. does that matter at all in a PS?

2. increaseing capacitance may induce more instantaneous load to the PS. due to higher surge at startup. Is that true and how bad it is?

2. let's say a PS is fine on ripple, but constantly giving lower/higher than desired voltages. Can this be solved by the mean of recap? What's the strategy?

[370forlife]

Re: Should I recap this unit?? FSP 350w

I frequently increase the capacitance on any psu's I repair. Capacitance may not help much with ripple, that has to do more with ESR and the PI filters. On a ps you don't want to stray too far from the ESR of the original caps as the pi filters are "tuned" in a way to the ESR of the caps and increasing or decreasing the ESR can increase ripple. More capacitance can help with transient response and may help voltage regulation, that also can be helped by using higher capacity schottky diodes.