Rate PAN STAR PSA-230P ATX v1.2

[rattlesnake]

Hello everybody,

I picked up this PSU almost for free and I'm thinking it could be suitable for an old system (Pentium/K6-2/P-III). It's quite heavy, so that's always good.

What do you think about its components and overall quality?

[stj]

Re: Rate PAN STAR PSA-230P ATX v1.2

doesnt look to bad to me.

[momaka]

Re: Rate PAN STAR PSA-230P ATX v1.2

Concur with sjt.

PSU looks OK for what it is - an old 235 Watt PSU with heavy bias towards 5V-based systems with that 5V rail rating. Classic half-bridge with what appears to be 2-transistor 5VSB circuit. Main transformer is 35 mm, so that's good. Output toroid size and caps appear adequate. Heatsinks also appear adequate, along with the rectifiers on the secondary side (12 Amp rect. for the 12V rail and 25 or 30 Amp rectifiers for the 3.3V and 5V rails.) The 470 uF input caps should be perfectly adequate too, if they are still OK (they are dodgy brands... but these last a good amount of time when not used with an APFC circuit, which this PSU does not have.)

My main and only concern with this PSU would be the condition of the electrolytic caps on the output and the small ones on the primary side. Check and replace any and all that are getting above 15-20% of their rated capacity - that's usually a sign that the caps' leakage current is going up due to the electrolyte breaking down. The 5VSB does appear to have a small "critical" cap on its primary, so definitely make sure that one is either OK or gets replaced. Otherwise, you might get a run-away 5VSB with really high voltage that can easily kill an old motherboard.

Other than the conditions of the e-caps, the rest looks good to me. I wouldn't hesitate to use this in an old retro / classic PC. Don't use on a modern PC, though - that 12V rail's rating of 8 Amps is way too low for modern PCs and likely won't support even 2-3 Amps of current draw without a large load on the 5V rail first.

[rattlesnake]

Re: Rate PAN STAR PSA-230P ATX v1.2

Thank you for your replies!

My main and only concern with this PSU would be the condition of the electrolytic caps on the output and the small ones on the primary side. Check and replace any and all that are getting above 15-20% of their rated capacity - that's usually a sign that the caps' leakage current is going up due to the electrolyte breaking down.

I'll definitely check them and report back.
Aren't new caps sometimes rated, let's say 470uF, and when you measure them they're 500uF, or 550uF? I thought that there was a -/+ 15-20% tolerance. Even reading some datasheets I think I read they say that values are within a certain %.

The 5VSB does appear to have a small "critical" cap on its primary, so definitely make sure that one is either OK or gets replaced. Otherwise, you might get a run-away 5VSB with really high voltage that can easily kill an old motherboard.

Would you please tell me which one is the 5VSB primary capacitor? is it near the transformers?
And just for curiosity, what would get fried first?

[momaka]

Re: Rate PAN STAR PSA-230P ATX v1.2

Aren't new caps sometimes rated, let's say 470uF, and when you measure them they're 500uF, or 550uF? I thought that there was a -/+ 15-20% tolerance. Even reading some datasheets I think I read they say that values are within a certain %.

Yes, electrolytic caps are indeed usually rated at +/-20% for their stated capacity. But when it comes to old caps, I usually find that if the cap(s) read over 15% (and especially over 20%) of their rated capacity and ESR still looking perfect or suspiciously low, chances are they are starting to fail due to electrolyte breaking down. This is moreso the case with 2nd and 3rd tier caps. Japanese caps usually read normal or start to read below capacity (save for some old ultra-low ESR series, but that's a different matter.)

Would you please tell me which one is the 5VSB primary capacitor? is it near the transformers?

Small 5x11 mm cap above the small "EEL-16-2" transformer.
Probably going to be a 10, 22, or 47 uF @ 25V or 50V.
We often call it the "critical 5VSB cap" simply because some 5VSB designs will go very over-voltage if this cap goes high ESR.

There are also two small caps above the "ERL-35" amd "EE:-16-1" transformers. These will have matching values, typically 1, 2.2, 4.7, or 10 uF. These are for driving the BJTs on the primary. Also check if these are OK, though they are not critical like the cap above.

And just for curiosity, what would get fried first?

Whoever's the weakest link.
Depends a lot on the motherboard. If the mobo has any chips that are rated for 5V (meaning these are usually rated 4.75-5.25V working range and 5.5V max.) and tie directly to the 5VSB, then these will bite the dust first. Most newer mobos don't use 5VSB directly and instead rely on a 3.3V STB line that is generated by the 5VSB, so most components like the SuperIO / LPC, LAN, and flash chip will be behind the 3.3V regulator and get protected.
So again, hard to say who's gonna go first.

[stj]

Re: Rate PAN STAR PSA-230P ATX v1.2

check the fan and oil the shaft too

[rattlesnake]

It's been a while... finally I'm back to this project.

I removed all the electrolytic capacitors, here are all the measurements:

Near the diode bridge
JPCON 470µF 200v 340x220mm - 332.3µF 0.00Ω - Replace?
JPCON 470µF 200v 340x220mm - 355.4µF 0.00Ω - Replace?

Are these ok?

The one above the EEL-16-2 transformer:
JPCON 22µF 35v 11x5mm - 25.9µF .96Ω - Replace
This must be the 5VSB capacitor.
According to Momaka's recommendation, it's better to replace this one as it's 15% off.

The other two above EEL-16-1 and ERL-35
<BH> 10µF 50v 11x5mm - 10.95 1.1Ω
<BH> 10µF 50v 11x5mm - 11.05 1.1Ω
These seem to be ok.

Below the transformers
JPCON 47µF 35v 12x6mm - 47.2µF .8Ω
JPCON 220µF 16v 12x6mm - 253µF .21Ω - Replace
<BH> 10µF 50v 11x5mm - 11µF 1.3Ω

On the other side of the heat sink, near the coils
JPCON 47µF 35v 12x6mm - 46.6µF .61Ω
JPCON 220µF 16v 12x6mm - 237µF .34Ω

On the left side
<BH> 1µF 50v 11.5x5mm - 1.084µF 2.5Ω
Wincap 4.7µF 50v 7.3x4mm - 4.886µF 2.1Ω

Near the cables
JPCON 2200µF 16v 23.5x13mm - 2399µF .00Ω
JPCON 2200µF 10v 20x10mm - 2523µF .04Ω - Replace
JPCON 2200µF 10v 20x10mm - 2983µF .00Ω - Replace
JPCON 1000µF 10v 15x10mm - 1382µF .04Ω - Replace
JPCON 220µF 16v 12x6mm - 267µF .18Ω - Replace
JPCON 220µF 16v 12x6mm - 181µF .34Ω - Replace

As you can see most are outside Momaka's recommended 15% threshold.
I'll try to source replacements, but since I can't buy quality capacitors it will be hard.
The ones I'm more worried about are the big 470µF ones. They are 25-30% off. I wonder, is this normal for such big capacitors or I must replace them too?

[прямо]

If you are doing a recap, you might as well replace them all. Those caps that are measured ok for now, will be bad in the near future and then you will have to open up the PSU again.

[stj]

i would just do all of them
the 200v ones are suspicious - i wonder if they are re-sleeved 330uf caps?
there is alot of fraud like that in cheap psu's!