the gutless, bloated, and fried power supply hall of shame

[Pentium4]

Got some more to share. First up is a Solytech unit that just had some Teapo's die. Going to replace them soon. Some look like they are hard to get to. After a recap this thing is going to be a pretty solid power supply. Manufactured December, 2005. Tell me what you guys think of it.

[IMG]http://img443.**************/img443/6458/dsc07973.jpg[/IMG]

[IMG]http://img13.**************/img13/3310/dsc07974l.jpg[/IMG]

[IMG]http://img804.**************/img804/4708/dsc07975s.jpg[/IMG]
Can't tell if some of the joints are heat damaged, does it look like it?
[IMG]http://img152.**************/img152/8717/dsc07979d.jpg[/IMG]



Up next is this piece of garbage from an unknown brand, try not to laugh too hard at the brand name....It claims to be a 400W PSU. Maybe it wouldn't be so bad after replacing the Jpcon and Fuhjyyu caps, but those transformers look pretty wimpy, as well as the 4 diode treatment and next to nothing for transient filtering...

[IMG]http://img837.**************/img837/1394/dsc07980y.jpg[/IMG]

[IMG]http://img189.**************/img189/7558/dsc07976sm.jpg[/IMG]

[IMG]http://img849.**************/img849/1416/dsc07977x.jpg[/IMG]

[IMG]http://img99.**************/img99/8643/dsc07978c.jpg[/IMG]

Is this junk worth doing anything to, salvaging anything off it, or is it a tosser?

[ben7]

LOOOOOL!!!

'icute'


and I see the cheapo-teapos are bulging again!

[c_hegge]

Ohhh, now isn't that cute?

[momaka]

Hmmm... Dajavu or what? This is the same exact PSU as the ones that Mockingbird posted.

Originally Posted by Th3_uN1Qu3

Do yourself a favor and junk them already. I have at least one unit from almost all low-end ATX platforms lying around, and the one you have is the worst.

I disagree.

While these PSUs are very wimpy in terms of guts, they can actually be quite decent if you put good parts in them since they are based on CWT's ISO line. And unlike other cheap PSUs, the soldering in these is actually good. See this thread:
http://www.badcaps.net/forum/showthr...hlight=CWT+ISO

Again, the Cyberlink I had was powering a 64W TDP Pentium 4 which peaks at ~80W max under full load. The Cyberlink is only able to provide 75W on the 5V rail, yet the PC seems to have worked for at least a year. The ECS motherboard from that PC is still fine - I'm using it as my gaming computer .

Originally Posted by mockingbird

Am I right in assuming I'm looking at the three TO-220 packages on the secondary side? Here are the markings:
1) STPR1020CT
2) STPS1545CT
3) STPS1545CT

Looking at the datasheet for the STPS1545, it's a 15A part... The datasheet for the STPR1020CT says "2 x 5A", is this my 12V rectifier!?.

Yes.
So it terms of "raw" DC current, your PSU is good for 10A max on the 12V rail, or 120 W.

Originally Posted by mockingbird

Tracing back the 12V circuit, yes, I see that I've got that same Fuhjyyu TM 16V 680uF cap which obviously is filtering it alone because the coil is missing for the pi filter...

Ok, ok, you're starting to convince me... Let me ask you this... Let's say I switched the 16V 680uF cap with some nice, highly rated 10mm cap with a higher capacitance (Or should I stick to the same capacitance), would this help me any?

If you want to have a fairly clean, stable power output it's good to have at least 2x 2200uF caps on the 3.3V rail, 2x 2200uF caps on the 5V rail, and either 2x 1000uF or 1x 2200uF cap on the 12V rail, 1x 1000uF on the -12V rail, 1x 470uF on the -5V rail, and 2x 680uF on the 5VSB - all with PI inductors between each set of caps (-5V and -12V rail excluded).

With that, you should be able to run your Semprons fine, although the PSUs may run a bit warm.

All in all, though, I would say just use them for parts. And reason I say that is because the primary side of these PSUs is not that great either (it's missing all of the input filtering and the bulk caps are tiny).
These PSUs do work great for powering small electronic projects, though.

[c_hegge]

If there is no input filtering, I just junk it on sight. Re-building them is more trouble than it's worth IMO.

[everell]

Power supplies without input filtering tend to have more bulging capacitors on the output side than power supplies with input filtering. I wonder why???? There IS a direct correlation.

Conclusion: Power supplies with good input filtering give superior long term performance.

[Agent24]

I would say that power supplies without input filtering are also more likely to have crappier capacitors, and also more likely that the capacitors would be under-rated for the application.

[PeteS in CA]

A company that would cheap out by omitting the AC I/P filter is also likely to have used crappy quality caps and used parts whose ratings are barely adequate (hypothetically adequate, of course).

[kaboom]

ICute ,=ICrush

[shovenose]

I was going to post a Logisys here but we needed a PSU for our phone server...

[momaka]

Originally Posted by c_hegge

If there is no input filtering, I just junk it on sight. Re-building them is more trouble than it's worth IMO.

You should pull the schottky diodes at least. Many OEM PSUs from HiPro, Bestec, and LiteOn have extra spots for more schottky diodes. Adding them in improves the efficiency and makes the PSU able to handle more current on that rail. I'm doing that right now on a Bestec ATX-250-12Z.

[everell]

Originally Posted by momaka

You should pull the schottky diodes at least. Many OEM PSUs from HiPro, Bestec, and LiteOn have extra spots for more schottky diodes. Adding them in improves the efficiency and makes the PSU able to handle more current on that rail. I'm doing that right now on a Bestec ATX-250-12Z.

Bestec?

Folks talk about Bestec being so bad......throw away on site........maybe worse than Powmax!

[c_hegge]

Originally Posted by momaka

You should pull the schottky diodes at least. Many OEM PSUs from HiPro, Bestec, and LiteOn have extra spots for more schottky diodes. Adding them in improves the efficiency and makes the PSU able to handle more current on that rail. I'm doing that right now on a Bestec ATX-250-12Z.

The real cheapies don't usually have any schottky diodes. More often than not, they are just low capacity fast recovery rectifiers, which aren't worth scavenging.

[momaka]

Originally Posted by everell

Bestec?

Folks talk about Bestec being so bad......throw away on site........maybe worse than Powmax!

Bestec is fine by me.
Although, if given a choice of OEMs, I would pick HiPro, Delta, or LiteOn (in that order).

Originally Posted by c_hegge

The real cheapies don't usually have any schottky diodes. More often than not, they are just low capacity fast recovery rectifiers, which aren't worth scavenging.

On the 12V rail yes. But on the 5V and 3.3V rail, they are *always* schottky diodes (at least I haven't seen one that doesn't so far). Most of the time, the 5V and 3.3V rails have 15A or 20A schottkys (sometimes 30A if you are very lucky).

Many OEMs are single-transistor forward-converter PSUs, so you can use those low voltage schottky diodes from the 5V and 3.3V rails of the cheap PSUs on the 12V rail of the OEMs without problem.

The 250W Bestec I have has a single 20A, 45V schottky on the 12V rail and an empty spot for another one. I'll be adding a second 20A schottky in there. This will boost the raw capacity to around ~25A. Not that the power supply can do that much, but I will be using it with a 105 W TDP CPU, so boosting the efficiency will matter in this case.

By the way, I got that 20A schottky from a cheap Meico/Q-Tec PSU. In case you are wondering, it's one of these:
http://www.badcaps.net/forum/showthr...ighlight=m-tec
I've used parts from that PSU to fix many other PSUs.

[mockingbird]

Folks talk about Bestec being so bad......throw away on site........maybe worse than Powmax!

This doesn't make any sense coming from you.

You're re-capped many Bestec PSUs and I have a few here I was even going to ask you about when I got around to re-capping them (Relocating the cap near the diode that gets really hot, my Bestec is a slightly different revision than the one you posted this mod with).

[c_hegge]

Originally Posted by momaka

Most of the time, the 5V and 3.3V rails have 15A or 20A schottkys (sometimes 30A if you are very lucky)...

I don't scavenge anything below 30A. The other problem is that the rail which usually needs the extra capacity is the 12V, and you can't often use the 40v VRRM rectifiers (which most cheapies have on the 5v and 3.3v rails) on 12V Rails.

[momaka]

Originally Posted by c_hegge

I don't scavenge anything below 30A. The other problem is that the rail which usually needs the extra capacity is the 12V, and you can't often use the 40v VRRM rectifiers (which most cheapies have on the 5v and 3.3v rails) on 12V Rails.

Again, you're only half-correct.
For half-bridge topologies, you are right.
For single-transistor forward-converts, the reverse blocking voltage of the rectifier can be quite low - just only a bit higher than the rectified DC voltage.

Originally Posted by mockingbird

This doesn't make any sense coming from you.

He was joking

[everell]

Originally Posted by momaka

He was joking

Momaka is right, I was only joking. I have fixed and modified several Bestecs, and I think they are just as good as HiPro. I am running a Bestec ATX-400 on this computer because a recapped Antec Smart Power 450 watter kept giving problems.

As opinions go................I think that only morons trash or gut a Bestec while trying to modify and improve a Deer/L&C/Solytec or Powmax power supply!

The biggest problem with the mobo killer Bestec ATX-250 12E was a flawed 5vsb circuit. The problem was KNOWN long before I made the DM311 mod and showed that it is then a useful reliable power supply. Too many were bad mouthing Bestec instead of working the problem. For quite a while I took a lot of heat because I said the Bestec 12E was a good psu after my fix.

[momaka]

Originally Posted by everell

I have fixed and modified several Bestecs, and I think they are just as good as HiPro.

Perhaps the current Bestecs are, but the older ones (250W and 300W) aren't IMO. HiPro have always used massive heat sinks and very over-specced rectifiers. Bestec - not so much. Usually just enough to cover what's on the label, but not much more than that.

I just finished recapping that Bestec ATX-250-12Z today. Don't get me wrong, overall it's a good PSU, but it still has some minor issues/quirks that make me feel uneasy about it.

#1 - it cross-loads very easily.

I just tested it in a old Duron 750 MHz PC (which pulls power from the 5V rail). It's a 35W TDP CPU. Despite that, the 12V rail was quite high: 12.56V (just 0.04V shy of out-of-spec). The 5V rail was only mildly high: 5.10 V. <---- This shouldn't happen. Instead the 5V rail should dip below 5V in order to keep the 12V rail from getting close to being out-of-spec.

I then tested the Bestec on a 12V-based system (socket 939 Sempron 64 3400+). That one, the CPU is 59 W TDP, IIRC. 12V rail was still a bit high at 12.22 V while the 5V rail was also high (5.15V). <--- again, this should NOT happen.

Now compare that to my 250W HiPro, which regardless of whether I try it in a 5V PC or 12V PC, both rails are always close to their true value. FYI, both that Bestec and the HiPro are group-regulated PSUs so there's no excuse for Bestec's performance.

This is not unique just for my ATX-250-12Z either - it happens on my Bestec ATX-1956D as well (except for that one, the 12V rail is too low).

All in all, though, I do trust that Bestec, so likely after some more testing, I will be using it in one of my computers.

#2 - the active load circuit on the -12V rail

I simply dislike it. It can easily overheat and get out of control. I really don't understand why Bestec put such a complex (for its task) circuit in there instead of just increasing the voltage magnitude of the -12v rail and using a linear reg like the HiPro does.

[mockingbird]

Originally Posted by everell

Momaka is right, I was only joking. I have fixed and modified several Bestecs, and I think they are just as good as HiPro. I am running a Bestec ATX-400 on this computer because a recapped Antec Smart Power 450 watter kept giving problems.

Really? I'm still using the SP-450 I re-capped in this thread.... What sort of problems were you having with it? I noticed you tried to mod the 5vsb with this one and you had to use a different IC for the mod.

As opinions go................I think that only morons trash or gut a Bestec while trying to modify and improve a Deer/L&C/Solytec or Powmax power supply!

I have several of them here waiting to be re-capped as soon as I get around to it.

The biggest problem with the mobo killer Bestec ATX-250 12E was a flawed 5vsb circuit.

Do you think you could do your fix on a Fortron one of these days and document and photograph it for the amateurs?