Bestec ATX-250-12Z rev D

[ptbo_bob]

Hey, everybody! I'm so new that some forum functions still won't work, that should go in the near future, and I'd bet that this PSU has been a regular topic. I have a simple problem; I have most of the caps ripped out of this PSU, and would like to find a board layout diagram and schematic for it. I have a Jamecon 16v 1000uf that tested OK but will still get replaced, and needs to go back in amongst a bunch of what were *really bad* Jamecon 10v 2200uFs that hopefully will go back in as Nichicon 16v 2200uFs - I have it on pretty good authority that anything less than 16v caps suck, and I doubt the price would be much different for the (perceived?) improvement in reliability. (Confirm or deny, anybody? Opinions, please, no fans or flames! <^8#)

Looking into the open PSU, with the wiring loom to the top right, there are basically two rows of caps running down from top right, mixed in with the wiring nightmare! <^8# If someone could confirm that the 1000uF goes into the second from the top, second row in (next to the choke), I'd appreciate it (it's where I was going to put it anyway, but also considered just replacing ALL of them with 16v 2200uFs, problem solved! <^8#)

I took out 4 bulged 2200uFs then took the other two out anyway, they're all the same caps, 4 bad mean two yet to come, and having just bought an LCR/ESR meter, I tested them all.

All were bad, two undetectably by visual inspection. THAT's what I bought the ESR meter for!! Touchdown!! But the bigger answer was, Yes, Virginia, caps can go bad and not look ANY different from new caps!! Which sucks, of course...

And I have had my newbie hobbyist EEheart broken - the ESR meter is not what I hoped it would be for testing in-circuit...!! <^8# I got enough skewed readings from this one PSU to make it clear that, if I want to be able to trust the meter, I'm going to have to isolate at least one lead...

Yep, you really DO learn something new EVERY day! <^8#

[momaka]

Re: Bestec ATX-250-12Z rev D

I have a simple problem; I have most of the caps ripped out of this PSU, and would like to find a board layout diagram and schematic for it.

I can get that for you tomorrow. I have an ATX-250-12Z rev D2R, so should be nearly the same thing.

I have it on pretty good authority that anything less than 16v caps suck, and I doubt the price would be much different for the (perceived?) improvement in reliability. (Confirm or deny, anybody? Opinions, please, no fans or flames!

Not exactly.

There are good quality 6.3V and 10V caps, just as there are 16V caps.
Yes, there actually *will* be a small price difference between the 16V caps and 6.3/10V caps. But that's not as much relevant as is the fact that the 16V caps will be physically bigger, so you might not be able to fit them in if you get all 16V caps.

Typically, I use 6.3V or 10V caps for the 3.3V, 5V, and 5VSB rails (and -5V rail, if there is one). Only the 12V (and -12V) get 16V caps.

If I remember correctly, I was able to squeeze in a 12.5 mm diameter Panasonic FC cap on the 12V rail in place of the old 16V 2200 uF CapXon cap with 10 mm diameter.

Anyways, here is a list of caps I use for power supplies:
https://www.badcaps.net/forum/showpo...22&postcount=9

[ptbo_bob]

Re: Bestec ATX-250-12Z rev D

Actually, I thought I had it narrowed it down to either of the two closest to the extreme upper right (output wiring loom top right.) There are actually 3 sort-of rows of caps between the edge of the board and the chokes, plus another between the two chokes (for a fourth row, as it were). The one between the two chokes is out, the first (from the top) in the third row is a 16v 2200uF cap, the third is a 16v 1000uF cap, and I suspect the errant 16v 1000uF cap I removed that tested OK belongs between them. Everything else I removed from that entire area was a 10v 2200uF Jamicon, as was the one on the other side of the heat sink toward the 35v 220uF that was bad as well. So I've got 7 caps to replace...!! In contrast, I have another PSU that requires *one* 16v 1000uF cap... hence my desire to overbuild reliability into this one for round 2...

You've obviously been around quite awhile, and I'm grateful for the opportunity to benefit from your experience. I got your list of reliable caps & mfgrs., thanks, and can't help but notice - given all the Jamicons I've been removing! - that Jamicon isn't on your list. What's their story, beyond the fact I've got a WHACK o' them to change in this PSU?! <^8# Some good, some bad? Spotty? They all SUCK?! <^8#

Thanks again, regards.

[everell]

Re: Bestec ATX-250-12Z rev D

Here is some helpful information for your Bestec ATX-250 12Z

https://www.badcaps.net/forum/showth...ec+ATX-250+12Z

[momaka]

Re: Bestec ATX-250-12Z rev D

Well, here is a cap diagram anyways... or perhaps I should rather call it a output power rail diagram.
https://www.badcaps.net/forum/attach...1&d=1471119216
For the 3.3V, 5V, and 5VSB rails, you can use either 6.3V or 10V caps (or 16V caps if you don't have anything else).
For the 12V and -12V rails, use 16V caps.

(IIRC):
Originally, the 3.3V rail had two 6.3V/10V 2200 uF caps. Same goes for the 5V rail. The 12V rail had one 16V 1000 uF cap and one 16V 2200 uF cap. Then the -12V rail had a 16V 1000 uF cap. And finally, the 5VSB had two 10V 2200 uF caps.

That said, the picture above is actually of my ATX-250-12Z after I recapped it. And on the 12V rail, I have one 16V 2200 uF Panasonic FC cap (the "fat" 12.5 mm on the top, next to the red choke) and one Panasonic FM 16V 1200 uF cap. I've kept the capacities on the 3.3V, 5V, -12V, and 5VSB rails the same, though.

can't help but notice - given all the Jamicons I've been removing! - that Jamicon isn't on your list. What's their story, beyond the fact I've got a WHACK o' them to change in this PSU?! <^8# Some good, some bad? Spotty? They all SUCK?!

Jamicon has the same problems that many other Chinese / Taiwanese brands have - often failing inconsistently and/or prematurely, especially when put in a environment that makes them work harder or closer to their limit (typically in a hot device or high-speed switching circuits). They aren't the worst, though (in my opinion / experience). But compared to the Japanese brands I listed above (with the exception to Samxon, which is TW), they simply can't compare in terms of quality. The Japanese brands above *will* actually meet their specs and not fail randomly.

That said, Jamicon does make decent fans.

You've obviously been around quite awhile, and I'm grateful for the opportunity to benefit from your experience.

You're welcome.
Yes, ever since I joined badcaps.net, I just couldn't stop reading the forums here - so much useful knowledge everywhere. At first, I barely knew anything about electronics. But after reading and reading for a few years, I know a lot more than before. So I guess now it's my turn to share that knowledge
Moreover, I'm still learning new things every day as people post their problems and we try to troubleshoot them. So it's a great community if you are trying to learn electronics.

[zx8401]

Re: Bestec ATX-250-12Z rev D

Here is a 300W version, this schematic may be usefull :-D
[/url]

[ptbo_bob]

Re: Bestec ATX-250-12Z rev D

Here is some helpful information for your Bestec ATX-250 12Z

https://www.badcaps.net/forum/showth...ec+ATX-250+12Z

Thank you! Many good pictures, much help. I can tell, I'm gonna like it here... <^8# I *really* like the repositioned cap adjacent to the heat sink! I thought I'd leave the legs a little longer, then angle it away from the heat sink, but THAT's a MUCH better solution! The traces you drill through; are they the same as its original position (I hadn't tried to trace it back yet, I'm guessing they are...) I have the rotary tool, the drilling/retrofit I can handle no problem...!!

Well, here is a cap diagram anyways... or perhaps I should rather call it a output power rail diagram.
https://www.badcaps.net/forum/attach...1&d=1471119216
For the 3.3V, 5V, and 5VSB rails, you can use either 6.3V or 10V caps (or 16V caps if you don't have anything else).
For the 12V and -12V rails, use 16V caps.

That's excellent! Thank you, that oughta lead me right back to the scene of the crash! <^8# And I'm going back with 16v's; I'm not doing THIS again!

(IIRC):
Originally, the 3.3V rail had two 6.3V/10V 2200 uF caps. Same goes for the 5V rail. The 12V rail had one 16V 1000 uF cap and one 16V 2200 uF cap. Then the -12V rail had a 16V 1000 uF cap. And finally, the 5VSB had two 10V 2200 uF caps.

That said, the picture above is actually of my ATX-250-12Z after I recapped it. And on the 12V rail, I have one 16V 2200 uF Panasonic FC cap (the "fat" 12.5 mm on the top, next to the red choke) and one Panasonic FM 16V 1200 uF cap. I've kept the capacities on the 3.3V, 5V, -12V, and 5VSB rails the same, though.

Okay, I'll definitely get back to you on what I *believe* mine had in it, before I go back in and recap it. There are a couple of 16v caps that didn't look bad, but when I took out all of those 10v 2200uF, four looked bad; *all 6* of them *were* bad. Should I cut my losses and change the last two as well, or isolate them and check them first for out of spec/ESR? Thoughts?

Jamicon has the same problems that many other Chinese / Taiwanese brands have - often failing inconsistently and/or prematurely, especially when put in a environment that makes them work harder or closer to their limit (typically in a hot device or high-speed switching circuits). They aren't the worst, though (in my opinion / experience). But compared to the Japanese brands I listed above (with the exception to Samxon, which is TW), they simply can't compare in terms of quality. The Japanese brands above *will* actually meet their specs and not fail randomly.


That said, Jamicon does make decent fans.

That's one helluv'an accolade for a capacitor manufacturer, wouldn't you say?! <^8#

You're welcome.
Yes, ever since I joined badcaps.net, I just couldn't stop reading the forums here - so much useful knowledge everywhere. At first, I barely knew anything about electronics. But after reading and reading for a few years, I know a lot more than before. So I guess now it's my turn to share that knowledge
Moreover, I'm still learning new things every day as people post their problems and we try to troubleshoot them. So it's a great community if you are trying to learn electronics.

I am! [...fade in the WayBack Machine...!] This *all* started with the oldest of my sisters, whose ol' single-core Celeron-based ECS mboard *always* had ghosts in the machine, y'know?! <^8# I eventually inherited it, and one tiny detail after another became apparent. One of my nieces undoubtedly *DROVE* a USB key into one, then the other, mboard-mounted USB sockets next to the PS/2 connectors, breaking off the guide, then curling up the bare contacts into a grounded, shorted mess... Anyway, I'd changed the power supply, 'cuz it seemed the one in it needed a couple of minutes to charge up the capacitors enough to get it going... Didn't help much. Fixed the shorting problem in the USB sockets... No big change... I'm sure it was better, just better sucky.

I pulled the mboard, don't remember what I was thinking, and *one* cap caught my eye - it was domed, and I don't even recollect *how* being like that was bad, any more... *AHA!* Could *this* be the ghost in the machine that had eluded me all this time? Well, I've done the software side of all of it for near 30 years, and this was/is a new investigation vector!!

Always wanted to do electronics as a kid, never got there - what comes around, goes around! So I changed the cap, and f*cked up a *frickin' MINISCULE* 4-gang 33 ohm SMD too small to be seen with the naked eye, and with too much solder (my old Radio Shack stuff with an older 40W Weller with a 1" chisel tip on it - GOOD FOR WHAT AILS YA!! <^8#) So now I'm waiting until I can order the correct replacement, then try to replace it successfully without messing up anything else, and *then*, and only then, will I fire it up and see if I get to call myself CapGhostBuster!! <^8#

Good God, *this* will be the death of me... after 30 or 40 more years of indentured service to the great Gods of everything electronic! <^8#

And now I check all the motherboards that pass through, and I'd been getting a newer computer ready for my mother, whose older one got more cantankerous than SHE is!! After "the enlightenment", I checked all the systems I have sitting around here, and two evidence bad caps; an e-Machines appears to need one... And the mboard in the computer I was prepping for my mom?! *7* No typo, *seven* capacitors!!

Holy CRAP! I don't know whether to say "OUCH!" or "Yowza!" I'll "go in" when I'm feeling stronger...

[ptbo_bob]

Re: Bestec ATX-250-12Z rev D

Here is a 300W version, this schematic may be usefull :-D
[/url]

Many thanks! It may be slightly different, and I'm a tad out of my league trying to read it, but things are slowly beginning to come together, and I can follow module to module and see if I can pull what info I need from it.

[zx8401]

Re: Bestec ATX-250-12Z rev D

The problem is often manufacturers change there mind so much, slight letter changes on a model number can mean big differences :-(.
If you look at the info you have, you can often see similar patterns and values of parts in there circuit blocks.
I did have a look for the exact diagram for you, but the net said "No" lol :-D
Hope you fix it, dont get too close when you plug it in he he :-D joking :-D.

[ptbo_bob]

Re: Bestec ATX-250-12Z rev D

The problem is often manufacturers change there mind so much, slight letter changes on a model number can mean big differences :-(.

Zackly! And then it takes legions of EEs, hackers & hobbyists to figure out the differences and gather together to share the info! <^8#

If you look at the info you have, you can often see similar patterns and values of parts in there circuit blocks.

Yeah, it should be a pretty good reference, even if it's not quite identical.

I did have a look for the exact diagram for you, but the net said "No" lol :-D

Yeah, me too; hey, a good project for me would be to take photos of the board, front & back, and then lay out the diagrams, then try to draw the schematic for it! (Oh, yeah; now who's getting brave?! <^8#)

Hope you fix it, dont get too close when you plug it in he he :-D joking :-D.

Rule #1: Never be standing in the area of the bomb crater!! <^8# (Isn't rule #0 then, always keep one hand in your pocket?!)

Thanks again, guys... I'm gonna do a comparison of the photo above and what's still in my PSU and try and extrapolate what else goes where, then post an annotated picture back here to get you guys to compare it to what you might have in yours and see if I've got it right.

Regards,
Bob. <^8#

[ptbo_bob]

Re: Bestec ATX-250-12Z rev D

(IIRC):
Originally, the 3.3V rail had two 6.3V/10V 2200 uF caps. Same goes for the 5V rail. The 12V rail had one 16V 1000 uF cap and one 16V 2200 uF cap. Then the -12V rail had a 16V 1000 uF cap. And finally, the 5VSB had two 10V 2200 uF caps.

That said, the picture above is actually of my ATX-250-12Z after I recapped it. And on the 12V rail, I have one 16V 2200 uF Panasonic FC cap (the "fat" 12.5 mm on the top, next to the red choke) and one Panasonic FM 16V 1200 uF cap. I've kept the capacities on the 3.3V, 5V, -12V, and 5VSB rails the same, though.

All of my relevant 2200s were 10v (I had to go back & check).The 16v 1000uF I removed tested fine, and I'm gonna try not changing the other two still there ('existing' in the annotated picture) and see if that resolves that. I also, I think I mentioned, have to change the 35v 220uF next to the other heat sink, it was also bulged, and tested bad. That's quite a set of caps to change in one PSU!

Thanks for everything. Oh, and I wanted to mention, that's one helluva photo! Spot on!!

[kc8adu]

Re: Bestec ATX-250-12Z rev D

since i have a cubic shitload of rubycon 1200@16 zl i use those in all positions needing a 10mm cap.i still get bestecs in to recap.though not like i used to.
the esr is the most important spec and the can size mostly determines that.
not to mention the zl is lower esr than anything in that can size than what came in these units.
i have these units out in the worst possible environment one could use them in and they dont fail again unless hit by lightning.only then do i get them back along with the rest of the carnage.

[momaka]

Re: Bestec ATX-250-12Z rev D

Yeah, me too; hey, a good project for me would be to take photos of the board, front & back, and then lay out the diagrams, then try to draw the schematic for it! (Oh, yeah; now who's getting brave?! <^8#)

That's actually a pretty good idea if you are trying to get better or still learning to draw schematics. I wouldn't suggest doing it from pictures, though. It's much easier if you have the PSU in one hand and a pencil in the other (yes, a *pencil*... and preferably with a big-ass eraser, because you will be drawing and re-drawing various parts of the circuit until it looks right.)

I actually did this for the 5VSB section of several PSUs, all employing a 2-transistor design.
https://www.badcaps.net/forum/attach...1&d=1406952554
https://www.badcaps.net/forum/attach...1&d=1407035562
(for the full threads, look up CyberLink CWT-320ATX or TurboLink LC-A420ATX, if interested)

While the first schematic above took a long time to draw, the second one wasn't too bad, simply because I copied the first one and then just modified it accordingly with the second circuit.

That's quite a set of caps to change in one PSU!

Better than a HP Compaq DC5000 motherboard! On those, I've seen nearly every cap in every position blown. That's nearly 30 caps we are talking about here! Most I worked on needed at least 20 of those changed.

Oh, and I wanted to mention, that's one helluva photo! Spot on!!

Glad you found it useful.