Bestec "12Z" returns for polycaps

[everell]

This is a Bestec ATX-250 12Z. Lots of them out there. I fixed this one some time ago. I decided to modify it using polycaps in the pi output filters on the 12, 5, 3.3, and 5vsb outputs. I used United Chem-Con PSG series 2200 uF/16 volt polycaps. After the modification, all is working well.....so far.

While taking a few pictures of the 12Z sporting its new polycaps, I had a helper (kitty) who wanted to check out the modification. After looking it over, sniffing it out, she gave her approval and moved on.

[stj]

Re: Bestec "12Z" returns for polycaps

well done, but in europe the poly's would cost more than the psu.

[Stefan Payne]

Re: Bestec "12Z" returns for polycaps

well done, but in europe the poly's would cost more than the psu.

No, Reichelt has Kemet A750.

[Per Hansson]

Re: Bestec "12Z" returns for polycaps

Out of curiosity do you have a scope to check the ripple with caps close the the originals and then these new polymers?

[mockingbird]

Re: Bestec "12Z" returns for polycaps

Very nice.

Can you please post an updated pic of your PSU stash in your attic?

[everell]

Re: Bestec "12Z" returns for polycaps

mockingbird - I think you are jealous. OK, here is some pictures of what is in my attic right now - just took these pictures. All of these were on the way to the garbage. This is my collection since starting this hobby in 2009.

[mockingbird]

Re: Bestec "12Z" returns for polycaps

Amazing!

Thanks

[PeteS in CA]

Re: Bestec "12Z" returns for polycaps

Ah ... power supply porn ......

[eccerr0r]

Re: Bestec "12Z" returns for polycaps

holy crap...
were they all dead and repaired?

[Sparkey55]

Re: Bestec "12Z" returns for polycaps

I hope you do not get mice! Or will they hang themselves?

[everell]

Re: Bestec "12Z" returns for polycaps

As for the power supplies in my attic, I submit the following thoughts for your consideration.

I have been through a two year electronics tech school (United Electronics Institute, Louisville, KY), and I have completed all of the courses and have a 2 year associates degree in Digital Electronics from a two year junior college. No where in all of this schooling was any time devoted to training in computer power supplies.

If you want college level training on computer power supplies, the place to get it is right here on Badcaps.net. Colleges charge a hefty price for lab work which accompanies the lecture class. "Lectures" on computer power supplies on Badcaps.net are FREE. Nearly all of the power supplies I use for my lab work have been free. So I think that I have had an opportunity to have a college level course for free, and the lab portion has also been free. I think ALL of us will have to admit that we have learned a lot from this forum. So anytime I find a free power supply, I grab it and stash it in the attic, using what I want when I want. I also consider it a hobby....a very cheap hobby. As for any parts I have to buy, I consider that cost to be very CHEAP compared with the cost of a college lab fee.

No, I do not fix computer power supplies to sell, or as a repair service. That would imply warranties and liabilities.

[everell]

Re: Bestec "12Z" returns for polycaps

Out of curiosity do you have a scope to check the ripple with caps close the the originals and then these new polymers?

I don't have pictures showing the Bestec with the original caps, but here are some pictures of the +5 and +12 volt outputs with the new poly caps. On each output I looked at no load condition, then with my Biostar M6VLQ pentium 3 test mother board. With no load you can see the spikes at the switching frequency. With the mother board as a load you can see all kinds of things between the spikes.

[dmill89]

Re: Bestec "12Z" returns for polycaps

I don't have pictures showing the Bestec with the original caps, but here are some pictures of the +5 and +12 volt outputs with the new poly caps. On each output I looked at no load condition, then with my Biostar M6VLQ pentium 3 test mother board. With no load you can see the spikes at the switching frequency. With the mother board as a load you can see all kinds of things between the spikes.

Those are some ugly spikes. Too bad you don't have a before, but I would suspect it is substantially worse with the polys.

Here are some comparisons, I used the same 50mV and 2uSec scales noted on your scope shoots, this is on an ECS L4VXA2 motherboard running memtest86+.
Antec BP350 (FSP):
12V:


5V:


3.3V:


L&C (Rosewill Branded) LC-8400BTX (Recapped with Chemi-Con KY/KZE):



12V:


5V:


3.3V:



PC Power & Cooling Silencer MKIII 600W (Rebadged Seasonic M12II):

12V:


5V:


3.3V:


VIO (Leadman) KY-550ATX (gutless wonder):
12V:


5V:


3.3V:



Only the piece of crap VIO(Leadman) has spikes as bad as that 12Z with polymer caps, though the 12Z is cleaner overall.

[Per Hansson]

Re: Bestec "12Z" returns for polycaps

Thanks everell

[goodpsusearch]

Re: Bestec "12Z" returns for polycaps

Very interesting, thank you both for posting!

[momaka]

Re: Bestec "12Z" returns for polycaps

I think ALL of us will have to admit that we have learned a lot from this forum.

Yes, sir!

All of my knowledge regarding switchmode power supplies and how to repair them has come from here (some of it indirectly through links to other websites, but nonetheless links that I found on BCN a long time ago).

So yes, HUGE THANKS to Topcat for badcaps.net!
And of course everyone who has contributed here.

mockingbird - I think you are jealous.

And he may not be the only one that is jealous

OK, here is some pictures of what is in my attic right now - just took these pictures. All of these were on the way to the garbage. This is my collection since starting this hobby in 2009.

WOW!

I'm saving these images to my PC for reference now. That way, if anyone (friends or family) tries to tell me I have too many PC parts (especially PSUs), I can conveniently show them these pictures and what "too many" should mean.

Also, everell , I think you should go sign up the Guinness World Records book for person with biggest collection of PC power supplies.
No seriously, you should consider it, though. There's probably every low and mid-range PSU in that collection.

By the way, try to power on these fixed PSUs once every year or two. Otherwise the caps might age much faster in them.

Those are some ugly spikes. Too bad you don't have a before, but I would suspect it is substantially worse with the polys.

Agreed.
I think many of these cheaper and/or older PSUs are simply not made for poly caps. I find that the only exception is the 5VSB rail, due to being flyback/discontinuous topology. But PSUs like these are often better off even with general purpose caps than polymers.