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Old 02-28-2009, 07:10 PM   #1
bojoe
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Smile Can a Bestec be made good?

Assuming that a Bestec 300 has not yet gone bad, (ie., volts still correct), can it be made "good" by recapping, or is it inherently bad by design?
I have 6 systems (Emachine\Gateways) running on Bestecs.
Thanks,
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Old 02-28-2009, 08:07 PM   #2
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Default Re: Can a Bestec be made good?

Inherently bad design, only way you can make it semi-good is use *premium* caps in there, especially one key small cap that caused overvolting.

Other than that, I rather use a PSU with a true PWM IC built into one IC for standby power.

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Old 03-01-2009, 06:57 AM   #3
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Default Re: Can a Bestec be made good?

So this problem is not limited to the 250W model only? Damn I better inform a good friend of mine to get rid of his 300W Bestec immediately.

EDIT: Wizard you got any pics of a Bestec? I would like to know which cap is the one that causes overvolting of the +5VSB.

Last edited by Leopard; 03-01-2009 at 06:59 AM..
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Old 03-01-2009, 10:08 AM   #4
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Default Re: Can a Bestec be made good?

i recap these all the time.the "killer"cap is a [email protected] in +5stby.
it is in several locations depending on the rev.
i use a [email protected] fc
the [email protected] gets a [email protected] pw.newer ones use a [email protected]e get a [email protected] fm.
all the rest get [email protected] mbz since i have an inexhaustible suppy of [email protected] mbz on +12 and -12.
they are just fine afterwards.would not put one in a server but i have a 300 in this box now.its a amd fx60 dualcore with 4gb ram and 6 146gb 15k scsi in raid 5.
been in it 2 years since i recapped it.i have ben keeping a close watch on it but as i suspected years ago they are fine when good parts are used.they also have remote sense on +3.3 and +5.

Last edited by kc8adu; 03-01-2009 at 10:10 AM..
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Old 03-01-2009, 01:45 PM   #5
Wizard
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Default Re: Can a Bestec be made good?

Wattage doesn't determine the issues, the brand do. Bestec = trash.

Recapping it with quality capacitor helps but important to replace FAN with a ball bearing fan so you don't get a overheat on your hand (happened to me!).

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Old 03-01-2009, 02:03 PM   #6
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Default Re: Can a Bestec be made good?

The guys on this forum give good advice concerning the need for good capacitors - and replacing problem brands. Another problem with the Bestec is the 5VSB design. You can look at the pc board and see that most of the heat discoloration is in the 5VSB circuit. Those models using the two transistor 5VSB have no protection against overvoltage/overcurrent problems. My solution was to remove the transisors and associated circuitry and install a DM311 chip on a seperate piece of perf board. This chip provides the needed overvoltage and overcurrent protection. How to do it?...see my thread posted a few days ago titled Bestec ATX250-12E up and running. I posted photos and circuit diagrams. This modification may not be necessary if a later model has an IC for the 5VSB circuit. Caution: be sure the DC voltage has discharged from the two big capacitors before working on this PS, they charge to 332 volts and will bite!
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Old 03-01-2009, 05:13 PM   #7
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Default Re: Can a Bestec be made good?

I see I need to recap or replace all the Bestecs - very soon. They are not really servers, but they all are Point-Of-Sale stations, and it's awful when they go down.
Thanks for all the answers..
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Old 03-01-2009, 05:34 PM   #8
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Default Re: Can a Bestec be made good?

Buy a good PSU like seasonic and replace one POS and rebuild this PSU, then swap this repaired PSU in another POS. so on.

Cheers, Wizard
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Old 10-06-2010, 03:16 PM   #9
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Default Re: Can a Bestec be made good?

If you do some research, you may find out that the 5vsb flaw is in the Bestec units marked "250-12E". From what I have heard, the 300w 12E units have much better standby circuits. As long as your emachine systems don't have the 250w 12E Bestec units in them, then you should be okay.
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Old 10-06-2010, 06:45 PM   #10
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Default Re: Can a Bestec be made good?

my friend gave me a best tec 250 12e for free,its a great power supply, i took it apart and no bulging caps, it powers a athlon xp system now with bulging GSC caps on the mobo theyve been bulged for a couple years but haven't blown up, my freind also gave that board for free, its a albatron km266pro he said he saw smoke come out of a ram slot but ive never had problems with it, the chipset fan seized so i put some 10w 30 in it and its been good for 2 years. iam gonna run it till it blows.
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Old 10-06-2010, 07:04 PM   #11
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Default Re: Can a Bestec be made good?

Quote:
Originally Posted by BigTroll View Post
my friend gave me a best tec 250 12e for free,its a great power supply, i took it apart and no bulging caps, it powers a athlon xp system now with bulging GSC caps on the mobo theyve been bulged for a couple years but haven't blown up, my freind also gave that board for free, its a albatron km266pro he said he saw smoke come out of a ram slot but ive never had problems with it, the chipset fan seized so i put some 10w 30 in it and its been good for 2 years. iam gonna run it till it blows.


WARNING! when a 12e blows it takes out the mobo with it!!!!

you better not do that. for future reference, it is generally not advised to Run it til it blows". especially the 250-12e. i guarantee a 18v 5vsb will fry your mobo.

i would personally find another psu to replace it with. recap at your own risk.
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Old 10-06-2010, 07:18 PM   #12
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Default Re: Can a Bestec be made good?

Quote:
Originally Posted by ratdude747 View Post


WARNING! when a 12e blows it takes out the mobo with it!!!!

you better not do that. for future reference, it is generally not advised to Run it til it blows". especially the 250-12e. i guarantee a 18v 5vsb will fry your mobo.

i would personally find another psu to replace it with. recap at your own risk.
lol, did you see that article called death of a gutless wonder http://www.jonnyguru.com/modules.php...Story&reid=154 its hilarious. actually i took it back out and put in a my old 300watt enhance it has one slighty bulged cap, my friend got all mad hes like the best tec has no bulging caps and you put in one with bulging caps i was like yeah but what about this article lol.
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Old 10-06-2010, 10:39 PM   #13
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Default Re: Can a Bestec be made good?

Any bestec that has a model of ATX-xxx-12E (xxx=wattage) has the 5vsb. The 12Z and others are fine and not affected.
Do not use a psu with bad caps. It may be serving up unclean power with out of spec ripple. And a capacitor thst is even slightly bulged is as bad as one thats leaked out brown ooze. Its either perfect in good condiotion or completely failed (bulged or blown)...
All or nuthin with these fuckers
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Old 10-06-2010, 11:09 PM   #14
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Default Re: Can a Bestec be made good?

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Originally Posted by shovenose View Post
All or nuthin with these fuckers
Actually no. There are lots of caps that fail without the slightest bulge.
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Old 10-06-2010, 11:21 PM   #15
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Default Re: Can a Bestec be made good?

i had some generic 1997 AT Power Supply today, it was 230 watts i opened it and IMEDIATELY SAW CapXon Primaries which gave me a slight bulge in my pants and some excentment but then when i got over to the secondary side i saw FUHJYYU and My Rocket took off, i mean this much quality! in a power supply made 12 years ago. and knock on WOOD there were no bulging caps and it works great!
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Old 10-06-2010, 11:31 PM   #16
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Default Re: Can a Bestec be made good?

If you are getting a bulge over caps then perhaps an appointment with a psychotrickerist is in order.
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Old 10-06-2010, 11:33 PM   #17
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Default Re: Can a Bestec be made good?

okay maybe i exagerated a bit.
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Old 10-06-2010, 11:41 PM   #18
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Default Re: Can a Bestec be made good?

Quote:
Originally Posted by BigTroll View Post
i had some generic 1997 AT Power Supply today, it was 230 watts i opened it and IMEDIATELY SAW CapXon Primaries which gave me a slight bulge in my pants and some excentment but then when i got over to the secondary side i saw FUHJYYU and My Rocket took off, i mean this much quality! in a power supply made 12 years ago. and knock on WOOD there were no bulging caps and it works great!
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Old 10-07-2010, 12:24 AM   #19
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Default Re: Can a Bestec be made good?

Quote:
Originally Posted by weirdlookinguy View Post
Actually no. There are lots of caps that fail without the slightest bulge.
True
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Old 10-07-2010, 08:40 AM   #20
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Default Re: Can a Bestec be made good?

I meant that they work or dont. Theres no sort of working with capacitors
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