Need Bestec 450W Power Supply Schematic Diagram

[Galib]

Sorry for the late Reply . Because Electricity was not for a long time in my area . And it was a bad day for me . I could not repair any one of two power supplies !!!

Bestec ATX-250-12Z :
It's Fuse, Bridge and Big Mosfet has gone . And you know Mosfet does not go alone - it takes feedback IC also . It's Repairing Cost will be too high . So, It could not be repair .

Another Chinese Power Supply :
It's Start-up +5VSB section was gone . I have Replaced 2N60 Mosfet and any other bad components . But +5VSB Section is not Starting-up !!! There is all the parts are 100% OK . But still this shit is not starting-up . I found the Gate voltage is 0V whether 18V Zener is still there . I don't know why it is showing 0V . But the Gate Resistor 1MΩ + 1MΩ are OK .

Then I found the main Filer Capacitors have 300V where I need at least 310V to run a SMPS circuit . Then I changed the both Capacitors, dis-charging Resistor, NTCR, Bridge Diodes etc . But still it is holding 300V . It is not increasing to 310V anyway .

Then What is the problem there ? Is it the problem in 310V or in +5VSB section ?? Does a SMPS start-up in 300V ?? I am totally confused . Can you give me some feedback to recover this ....... please .

[c_hegge]

I think 300V should be OK. The voltage across the caps should be your mains voltage x 1⅓ (or 2⅔ when the PSU is set to 110V)

I think India uses 230V (so the voltage should be about 307V), however, Europe uses 220V, so the voltage there would be 293V, and they work there. I'd say the problem is more likely to be with the 5vsb rail.

[Galib]

Thanks c_hegge . Now I have changed all caps, Optocoupler and even Transformer also . But still same result . Now one thing to do - 1MΩ + 1MΩ will be replaced with single 2MΩ 1/2W resistor . If it starts then well, otherwise it needs to be thrown !! Why this kind of No-Sense Problem rises in PSU ?? Have you faced such kind of problem before ?? What is treatment in No-Sense condition - still it is unknown to me !!!

By the way - can you give me a referral link for registration at http://www.badcaps.net . I tried several times to register there . But Every time it shows Registration Denied !!

Thanks

[c_hegge]

yup http://www.badcaps.net/forum/register.php for the forum and http://www.badcaps.net/store/create_account.php for the store

If replacing the major components doesn't fix a problem, then it probably has small components which are bad. Personally, I don't bother repairing problems like that. It's just too much trouble for me to worry about, especially when there are relaible, affordable replacment power supplies available here (although I'm not sure whether that's the case in India).

[Galib]

After working several hours, when the device does not work, Then every Repairer feels worry about that, which is not only for me, it happens for all repairer in any kind of profession !!! That is the matter . In this Forum Which PSU are described, they are not available in India . That kind PSU comes with some imported PC like DELL, HP, COMPAQ etc .

I tried several times to register with that link before . But after submitting all information it shows registration denied . I don't know why !! Are you a memeber of badcaps.net ?? If you are a member of badcaps.net then give me a Invite friend request from your profile page - thats I wanted from you .

Thanks

[shovenose]

I don't think that Badcaps.net Forum has an invite thing...
I was looking at my profile and couldn't find the link.
http://www.badcaps.net/forum/member.php?u=22365

[Galib]

hmm, .... I see c_hegge is also there in your friend list . But I don't know, why I was unable to register there !! Then shovenose give me favour ..... Download the PDF file from the below link and share it here .

http://www.badcaps.net/forum/showthread.php?t=8878

Thanks

[Th3_uN1Qu3]

India could have been banned due to spammers. PM c_hegge your IP address and i'm sure he can talk to Topcat and get your IP removed from the blacklist so you can register.

Anyway, file is attached.

[Galib]

Thats nice and thanks for sharing the file .

[c_hegge]

The friend request on badcaps.net is only for existing members. It's not a way to get around IP address bans.