Looking for a Bestec ATX-300-12E circuit Diagram

[hkqq2010]

Re: Looking for a Bestec ATX-300-12E circuit Diagram

This schematic was drawn of the Bestec ATX-250 12Z, but is very much like your power supply. The 5vsb circuit is similiar for Bestec ATX-250 12Z, ATX-300 12E, and ATX-300 12Z. All use the A6351A pwm chip..

I have a Bestec ATX300P5WB, it is always blown up the fuse. Too bad ah....
After I isolated the 5Vsb circuit, it now stop blown up the fuse ...
But unfornately, it is different from your provided circuit, it used TNY276PN power chip.
Anyway, I will continue to try fixing it up .... Thanks for your circuit.

[everell]

Re: Looking for a Bestec ATX-300-12E circuit Diagram

This schematic was drawn of the Bestec ATX-250 12Z, but is very much like your power supply. The 5vsb circuit is similiar for Bestec ATX-250 12Z, ATX-300 12E, and ATX-300 12Z. All use the A6351A pwm chip.

As for your question "pins 1, 2, and 3 welded together", you are probably looking at the pin numbering wrong on the bottom of the board. Pins 7 and 8 are tied together, and pin 6 is not connected to anything inside the chip. Therefore what you are probably seeing is pins 8, 7, and 6 tied together. Look at it again and let us know what you find.

[Drexter]

Hi guys,

I have a burned Bestec power supply, the problem was at the IC 8, it shorted due to humidity and burned itself, I was able to see the inscription on top of it and it says, A 635 M, not very sure about the M, and looking at a past thread I saw that someone said that this power supplies had the A6351 pwr chip, so i figured it was the one it burned out on my power supply. But after I reviewed the datasheet I saw that pin 1 is Source, pin 2 is GND, and pin 3 is Vin. Knowing that, before i solder it i saw that on the track where they are supposed to be solder is a continuos one. what I mean is that if i solder them pin 1, 2 and 3 will be shorted, pin 4 is separetly. So this is where I ask you guys, would it be that the chip I bought is not the right one? not the A6351, or the track is bad due the burn out?. Cause it doesnt make sence to me that the pins 1,2, and 3 get welded tougether. Thats why I was looking for a Diagram for the power supply but I just dont find it anywhere. Any suggestions?

By the way, english is not my native tounge so please bare with me if I dont express myself correctly or with the proper terminology.

Thanks,

Paul