Can I modify Power Supply

[Paul Komski]

I have a 2nd-hand Tatung(OEM PC)on which the power supply has failed twice in 10months and this time I can't seem to get a replacement. I've been waiting 2months for it now). It has weird "hybrid" motherboard power connectors (sort of between a Baby AT and an ATX and yet it is not an LPX either. It has the normal 12pin AT-type socket but in addition it has a small 3pin socket for PS_ON, STB5V and GROUND. The motherboard has no 3.5V connections; the CPU voltage being selected by jumpers.

If I use a brand-new ATX Power Supply and just fit the correct wires to the old AT-type sockets I think everything should work OK. There is just one thing I'm not sure about and that is (apart from not using the orange 3.5V wires and blanking them off) whether the brown 3.5V_Sense wire can also be blanked off without affecting the power supply as a whole. I have been surfing around trying to find out what this wire does without success.

What does the sense wire do and does anyone know if I can procede as above without trepidation!? or where I can buy a new replacement.?

[This message has been edited by Paul Komski (edited 10-13-2001).]

[yawningdog]

I think you should be okay as long as you can duplicate the power pinouts on you old power supply. If I had to guess, I would say that 3.5v sense is used to detect short circuits in that line and prevent destructive overheating in the event of one. (Although I'm dubious as to the amount of heat generated by a mere 3.5v) Indeed, I've considered the ATX to AT conversion myself just for experimental reasons. Good luck, and report back with your findings.

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Give a man a fish, and you feed him for a day. Teach him to use the net, and he wont bother you for weeks.

[Paul Komski]

Thanks "Y-Dog".

I went ahead and cut the ATX wires and re-inseted the twelve obvious ones into the P8/P9 12pin sockets. The triple connection for the suspend was a bit "heart in the mouth" since it wasnt obvious from the motherboard which was Pin#1 and which was Pin#3! But I thought (from the bad motherboard diagram) that I knew and ploughed ahead. Turned everything on and waited for a puff of smoke - but lo and behold everything worked perfectly. All the 3.5V plus the 3.5V-sense were untouched and I just left them connected the original ATX socket and covered the ends with insulation.

I since found that you can buy ATX to AT conversion cables - though not many sites stock them. After all its just a matter of two/three pieces of plastic and a few wires!

Best wishes. But that brown wire is still bugging me.

[This message has been edited by Paul Komski (edited 10-16-2001).] http://www.PCGuide.com/ubb/wink.gif

[This message has been edited by Paul Komski (edited 10-16-2001).]