Hacking Power Supply

I am taking the plunge and building a Work Bench Power Supply from a PC Desktop power supply.

The guy in the video suggest that a approximate 0.5 amp load be put on the 5 volt rail (12 volt rail on newer) of the switching PS in order to stabilize it.

This diagram shows how he suggests putting it together.

What say you?

Top Replies

Former Member over 13 years ago in reply to billabott +2

Of the dozens of PC ATX-type power supplies I've used in analog, digital, and electrochemical circuits, I've never needed to add a "stabilizing" resistor. Basically, ground out the green wire, and the…
R_Phoenix over 13 years ago +2

The resistor isn't to stabilize the PSU, but rather give the system a dummy load on the 5v that helps "pull up" the 12. Taking the green wire to ground will still turn it on, but then messure the voltage…
terryking over 13 years ago in reply to R_Phoenix +1

Power resistors are hard to find. Just use a 12V Automotive tail light / side light bulb on the 5V supply. It will be bright enough to function as a "Pilot light" and will last almost forever at 5V...…

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billabott over 13 years ago

Hooray for Harbor Freight and Ryobi Power tools!
I finally used my Ryobi DP120 drill press and knock out punch kit.
First I had to drill a 1/2" hole in the power supply lid, then knock it out
to 3/4", then dremeled down the rough edge. It is perfect. Looked thru my TV repairman's collection of V-tubes to find a good looking Tung-Sol (even says Made in the USA) 9 pin 12xx7. I am only going to hook up the heater. It will light up when the switch is on!
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billabott over 13 years ago

Hooray for Harbor Freight and Ryobi Power tools!
I finally used my Ryobi DP120 drill press and knock out punch kit.
First I had to drill a 1/2" hole in the power supply lid, then knock it out
to 3/4", then dremeled down the rough edge. It is perfect. Looked thru my TV repairman's collection of V-tubes to find a good looking Tung-Sol (even says Made in the USA) 9 pin 12xx7. I am only going to hook up the heater. It will light up when the switch is on!
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