PC power supply conversion

[NI3S]

I've seen instructions online a few places for converting/using old PC power supplies for ham stations. Has anyone ever done this with reasonable success? I'd guess additional filtering may be required on the output as well as some method of keeping RF from getting back into the supply.

[AD2U]

You need to draw something on the 5V rail to keep the 12V rail stable, like 4A using a 1.25 Ohm 25 Watt resistor.

[KB3SDS]

I used to just run an old HDD off the one of the molex to keep the supply running, they usually shut down if there is no load on +5v. Other then that you short "power on",green, to ground to juice it up.

[KJ4ODU]

I have booked marked a site that uses like 6 Computer Power Supplys to make a tower, and to have like 30 amps from what it said.

you can always find CPU Supplys from like the recycling dumps. etc Free

http://w5jgv.com/tower_of_power/index.htm

[W9GB]

Google St. Louis Switcher ... numerous articles have been written since this QST article.
Copy of that article:
http://www.angelfire.com/planet/als_...e_switcher.pdf

IF you have an ARRL membership -- these articles are freely available to you!

The St Louis Switcher
May 2002 QST, page 35
Matt Kastigar, N0XEU
http://p1k.arrl.org/cgi-bin/topdf.cgi?id=101842&pub=qst

Building the St Louis Switcher (sidebar to The St Louis Switcher)
May 2002 QST, page 36
Heron, George, N2APB
http://p1k.arrl.org/cgi-bin/topdf.cgi?id=101853&pub=qst

Technical Correspondence
Sept 2003 QST, page 73
Steven D. Katz, WB2WIK
Re "The St Louis Switcher"
http://p1k.arrl.org/cgi-bin/topdf.cgi?id=104757&pub=qst

Technical Correspondence
Jan 2004 QST, page 72
Tasos Thomaidis, SV8YM
More on the "St Louis Switcher"
http://p1k.arrl.org/cgi-bin/topdf.cgi?id=369&pub=qst

[VK2TIL]

VK5JST has written some very good notes on modifying computer power supplies;

http://www.users.on.net/~endsodds/safe.htm

[KJ6CLX]

I tried doing this with a 500W ATX power supply that supplied 34A (or at least that's what the case said) anyway I was using a FT-7800 and it powered on but when I keyed up even on low power it shut off so I don't think it quite works so well.

[W9GB]

I was using a FT-7800 and it powered on but when I keyed up even on low power it shut off so I don't think it quite works so well.

Stray RF will cause many switch-mode power supplies (SMPS) to "shut down".
I think you will find that the 34 Amp rating was for the + 5 VDC rail, not the +12 VDC output. Some of these SMPS have an adjustment pot on PC board to raise the output voltage to 13.8 VDC.

SMPS have HV inside (> 300 VDC) and while "state of the art" -- they are complex for the average amateur to understand or repair.
Even though Linear Mode supplies are heavy (power transformer), they are far simplier for the average amateur to repair.

w9gb

[N0REK]

I used the information on this web page as a starting point for doing mine...

http://www.mbeckler.org/powersupply/

The power supply I used is this one: http://www.newegg.com/Product/Produc...82E16817341020

It has been discontinued (it has been a whole month since I bought it...) but there are likely similar ones available.

I added 2 pair of powerpole connectors to the case (where the wires used to come through) which are attached to the 12V rail (17A).

I use my IC-2200H on it and have had no shutdown problems.

N0REK

[KB3SDS]

I'm thinking over the weekend i might build a breakout box with a female ATX connection on it. That way i can plug in any ATX PSU i have laying around and give me the connectors, meters, resister, ect i need in one shot.