Re: IBM type power supplies

["John E. Becker, Jr." <c621825@cclabs.missouri.edu>]

Paul Holton wrote:
> 
> I have an IBM type power supply that I would like to convert to another
> use. The problem is that I can't get but a momentary output because of, I
> suspect, the Orange "Power Good" lead is feeding back that there is no
> power at the output (+ and -) 5 and 12 volt leads when it is just sitting
> there on the bench (no load) but turned on. Is there anyway around the
> "power good" feedback so I can get an output of 5 and 12 volts?
> Thank you for your help
> Paul

Try adding a load (like an old PC floppy drive or two) and then test it.

Most computer power supplies require a certain load before they will function 
properly.  The really old ones must supply at least 60% of maximum rated current 
to do so, but most newer supplies are "pre-loaded", so almost any current level 
can work.  However, even on these supplies, when there is little or no load on 
the power supply, it will either turn on-and-off momemtarily or supply the wrong 
voltages.

At least in the power supplies I've seen, the power supply will still work 
without the power good line connected to anything.  I use a PC power supply to 
power an IDE hard drive for my IIgs, and it works fine without a power feedback.

-- 


John E. Becker, Jr.
E-mail:  c621825@cclabs.missouri.edu
WWW:  http://www.cclabs.missouri.edu/~c621825


              *****LEGAL NOTICE TO ALL BULK E-MAILERS*****

NOTICE TO BULK EMAILERS:  Pursuant to United States Code, Title 47,
Chapter 5, Subchapter II, section 227, any and all nonsolicited commercial
E-mail sent to this address is subject to a download and archival fee in
the amount of $500 US.  E-mailing denotes acceptance of these terms.