RandomStranger wrote on 2022-11-16, 19:39:A coworker planned to throw out a Compaq Deskpro 50M and I said not without me checking it out. Dirty with spots of dust here an […]
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A coworker planned to throw out a Compaq Deskpro 50M and I said not without me checking it out. Dirty with spots of dust here and there. I knew nothing about these PCs and hoped it'll be a 486 VLB system, since I'm planning to build one for a while I didn't want to pay the price of the mainboards that were available. Compaq however never disappoints when it comes to how disappointing it can be. I got my 486DX2, in an almost completely proprietary EISA PC.
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And it doesn't boot. Seems to turn on, but no floppy drive self test or beeps, the hard drive (a Conner CP3301) spins up, but that's about it. Looks more trouble than it's worth. At best I can get a CPU, a stick of RAM, a sound card, a hard drive and an optical drive out of it, but all of that needs testing.
I've also picked up 5 boxes of 3.5" floppies and a still sealed OEM DOS.
You got a good complete set of hardware in this Compaq Deskpro /M. Your issue is in power supply and unlike other power supply, power supply is a board replacement. Power supply spares is *Unobtainable* now. I had to buy another /M computer with intact power supply. In your case, you have to rebuild the power supply capacitors or use ATX power and 20 pin extension method.
During meantime, I researched and obtained a working pinout of the deskpro /M motherboard's power connector. It is same 20pin ATX plastic plug and I was able to power up /M using a male to female ATX harness by rearranging the pinout at female connector end and leave 3.3V off and use ATX power supply instead. Like this:
https://www.ebay.ca/itm/185452130344?hash=ite … ABk9SR6DavJeWYQ
Here's the pinout from my article:
This is for Deskpro M series PSU pinout measured on the motherboard's.
*N/C X X pin 1 (one), still unknown purpose and has connection, no voltage.
-5V X X <---------Power Good signal.
GND X X -12V
GND X X GND
GND X X GND
GND X X GND
+5V X X +5V
+5V X X +5V
+5V X X +5V
+5V X X +12V
N/C X X +12V
N/C X X N/C
Great Northern aka Canada.