[Coco] FD-50X series power supplies

Steven Hirsch snhirsch at gmail.com
Thu Oct 29 12:30:54 EDT 2009

On Thu, 29 Oct 2009, Chad H wrote:

> Well the replacement candidate PSU units I found are not the originals, they
> aren't even old they're brand new.  I wouldn't even know where to begin
> looking for those originals.
> I'm running the original FD-502 Drive 0 plus a 2nd 5.25 360k drive pulled
> from old PC-XT and installed a small 12vdc cooling fan just to be safe so I
> believe I'm running what the power supply was intended for.  I was just
> wondering about the minimum power requirements for this setup.  A
> car/truck's 12vdc system would supply way more than enough power (but what
> about the 5vdc?) I just want to make sure the replacement is rated at enough
> amps to run the dual floppy+fan setup.  The PSU unit's I'm looking at are
> designed for PC 4-pin Molex power applications  (Same hookup as the PC-XT
> drive, would just have to match wiring for the original 502 drive with mini
> "3.5 floppy" type connector.)
> Here are 2 candidates I'm looking at right now.
> Internal?  Trying to find out size dimensions on these.
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270461125059&ssPageName=A
> DME:X:RTQ:US:1123
> External.. http://www.svc.com/pa-ad-ul.html

Either of those should be fine for running floppy drives.  Just be careful 
not to confuse +5 and +12 :-).  I've been working with electronics for 
years, and still have managed to let the magic smoke out things in just 
such a manner!

In particular, when retrofitting one of those 4-pin Molex cables to a 
power supply, NEVER assume that RED=5V and YEL=12V!  I have seen PC 
supplies come from the manufacturer with these colors crossed.  Mind you, 
the _pinout_ on the connector was correct - only the colors were crossed. 
The problems comes when you cut the cable off a scrapped supply for 



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