[Coco] FD-502 controller problem

Gene Heskett gene.heskett at verizon.net
Fri May 19 09:12:37 EDT 2006

Charlie wrote:
> Hello CoCo fans!
> I have a FD-502 disk controller that is giving me a bit of trouble. A DSKINI
> on drive 0 gives an IO error
> when the "clicking" sound from the drive steps up to a faster rate. (I hope
> I explained that right.) DSKINI on
> drive 1 works just fine. Otherwise the controller seems to work fine for
> loading games and apps.
I think the more likely problem is a lack of lubrication of the drives 
head slider mechanism.  A half a drop of 3in1 on the slider rods can do 
wonders there.  Also, if that drive has the spiral screw drive, with a 
smallish motor on the back of the drive turning that screw directly, 
(newer drives only, say made since 1991 or so) the threads of the screw 
can pack full of dirt and old dried grease over the time periods these 
drives have been around.  That will take something like a toothbrush and 
solvents to clean that up, and a drop of oil or light grease when its 
all cleaned up.

> I opened the controller and cleaned all the contacts. I can see that some of
> the contacts have the tin worn off and
> are looking the color of copper and not silver. Should I re-tin these with
> solder?

Not really, as long as they're clean.  A very gentle scrubbing to 
brighten up the copper will leave a better connection than the tin oxide 
would be in 3 months if you re-tined them.

> Besides the worn contacts would anyone else know what could be wrong with
> the controller?

Cheers, Gene

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