troubleshooting an SA-400 disk drive

From: Eric Chomko <vze2wsvr_at_verizon.net>
Date: Wed Jun 11 07:31:00 2003

Peter Turnbull wrote:
>
> On Jun 10, 22:23, Eric Chomko wrote:
> > I have been monitoring this new problem for a few days. Actually,
> > it first surfaced weeks ago, but I had zero time to look into it.
> >
> > Anyway, I have a three drive Smoke Signal Broadcasting disk system,
> > in which one drive, 2 (last one on 0,1,2 chain), has this nasty whine
> > when
> > powered on. The other two drives work and sound fine.
> >
> > The faulty one's driver motor never stops when powered on whereas the
> > other two do.
>
> Sounds like the motor control board is faulty.

I'll find out when swap the good board with the one on the bad drive.

>
> > The others must have the last one due to the terminator
> > which functioned correctly in the chain. I have managed to pull the
> bad
> > drive and managed to get the two working ones to work with terminator
> > resister moved to drive 1.
>
> The terminator should be on whatever drive is last in the chain (the
> end of the ribbon cable).

Yes.

>
> > I put 2's (bad drive) large electronics board
> > onto 1's drive mechanism and it works fine. That leaves 2's drive
> > mechanism
> > as being bad; either the small circuit board or the drive motor.
> > Also, when 2 is selected the red LED does light up, but no diskette
> can
> > be read.
>
> Motors sometimes burn out, but other faults are relatively uncommon.
> These motors normally have three or four wires; two are the power, and
> the other(s) are the tachometer signal back to the control board; this
> tells the control board how fast the motor is going. The tacho may be
> broken, but a faulty control board is more likely. If one of the other
> drives uses the same motor you could try swapping, which at least would
> tel you whether its the control board or the motor itself.

Yes, that is the plan. The motor has four wires.

>
> The whine is probably because the motor is running far too fast, and
> that is why you can't read a disk. Don't let it run like this too long
> or you'll damage the motor.

Thanks.

Eric

>
> --
> Pete Peter Turnbull
> Network Manager
> University of York
Received on Wed Jun 11 2003 - 07:31:00 BST