15 Aug
2015
15 Aug
'15
6:37 p.m.
On 8/15/2015 11:59 AM, Chuck Guzis wrote:
I went and stared at some of my 8" drives for a
bit this morning.
It occurs to me that if your top guide frame is laterally "warped", the
centering of the hub clamp assembly won't work.
Agreed. But the darn thing is cast, with lots of fillets for support.
I wonder how it would ever get warped, short of something REALLY heavy
being dropped on it, or it itself being dropped from a considerable
height - and there is no evidence of that.
However, I thought I would test an SA 801 (jumpered as an SA 800) on the
thing, so I could test the controller at double density. When I did
that, something died (smelled electronically burn-y) after a few seconds
of OK operation. Not sure if it was one of the tantalums or the stepper
or something else, though. Anyway, I now have a drive that I can pull
the clamp arm out of (the top guide frame, as you say) and try in the
failing drive, to see if I can nail it down to that part of the spindle,
just out of curiosity.
If you've got a wiggler gauge handy, you may want to see what the
deviation is when the hub clamp mates with the spindle hub assembly.
While you're at it, you may want to check the spindle hub itself to see
if it's not out-of-round.
Don't have a wiggler gauge, or anything to use it with.
There's a patent 3,898,814 on the Shugart clamping system that many
manufacturers licensed. Perhaps it can shed some light.
--Chuck