29 Sep
2011
29 Sep
'11
5:38 p.m.
On Thursday (09/29/2011 at 04:29PM -0400), Ethan Dicks wrote:
On Thu, Sep 29, 2011 at 4:16 PM, Dave McGuire
<mcguire at neurotica.com> wrote:
Ya... good idea except, I can measure nice clean tach pulses on the
board after the op-amp stage that the photo transistor in the interrupter
drives. So, I think I'm getting good tach signal from the interrupter.
I've completely cleaned the unit so the dust bunnies have been long since
exorcised.
--
Chris Elmquist
?I believe there's an optical shaft encoder
on the spindle motor of the
TU58. ?I'd check to see that the disk (which is paper-thin sheet metal) and
the opto interruptor aren't clogged up with dust bunnies, then test the opto
interruptor itself.
I can't remember the symptoms when it doesn't work, but it's a good
thing to check. If the device was powered on for thousands and
thousands of hours, the IR diode could be a bit dim - I've seen that
with 15+ year old optical interrupters before (and successfully
repaired the gear with a new interrupter).