micropolis 1355

From: Kevin McQuiggin <mcquiggi_at_sfu.ca>
Date: Fri Jan 15 23:01:30 1999

Hi Tony:

I've been talking up the _other_ common reason for the spindown problem for
the last year at least. This is the spindle brake problem, it fails to
retract fully, causing the spindle to rub and not get up to speed.

I've had two RD53s with this problem, moving the brake solenoid back a bit
fixed it in both cases.


At 07:25 PM 99/01/15 +0000, you wrote:
>> > The other cure is to open up the HDA and free the head manually. If you
>> > do this in reasonably clean conditions (not necessarily a proper clean
>> > room) then you should be OK.
>> I've done that, but now it spins up, and after appr. 1 minute spins down
>> again and spins up, ....
>Hmm... I've never seen one do that. The microcontroller is obviously
>finding _something_ wrong, but no idea what (yet).
>The Micropolis 1200 8" drives had a very useful facility of a diagnostic
>connector on the control board. It brought out a number of useful signals
>and also an 8-bit port from the main microcontroller. Add a latch and 8
>LEDs and the thing would display a diagnostic code if it shut down. There
>was a table of these in the manual so you could work out _very easily_
>what the problem was.
>I don't know if the 1300 series has anything similar. I don't have the
>service manual (I am looking for it, BTW).
>Common problems are that the motor speed hasn't stabilised in time (or
>the drive doesn't think it has), the servo can't find the home track (or
>it's not locking at all), or the motor is drawing too much current.
>Finding out what's going on isn't that hard with a schematic + scope
>(looking at the servo drive waveform will tell you if it's locking, etc).
>Are there any unusual noises from the HDA (like an actuator buzzing
>because it's not locking on track). Does the head sound as though it's
>moving at all?
>> Dead ?
>> thanks,
>> emanuel

Kevin McQuiggin VE7ZD
Received on Fri Jan 15 1999 - 23:01:30 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:32:06 BST