R80/RA81 diagnostic experience? - test-drb@ccmp.vtda.org

8 Mar 2004

I am not sure that removing the brake will help.
I once heard the following rumour:
the brake in combination with the 'heavy' motor
makes sure that the disk platters always rotate
in the same direction, never for a short instance
in the other direction (vibration, power flutter,
whatever reason). Rotation in the opposite direction,
for any short moment, will cause the air on which the
r/w head fly to disappear and result in an immediate
head crash ...

As I said, it is a rumour I once heard a few years ago.
Has anybody heard of this too?

  gd luck with your drive,
- Henk, PA8PDP

...
  -----Original Message-----
 From: Brad Parker [mailto:brad@heeltoe.com]
 Sent: dinsdag 9 maart 2004 2:50
 To: General Discussion: On-Topic and Off-Topic Posts
 Subject: Re: R80/RA81 diagnostic experience? 

 Tony Duell wrote:
>
>IIRC there's a microswitch which detects that the tensioner 
>lever is in the 'tensioned' position, but nothing more. Of
>course the drive does check that the spindle is rotating at
>the right speed when it's spun up.  
 I pulled the HDA - the belt tension switch was fine.

 I found, however, the electric brake was *extremely* tight.  So much
 friction that I doubt very much the motor could spin at all.  
 I removed it (I'll sand down the 'brake pad' later).

 Hoping for a small miracle I fired it back up but still no joy - the
 motor (now free) refused to spin up.

 [a side note: the unit does not seem to reset no power up - 
 it comes up with all lights on until I click the reset manually.  
 sometime tells me this is a symptom]

 I need some prints so I can trace the motor power back to the micro...

 Any have prints for an R80 (or RA80/RB80/RM80).  Or an RA81?  
 I suspect they are similar in terms of motor drive...

 -brad 