Dec RL01 drive problem

From: William King <wrking_at_tsoft.com>
Date: Thu May 6 09:57:36 1999

> -----Original Message-----
> From: Tony Duell [mailto:ard_at_p850ug1.demon.co.uk]
> Sent: Wednesday, May 05, 1999 12:01 PM
> To: classiccmp_at_u.washington.edu
> Subject: Re: Dec RL01 drive problem
>
> The speed behaviour might be correct. The speed of the spindle motor in
> an RL01 is regulated, and the feedback is taken from the sector
> transducer. Without a pack in place, there will be no sector pulses, so
> no feedback, so the logic will think the motor is stopped and will try to
> speed it up.
>
> If the heads are attempting to load, then the drive thinks the pack is
> spinning at the right speed.

The spindle motor speed being regulated explains why things slow down. They
just slow
a little too much. The motor can't be doing any more than 120 RPM when the
heads attempt
to load.

>
> My first thought is that for some reason the heads are not detecting the
> servo pattern on the disk, so they can't lock to it. I assume you're
> using a known-good RL01 pack -- and not just some pack that looks right,
> an RL02 pack, or one that has been bulk-erased.

Well the answer is yes and no. I just purchased two DEC brand RL01 packs
from
Keyways. They came "as-is" since Mitch didn't have a drive to test them on.
Both packs
behave the same.

>
> Are the heads clean and correctly connected to the R/W module (central
> module in the drive chassis)?

Heads look clean and all connectors within the drive look firmly seated. The
head assembly
moves freely.

>
> If yes to both of those, then we need to troubleshoot the servo logic. I
> have the printset and tech manual here. You'll need a 'scope, though.

I'm sure I can find one in a couple of days. Is there anything else that
should be checked
first (power supply)?

>
> -tony
>
>
Received on Thu May 06 1999 - 09:57:36 BST