PDP11/23+ frustration

[Joe R.]

At 09:22 PM 6/17/05 +0200, you wrote:
>Hi,
>
>
>> it is a REALLY REALLY REALLY bad idea to just power old removable disk
>> drives up to see if they will 'just work'
>> as you discovered, THEY DON'T, and destroy themselves in the process
>Yes.... :-(
>
>> look at the messages from Tom Jennings about all the trouble he had
>> getting his going over the past few months
>Hmpf, I forgot. Yes, he had some trouble with his Nova...
>
>
> > 1) you now have a piece of junk
>> that is most likely unrepairable unless you are VERY lucky and can
>> clean the heads
>Are there any tricks beyond Isopropanol?

   Yes, use Texwipes or other LINT-FREE wipes!!! One piece of lint and
you're loooking at another head crash. You also need to perform this in a
CLEAN room.  Note I didn't say "cleanroom", just an ordinary room that is
very clean.

  IMO you'll be very lucky if your drive head(s) and disk platter(s) aren't
ruined.  These old drives are VERY finicky, that's why I passed up the
drives that I was offered with my PDP-8. I used to work in Field Service
for Burroughs Corp and we were constantly having to repair these type
drives even when they were used under ideal conditions.


>
>> 2) you've destroyed the disc pack (which may be
>> difficult to repace) and 
>I have a few others.... Perhaps the drive has crashed before. Because 
>one of the packs is open and the disk has these nice concentric stripes....

   Was that the pack that was in it when it made the noise? NEVER put any
pack in a drive unless they both in perfect condition you'll probably
damage both of them.

>
>Should I take the drive to the scrapyard immediately?

     IMO yes. But I hate those monster drives! But to be fair I'll tell you
that it can almost certainly be fixed. Even though it's an odd brand unit,
the drive and heads are almost certainly standard brand parts so it
shouldn't be TOO hard to find replacements. But an alignment disk will cost
about $300 and you'll need to service manual for the drive in order to
realign it after replacing the head. I don't know what heads cost these
days but they were about $100 each back in the mid 70s.

   Joe




>
>
>Regards,
>Philipp
>