HP7900A drive

From: Jay West <jlwest_at_tseinc.com>
Date: Fri Jun 18 16:59:43 1999

I talked to a guy that does 7900A repair today. He said from what I
described that the heads are probably just in need of strong cleaning with a
toothbrush, then touchup with 100% alcohol. As long as the gimbal isn't
bent, all should be well. That takes care of the heads.

Then you wrote...
>I fixed a Plessey RK05-a-like drive years ago using a platter taken from
>a standard RK05 cartridge. If you're lucky (and I was), the fixed platter
>seats on a machined area of the hub/spindle and doesn't need to be
>centred up. Otherwise you have to centre it with a dial gauge before
>clamping up the screws.


He also said the platter scapes make the platter almost, but not quite,
useless; and that I definitely need a new platter. The lower platter on the
7900A does in fact seat on a machined area of the spindle and doesn't need
special centering - "just bolt it on? - just bolt it on". He said I could
use any 14" disk media that was the right thickness. Can't remember if it
was 50 mils or 75 mils. I think it's the same as the RK05. I'll find out the
mils number tonight when I compare my 7900 cartridge with my 7905/6 one. All
I need to do is clamp a metal micrometer on the platter <just kidding
folks!>.

So - does anyone have a broken RK05 type cartridge that they'd part with so
I can steal the platter out of it?

>It's worth trying. Clean the platter as well. It can't do _more_ damage,
>after all...
True, but if there is so much scraped oxide that the badtrack list is 10% of
the platter, why even bother.

I've been quoted anywhere from $50.00 to $250.00 for a media only surface
(no hub, which is all I need). Hopefully someone here can help out?

Thanks in advance!!!

Jay West
Received on Fri Jun 18 1999 - 16:59:43 BST