14" disc media problem?

From: Jay West <west_at_tseinc.com>
Date: Mon Apr 10 21:09:16 2000

I'm hoping someone can tell me something I'm missing here, cause I just
can't believe what I'm seeing....

HP7900A disc drive, using the standard media for it. The media for this
drive is virtually identical to an RK05 cartridge. I have 4 pieces of media.
I pulled a cartridge from the stack and tried to spin up the drive. Blowers
come on, but when you hit the load switch the spindle just sits there. After
three days of checking all the sensors, tracing the wires, pouring over the
schematics, still no go.

So finally on a whim (yeah, it's the first thing I should have tried) I
pulled out the cartridge, popped the cover on the drive and defeated all the
sensors. The drive spindle motor started like a champ. Put the cartridge
back in - no spindle motor. However, I noticed that when the cartridge is
in, the relay that gives AC to the spindle motor does engage correctly, but
no spindle movement. So to make a long story short, I tried the other three
pieces of media I have. I put in each piece of media at least 20 times -
every time the spindle starts up fine. But, put in that first piece of
media, the relay engages, but the spindle sits still.

What gives here? What on earth could be wrong with a media cartridge that
would cause the spindle not to move? I tried lifting up the platter slightly
and turning it, it seems to turn just as freely in the "bad" cartridge as in
the other three. I'm just really confused - is there something I'm missing
here???

Dazed and confused....

Jay West
Received on Mon Apr 10 2000 - 21:09:16 BST