Questions - Universe/68, HP-9134A,VT420 composite video

Steve Robertson steerex at
Sun Apr 17 15:36:45 CDT 2005

> - HP 9134A: The unit is appears on the HPIB bus but
> doesn't identify itself correctly. From the HP64000
> side I get a 'NO DISC' error when I try to format it.
> I am trying to determine whether the light on the
> front of the ST506 inside should be on or not once the
> drive comes up to speed or whether it only comes on
> when that HBIB address is being accessed. Any hints ?

Sounds like the device is responding to the "Parallel Poll" so the
controller recognizes there is a device at that address. This is an
iindication that the disk's HPIB interface is working correctly.
Apparently the disk is not.

When the disk is powered up, it should go through it's initialization
routine. During this phase, the indicator LED on the front panel should
blink at about 2 CPS. After 5 or 10 seconds, the disk will complete it's
initialization and the LED's will change state. An amber LED indicates a
disk failure, a steady green LED indicates that the disk / interface is

The green LED will blink when the device is busy. For short duration
events, (IE write / read) this will be momentary. For longer events,
like formatting a disk, the green LED will blink until the operation is
complete. Low level formatting is strictly a function of the HP9134. The
controller just sends the "format" command and the HPIB controller (in
the disk) does the rest.

It's possible using a HPIB bus analyzer to read the ERROR codes directly
from the interface. I doubt the 64000 has extended diagnostics that will
display the exact failure mode.

I have had problems wit those particular drives before. I wouldn't be
surprised if the disk is toast :-(

NOTE: Although the HPIB spec allows devices to be addressed in the range
0 - 15, I have found that the 91XX disks don't work above ADDRESS = 7.
Check the address switches.

See ya, SteveRob

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