Problems with HP 1/8 Autoloader


The problems with the HP 1/8 Autoloader were:

1.  Backlit LCD display flickers.

2.  The HP 1/8 Autoloader randomly locks up the SCSI buss during backups.  The error presented by the backup software is (Bru Server Mac OS X):  “Short SCSI return in INQUIRY”.

The autoloader then needed to be powered off, and on again and the host computer restarted, for it to work again.  Sometimes it is necessary to repeat this several times.

This problem started at the same time the display problem.

The computer and SCSI card had been checked, no problems found.   The computer/SCSI/backup software has not been changed, and worked well for over 12 months.

Tape drive firmware has been updated, but did not solve the problem.

After about an hour on the HP tech support line, I finally got the contact details for the Australian repairer for HP tape drives and autoloaders (they couldn’t help me more than that!),

I sent an email to cxp, and one of their tech’s replied saying it’s probably a faulty PSU..  I bought the drive back to the workshop, took it apart, and checked the voltages from the PSU.  12V was OK, 5V line was only reading 4.7V..  Got out my trusty oscilloscope and checked for AC ripple, 5V line had about 200mV ripple..

Took out the power supply, and first thing I noticed was two bulging capacitors (1500uF 10V) on the output stage!   Replaced both with the closest values I had, and it’s all good!

Unfortunately I was so hell bent on fixing it, that I didn’t take photos..   Photos of the oscilloscope would have been cool, you could see how “fuzzy” the signal on the 5 volt line was…