Hp9133 hardware problem

[Maximilian Hohmann]

Hello,

while trying for a fellow forum member to locate a file belonging to the Lattice-C installation on my Hp150, I found out that after 15+ years of storage nothing seems to work any more.

After digging out the Hp150 and it's accessories under heaps of other stuff in my garage (or barn, whatever one wants to call it) and plugging everything together, this is all I get:



The video/screen of the computer does not work and the disk drive displays the "Fault" LED. I disassembled and reassembled both the computer and the Hp9133H drive, re-set all modules and connectors and cleaned what I could clean. No change. The drive passes some of the onboard self-tests described in the service manual but fails others, among them the crucial disk-write and disk-read checksum tests. I suspect, based on experiences with other old hard disks, that the drive arm is blocked or stuck.

Before I open the winchester drive itself to look for for a possible fix, I would appreciate any idea or hint what else I could try without (possibly) destroying the unit and all the software it contains (some of which was issued to Hp employees only and will be difficult to impossible to retrieve elsewhere). Right now I have no other computer with an HP-IB interface which I could use to talk to the unit. However I have an HP-71B with a HP-IL to HP-IB interface but no idea if it could be used to retrieve anyting from that MS-DOS formatted hard drive?

Regards
Max

[Dave Frederickson]

Hi Max,

Disc drives of that era were susceptible to a problem known as "stiction" where the R/W head sticks to the disc's surface and prevents it from spinning up. Opening a drive is risky as even the tiniest dust particles getting inside the drive enclosure could cause the head to crash.

The Data Acq ROM for the 71 contains some programs for reading DOS discs. Also, with a GP-IB card the drive can be accessed with HPDrive.

If you get the drive working be prepared to backup the data ASAP. Also, you might consider a professional data recovery service.

Dave

[Maximilian Hohmann]

Hi Dave,

thanks for the quick reply! I think it must be another fault than the sticking head, because the drive can be heard turning and making other sounds more or less typical for hard disks. It also manages to pass the "Winchester speed" and "Winchester seek" self tests. (But not "Winchester write verify" and "Winch. verify" - passing the "write" test would not be important as we only need to read some files right now).

The Data Acq ROM, according to a manual I found online, can only access the HP 9114 Disc Drive (which is floppy disc only other than the 9133 which has one floppy and one hard disk). Anyway, I think that it will be near impossible to find.

Right now I am bidding on GPIB/IEEE488-cards on eBay and if successful will try accessing the disk through one of these (myself I turned to Macintosh right after the Hp150 but our son has a PC).

Regards
Max

[Sylvain Cote]

The service manual is available HERE.
For sure you will have to replace the 2 x N batteries.
Chapter 6 guide you through the multiple self-tests the unit has.
Good luck!
Sylvain

[jebem]

(03-28-2016 02:12 PM)Maximilian Hohmann Wrote:  The video/screen of the computer does not work and the disk drive displays the "Fault" LED.

The picture shows that the CRT HV is ok, but the cathode voltages are wrong or the driving signals are absent.
Either way, the first thing to check is the power supply voltages for the correct values (within 5%).

EDIT:
1. Please make sure you have someone qualified to handle this kind of equipment that operates with CRT HV (High Voltage) inside!!!

2. According to the service manual, the power supply voltages to check that I referred above, are:
+5VDC
+12VDC
-12VDC