HP 5347A Fails HP-IB Test

[mbielman]

Hello. I repaired an HP 5347A (20GHz freq counter) and this unit did not have the HP-IB interface option. I found one, installed it, and it fails the HP-IB power on self test. Installed a known good interface card and still fails. Continuity from the motherboard is good and the 5V supplies are fine. There are no option jumpers anywhere that I can find and the manuals make no mention of this... just install the card and that's it.

Wondering if I have a firmware rev issue or some such thing.

Anyone have experience with this?

Appreciate the help.

Thanks.

Mark B

[jfphp]

You have probably to enable the option in the configuration EEPROM on the CPU or, if no EEPROM, to change the firmware in the EPROMs

[mbielman]

There is no EEPROM and no config menu or settings to alter. This is what I do know:

The EPROM on the CPU board has the proper HP part# and the service manual has no comments regarding versions so suspect it is the right code.
The unit has a "IB SENSE" line that gets pulled low when the card is installed so the system knows if it has HP-IB or not.
Power supplies, RESET signal and interconnect continuity are all good, and it is a known-good interface card.

The data and control lines are connected directly to the CPU (6803).

A bit stumped.

Mark

[mbielman]

FIXED IT! Someone had replaced one of the connectors on the MB to the CPU board and apparently destroyed two of the connections that control the HP-IB interface. (!)
Added two jumper wires and it works. Another unit saved!!!

Mark

[Tony_G]

Nice - Congrats.

TonyG