79:04 error on Designjet Z6100 when idle.

[MBT]

I've been working on a Designjet Z6100 that will boot up just fine, print fine, but will randomly get 79:04 errors when just sitting idle. It's not frequent, they can go a few days, then come in one morning and 79:04 on the screen. I've done an EEROM reset and updated the firmware. On the last visit I cleaned all the print head contacts and we told them to replace the expired printheads and cartridges if it comes back. They did that but it's still doing it.
The one time I was able to see the error, the secondary code for the 79:04 was 0XBABE000B Severity: Error, Priority: 3000
The next step I can think of is to perform a disk wipe and reload the firmware.
If that doesn't work, what would be the next step, Hard drive, ram, formatter, electronics module, carriage, or something else?
Thanks.

[Kiran Otter]

79:04 errors are difficult to narrow down. I would run the diagnostics on each subsystem and see if anything fails.

I have a Z3200 that would give a 79:04 when you were loading the paper. Turned out the line sensor's blue LED was out. I found this by running the carriage assembly diags.

Make sure none of the ribbon cables that run under the electronics module have been mangled while putting the cover back on. There's only a piece of tape that usually dries out to hold the cable up out of the way. Reseat every cable on each end, including the front panel.

It could be the formatter or hard disk. But it could be a lot of other things too. Run all of the diags and hopefully something will pop up.

Kiran