Electronic Alarms and Home Security Devices - "Check 81" Issue with Ademco 4219 Wired Zone Expander

I have an Ademco Vista 4120XM with a 4219 Wired Zone Expander. All zones appear to be working properly, but I just started getting a "Check 81" message (accompanied by rapid tones at the console), which according to the manual "...indicates a problem with a wired zone expansion unit in your system..."

I've checked all the connections and they appear to be fine. I've also disconnected the power and then reconnected -- after which it will seem to be working properly for awhile -- but then a few hours later, I'll get the "Check 81" message again.

The unit is at least 13 years old (it was in the house when we bought it).

Any thoughts on how to fix this issue would be appreciated. Do I just need to install a new 4219?

Check and see if the jumper for the tamper switch is in place, or if it's in the external cabinet, that the cover is on securely so the the cover magnet engages the reed switch.

Yes, the tamper is disabled -- as it has always been. Any other thoughts?

The only thing left after that is component failure. Either the expander board is failing, or the motherboard is failing. This is a 15-16 year old piece of electronics, at it's newest, and it's powered up 24-7. The second law of thermodynamics hasn't changed.

This is assuming that no attempt at programming changes have been made.

Thanks. If I just get a new 4219 and install it, should I just be able to move all the wires to the same place on the new board? Or, will I need to redo any programming?

Naw, it's basically a dumb device. Copy the dipswitch settings and the case jumper, and if all else is ok, it should work.