HP 86: Strange Error

[rprosperi]

(11-19-2017 12:07 AM)Michael Fehlhammer Wrote:  My newly acquired HP 86A displays a strange warning immediately after power on:
Warning 27: 85 ROM disabled.

Michael - The HP-87 "Operating and BASIC Programming Manual" (I don't have '86 docs, but as you know they are quite similar) includes Error 27 (a warning) in the Error Message Appendix with this Error Condition note:

"An HP-83/85 ROM is installed in the ROM drawer. The ROM is ignored by the system if no ROM with the same ROM number is present."

The wording of the final sentence is a bit strange to me, as I'm not sure how some other ROM could have the same ROM number as an 83/85 system ROM; perhaps this could happen if some signal lines on a board are damaged?

Any chance there are additional ROMs installed internally?

Assuming it's a false positive, I'd say it's likely safe to ignore as far as how it will affect your use of the machine, since it is disabled. The actual cause of the condition may be reason for concern though as something is being detected incorrectly.