HP 86: Strange Error

[Paul Berger (Canada)]

I have never seen a service manual for 86A but as far as running diagnostics you can use the 86B manual found on the MoHPC manual collection. On hpmuseum.net there is also a manual "86A-B_Self-PacedLearningGuide" that is a service training course and has a little bit on running diagnostics. The diagnostic ROM is a take over ROM and it will boot up to a prompt for a single character command for the test you want to run, and if you do not enter anything after a few minutes it continues on to BASIC. The ROM test is "D" for the system ROMs and M for expansion ROMs. The 86A apparently has the Mass Storage and Printer ROMs built in as well as the BASIC ROMs.