Hi,
I have updated my web page with further details on the PRM-85 module:
http://www.vintagecomputers.freeserve.co.uk/hp85/prm85.htm
This is a clone of the Series 80 (HP-85/87) Programmable ROM module, which allows EPROM copies of ROMs to be used. This is mainly to allow access to the Assembler and Extended Mass Storage ROMs, and also for the HP-85 Service ROM.
Please take a look, and if interested please e-mail me and I will add your name to the waiting list (currently 5 names long).
I (and others) would be interested if anyone has a Service ROM for either an HP-86 or HP-87. Please get in touch if you would like to help make a copy for use as an EPROM.
Regards,
John