HP85A Stuff

I spent a little more time on this guy and have finally gotten the tape drive to work--sorta. The rubbery roller in the center to the left of the head is seriously corroded away (as if some anti-rubber solvent or high heat came in contact with it) which makes it not work too well. Cleaning it up as best I could, and then doing multiple retries, getting frequent READ or SEARCH errors, have allowed me to store and retrieve some simple programs. I guess I'll be opening this up and trying to replace that. Now, questions: I have a ROM Drawer filled with six option ROMS like Assembler, Input/Output, Mass Storage, etc. First, how do I implement the physical link to the I/O devices? There are zero physical port connections on this box...(?) Second, how do I access the ROM code from the BASIC prompt? I'm sure there's a lot of tricky stuff involved, making the manuals indispensible, but since I don't have them, any quick tips would be appreciated. -- mor(a)crl.com http://www.crl.com/~mor/