80 Series Newbie

[Paul Berger (Canada)]

(08-14-2015 01:49 AM)Dave Frederickson Wrote:  HP-85B Update:

The tape drive is back after being refurbished by Larry Atherton at LA Tech Renewal. Got some orange printer belts, too. The unit had been dropped and I've straightened the back panel and repaired the minor case damage. Keyboard has been disassembled, cleaned, and DeOxified. GPIB card installed in vintage PC ready for HPDrive. Also joined the HP Series 80 group on Yahoo.

Two questions:
1. Can I burn the Service ROM to a 2764 and plug it into the empty socket on the Logic Board? Just a rhetorical question 'cause I'll try it anyway after verifying the pinouts.
2. Does anyone have the I/O Exerciser Tape files with EDTEST to test the upper 32K of RAM?

Dave

1. No the ROMs used in the 85 use multiple supply voltages and are designed to work directly off of the Capricorn bus, which has 8 lines carrying both address and data, addresses are clocked out as two sequential bytes that devices on the bus are obliged to latch and for memory devices they must also be prepared to increment that address without a new address being clocked out when reading sequential bytes, up to 8 bytes may be moved in this manner, which conveniently happens to be exactly the size of a full precision floating point number.

Sorry can't help with 2 diag ROM is the best way to go for testing memory, that is one of the things that spurred me on to creating my own ROM card.