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HP85

HP85


This is our HP85. A BASIC computer and instrument controller introduced on the market in 1979. It has an internal printer and a tape drive that uses DC100 tapes.

HP85 with case
Our unit has been used at Royal Institute of Technology (KTH) in Stockholm. It has been in for service (in the USA) as late as 1996 where it was found that the tape drive was not working. The unit comes with a very sturdy carrying case.


The machine has serial number 2204A55033. The to leading digits indicate  that it is produced in 1982.

Serial number

The sticker below tells that it has been in for service at TSA in August 1996. Maybe that is the reason for the unit being so clean inside? There is almost no dust inside the unit. Not even on the high voltage parts! The printer belt looks brand new and the capstan seem be repaired. Probably by using shrink tube.

HP85 inside






The CRT has no burn-in at all and looks almost brand new.

The unit also came with a PROGRAM ROM drawer which included five ROMs.
HP85 ROM


The ROMs are INPUT/OUTPUT, MASS STORAGE, ADVANCED PRGM, MATRIX and PLOTTER/PRINTER.









Finally running the machine

HP85 running


Another HP85

We got an email from Sten Boje Dahlman who had a HP85B that needed to go when there was a cleaning in the basement. Sten used it for measurements on pressure vessels when working as an independent consultant. The HP85 was connected to strain gauge load cells through an 82941A BCD Interface and a small BASIC program was run on the machine to collect the data.

HP85B
The machine was in very good shape when received but needed some cleaning and a capstan rebuild. The old polymer on the capstan had converted into a liquid goo and was removed mechanically and with help of some aceton. Then a small piece of shrink tubing was shrunk on the cleaned pulley. To secure it we glued it in place with some super glue and trimmed it with a knife.

This is a HP85B which is a modernized version of the HP85. It has 64 k RAM and then also the mass storage option built in to the firmware.


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