HP250

HP 250 model 45252A (option 004,012)

Condition

Fix the mold spots. This is a known problem and has been discussed on the cctech mailing list. E.g. here and here.

Find a way to transfer software from the outside world. HP Museum has a number of disk images with software for the 250/260. But you need a 260 to copy them from 3,5" to 8". I see following solutions:
- Connect an 8" drive to a PC (see [1]), convert the 3,5" teledisk images found on hpmuseum to 8" using the utilities found at [2] and write them to a real 8" disk.
- Find a HPIB PC card suitable for HPDrive, convert the 3,5" teledisk images found on hpmuseum to 8" raw image and let the PC serve as a drive for the 250. This is better solution as it allows to boot the 250 should the 8" drive ever fail.

The 3,5" floppy cannot be used. The media test program included on the B.7.00 system disk shows an X2,3,0 device, but says it is unsupported. Also the hpmuseum.net claims a 250 cannot use 3,5" disks.

The ROM can only boot from 8" flex disc (see page 351/11 of the HP 250 Service Handbook found on HP Museum). Setting the thumbwheel switch on the processor board to 8. => it ran a memory test. So it must have the old ROMs for which there is no setting to boot anything else than the "floppy" or a 7910 hard disk (which I don't have)

The HP Drive projects seems to be a way to exchange data between the 250 and the outside world. It uses a PC with HPIB card to act as a mass storage device for old HP computers such as the 250. The Ima2hpi utility on the same site allows to convert teledisk images (such as found on hpmuseum.net) to raw images usable by hpdrive. Also HPDir allows to access the files from the image or a real HP mass storage device. (however, connecting the internal 8" drive of the 250 to a PC may be non-trivial as the HPIB controller of the drive is in the 250 main frame).