The 9825B replaced the 9825A in 1980. It came standard with 23K RAM and internally integrated ROMs for Strings, Advanced Programming, Plotters, General I/O and Extended I/O. The 9825T was also introduced in 1980. It came standard with 62K RAM, all of the ROMs of the 9825B, plus a built-in Systems Programming ROM.

The 9825 was a very successful product for HP. In October of 1980, the company built the 25,000th 9825. 17,000 had been built in Loveland/Fort Collins, and the other 8,000 units had been manufactured in Boeblingen, Germany.

The 9825 was obsoleted in May of 1985.

Click here for a detailed look at the 9825 and its many innovations.

Click here for great information on 9825 tapes drives and how to get them working. Larry Atherton (that great refurbisher of HP-85 computers and tape drives) will soon be offering rebuilt and fully-functioning 9825s.

For more information on the 9825, please visit: www.bohemiae.com.

Ansgar Kuekes has created an amazing utility for allowing a modern PC to emulate disc drives for the 9825. To run "hpdrive", you only need a GPIB card for your PC and a 98034 HP-IB interface: HPDrive. Using Ansgar's "HPDir" utility, you can use your PC to perform disc operations on the old software (copy discs, transfer files, etc): HPDir

For a detailed tutorial on restoring 9825 tape drives and tapes, be sure to visit the hp9845.net site. Here.

Collector’s Notes:

A little over half of the 9825s that we see at the museum will power up and provide a working display. These machines will correctly perform calculations, run programs and address external disc drives and printers. The most common problem of the non-working machines is no display on power up. If you have such a machine, you can confirm that the internal logic of the computer is working by typing "beep" (without the quotation marks) and pressing the EXECUTE key. The machine will beep if it is working.

Almost all 9825s are afflicted by non-functioning tape drives. This is usually due to a gooey capstan wheel. Another common problem occurs with the built-in thermal printer. The paper advance mechanism fails on some units, providing output that looks like a series of short horizontal lines.

The power supply voltage test points are a little tricky to get to, but this is manageable (see the service manual). Be sure to check your voltages if you suspect any problems that may be power related. If your 9825 occasionally displays strange characters on power up, then it is likely that your system ROM module is defective. This is the large module that plugs in to the right side of the machine.