The resurrection of a VAX-8250


The VAX-8250 here was once located at a large chemical company and was used in a CAD/CAM-application. When I worked as a consultant for this company I asked the people at the computer center to inform me as soon as the machine would be finally powered down.

Two years later they called and I rescued the machine from scrap. Unfortunately I had no room for the machine in my flat so it was stored in a garage. About one year later I moved to a different location and had the necessary room to put the machine in the house.


Some pictures of the event

  • The dismantled VAX-8250 (on the right) and some other equipment (half of a PYRAMID MIServer, a Siemens RM600, a PYRAMID disk array, etc.). The most difficult task was to bring the CPU, a TU81+ tape drive and a dual RA82 up nine steps to the house.
  • Everything has arrived in the house eventually.
  • The first step: The machine is in place.
  • Removing the transport locks from the RA82 drives.
  • The controller section of the upper RA82 drive.
  • Here you can see me replacing the faulty power controller of the CPU cabinet.


The state of the machine at the first power on was as follows:

  • The CPU passed its selftests except the RX50 console floppy test - replacing the RX50 with a spare drive corrected this.
  • The TU81+ tape drive did nothing at all which was due to a faulty power supply. To be honest, I did not trace the error down to repair the switching power supply since I had a spare one in my garage, too, so it was simply replaced.
  • The tape drive did not pass its selftest with error 66. Fortunately several years ago I stumbled over a severely damaged TU81+ on a scrap yard and ripped off all boards. After replacing the sandwich controller board, the tape was up and running fine.
  • The two RA82 disk drives had problems too: The lower one ended with the ERROR light lit, when powered on, while the upper one did not spin up when depressing the RUN switch. With the drive cover open and careful listening one could hear that the motor tried to spin up the disk pack but could not turn and was shut off by the overload protection logic in the drive logic. After removal of the motor it showed that the drive belt was stuck to the motor shaft. Fortunately I have some spare (originally packaged) drive belts for RA drives. :-) After replacing the drive belt the drive came up fine. Since the motor made horrible noise, I swapped it with the motor from the lower RA82 drive, which still is not in operational status.


In the following week the machine was slightly enhanced by

  • adding another 16MB BI-bus memory board and two additional 4MB BI-bus memory boards giving a total of 40MB (one 16MB board was already installed in the machine) and
  • adding a spare KA825 CPU card and configuring it as attached CPU, so the VAX-8250 was turned successfully into a VAX-8350. (Does anyone have a spare nameplate for the machine? :-) )