Computerarium

Donated 4/2018.
Non-functional when received - no monitor, no power supply.

Includes Eventide WMAZ-4 RAM board in undocumented WMAZ-4(3) configuration, corresponding to 3 HP 128K memory boards. Supplemental ROMs from Structured Software Systems with PUP+, MMS and CMD are installed.

The Option 100 power supply was removed from 9845T S/N 1838A06653 and (re-?)installed in this machine. Initial power up resulted in a single beep, fan noise and power LED lighting on processor but no video output.

Voltage readings from the power supply test points were as follows:

• C17: 165.9V, C18: 165.7V
• +17: 17.97V, +13: 13.04V, -17: -18.06V
• +18: 19.02V, +12: 2.18V, +7: 6.98V, +5: 5.14V, -12: -12.14V, -18: -19.06V

Other than the +12 value, everything is within specification (+/-17V and 18V call for a +/-1V variation, but I'm not worried about a few hundredths of a volt). This is pretty amazing performance from a 40ish year-old power supply.

Now on to the +12V problem …