Summary Restored and fully functional
This machine had been kept in well protected storage and was complete, in good condition. It was stripped down and cleaned, with special attenttion to the electrical connectors. The power supply was tested with dummy loads and voltages were adjusted. It was then powered up and was fully functional.
The AL-1000 was acquired from a retired surveyor. He'd acquired it in the early 1970s in an office merger and he recalled that it was rather obsolete at that time and that his office did not use it very much, preferring other calculators. It has been stored for nearly forty years.
It was in compete and undamaged condition. It was dismantled and all circuit boards were removed. The case was washed and the substantial metal chassis was cleaned, the circuit boards were cleaned, the edge connectors were cleaned with pencil eraser and DeOxit. Several connector fingers had marked green corrosion and the corresponding socket locations were cleaned. The boards all appeared undamaged with no sign of overheating.
The mains wiring and earthing was carefully inspected and found to be in good condition. The mains cable was in satisfactory condition, the old style plug was replaced with a modern version.
The power supply board was traced and a circuit was generated. Connectors were added to the low and high voltage sides for easy connection of dummy loads and meters. The low voltages were out of adjustment but were easily re-adjusted. The high voltages were all high and are not adjustable except by adjusting components, this was done and the result remained on the high side but was accepted.
First power-up was successful. The nixies take some time to light and the last one or two may take up to a minute. This is probably related to the high voltages being off-spec and the ageing of components in the drivers. Since the machine otherwise works well, investigation is not a priority at present.
The AL-1000 is fully operational. It is powered up occasionally to keep the power supply filters well-formed and there have been no failures since first restoration.