VT180 is a CP/M based computer introduced by Digital Equipment Corporation (DEC) in 1982. It’s essentially a VT100 terminal with the VT18X option added. The VT18X contains a 2 MHz Z80 processor, 64K RAM, a floppy disk controller and an extra serial port controller.
This VT180 belongs to Dalby Datormuseum, and was restored to working order during spring 2020.
The machine was opened, cleaned and inspected for any obvious faults.
The power supply looked fine, no faulty capacitors and output voltages were according to spec when it was powered on.
No smoke when powering on the machine, but also no horizontal deflection.
A bipolar capacitor (C441) on the video board was replaced, but still no horizontal deflection. C439 (originally 75 uF 6V) was replaced with a 100 uF 63V capacitor (link).
An overheated R481 resistor was also replaced, and finally something happens in the horizontal direction.
Cleaning/deoxidising and resoldering the pins on the video board connector to the deflection coils, and increasing the tension in the springs in all molex connectors was the final step needed to get full picture width on the CRT.
A few RIFA capacitors were replaced in the floppy drive unit and some general cleaning performed before it was powered on.
The diagnostics disk could be read and all tests completed successfully.
CP/M booted successfully as the final test.
The sticker was left on as a reminder to turn it off overnight.