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Acquisition, and a Dangerous Fault

Checkout of new machine, dangerous fault identified and rectified

This machine was acquired from a thoughtful individal who had rescued it from his workplace shortly after it was superseded. He had recognised that it was something special and acquired it, rather than see it discarded. He kept it in clean dry storage for over thirty years before deciding to pass it on for continuing preservation.

General condition was very good, consistient with its excellent storage history. It was briefly demonstrated when acquired but it was not powered up again until it had been fully inspected and cleaned. Powerup of long-unused equipment can be hazardous to operator if wiring and/or insulation has deteriorated, and hazardous to the equipment if components (particularly electrolytic capacitors) have degraded.

Main Power Inlet Fault

Good practice was well justified in this case as a nasty and very dangerous fault was uncovered. The mains power wiring from the input socket to the power switch was overheated and burned, with live wires at mains potential easily able to have contacted the metal case. Fortunately, the case was earthed at the time of original manufacture and this had remained sound.

The source of the overheating appeared to be within the actual wiring, perhaps a dry joint at the mains switch or a high resistance contact within the power switch. The power switch was able to be repaired/restored, the damaged wiring was replaced and an IEC socket was substituted for the original socket, allowing a modern mains lead to be used.

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