13-06-2024, 06:24 PM
(This post was last modified: 14-06-2024, 08:26 AM by Colin Morgan.)
As those who have dismantled one of these early spade key PLC switches will know, the pressure that holds the ignition contacts together deep inside is produced using a small spring below the metal 'barrel' that the key turns. The pressure from this spring is resisted at the top by the 'keyhole' metal around where the spade key is inserted. If this breaks away completely, the 'barrel' can pop out and the spring falls loose inside the switch. Whilst the barrel can still be pushed back in place, there is then no pressure to make the electrical contact between the brass pads within the switch. Adding an external washer is a good workable solution as the 'barrel' is then held in place against the pressure of the spring and the key can be inserted as before. It may be necessary to dismantle the switch to put the spring back in place. This must be done with care as the whole thing can fly apart driven a second, larger more powerful spring inside. However, if everything is kept under control, and the orientation of the top maintained, it can be a relatively simple 'operation'. So long as this spring is in place, and everything is clean inside, there shouldn't be any need to press in the key hard to achieve a good contact.
On my car, where a screwdriver has been used for years to turn on the ignition - by others and me, there is very little metal left holding the ignition switch together - so I am very gentle with it in the hope of prolonging its useful life. Unsurprisingly, old switches in serviceable condition appear to be rare.
On my car, where a screwdriver has been used for years to turn on the ignition - by others and me, there is very little metal left holding the ignition switch together - so I am very gentle with it in the hope of prolonging its useful life. Unsurprisingly, old switches in serviceable condition appear to be rare.