|The MGA With An Attitude
SINGLE POLE SWITCH Anatomy- ET-131
On 2/5/2016, Mark Wellard in Australia wrote:
"Anatomy of a single pull Lucas switch. In the unlikely event that one of the single pull Lucas switches needs attention, this is what they look like when disassembled. The switch is held together by two crimped sections at the base. Once these are pried open, the Bakelite block can be wobbled out – this one was quite tight".
"There are two copper fingers/contacts on the Bakelite block, insulated from the body by a ring of thick grey paper. There is a brass central contact riveted to the shaft so that when the knob is pulled, it contacts the copper fingers of the Bakelte base. Looking at the structure, the most likely thing to go wrong is dirt interrupting circuit. The contact points can easily be cleaned with a cotton bud without further disassembly. The central contact is riveted to the inner end of the switch shaft and may be difficult to reassemble if removed. -- Reassembly is the reverse of above".
Note from Barney:
These are "gross motion switches", meaning that the moving contacts slide across the fixed contacts. They are therefore self cleaning in normal service. If the switch is left idle for some years, the contacts may become somewhat corroded and lose electrical connection. The common cure for this malady is to simply operate the switch about a hundred times to rub the contacts clean.