Joined: May 2018 Posts: 2,953 Threads: 558
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Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
Has anyone experienced the ignition warning light on a Ruby failing to work? The bulb has been tested and is OK; the ignition and charging systems both work (having worked out where the wire I pulled off went) but no red light. A clue: when pulling out the dash panel (don't you just love those seven inaccessible 4BA screws) there was a short-circuit and the main fuse blew. Having persuaded all the instruments and dash lights back into life, just this one little problem remains.
Another question: on the Seven, does the ignition light bulb (2.5-volts, 0.2 Amps working through 30-Ohm resistor) provide a "trickle charge" to get the dynamo charging?
Joined: Aug 2017 Posts: 926 Threads: 22
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Location: Near Cambridge, UK
Car type: 1928 tourer (mag type), short chassis Gould Ulster
Because of the way the ignition light is wired it does allow a very small current through the dynamo, but that has nothing to do with getting the dynamo charging. It is the small amount of residual magnetism which does that. When the ignition lamp has failed the dynamo should still charge. If the bulb is sound with good connections it may be that the wire wound resistor around the holder has broken. If this proves to be the case I suggest soldering a direct connection across the terminations of the resistor and using the lowest wattage 12 volt bulb you can get (old fashioned panel light bulb) in place of the original 2.5 volt. This will glow adequately when you switch on, and go out the same as its predecessor when the dynamo starts to cahrge.
Joined: Aug 2018 Posts: 190 Threads: 5
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Location: Dorset seaside
13-08-2021, 12:36 PM
(This post was last modified: 13-08-2021, 12:36 PM by Nigel Ricardo.
Edit Reason: spelling
)
Ref the BA screws and the faf trying to put the nuts on, I now use rivnuts to hold the panel, far quicker and no risk of pulling the wires off.
Joined: Aug 2018 Posts: 190 Threads: 5
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Location: Dorset seaside
Yes they were metric, the equivalent to 2 BA so they looked the same from the front
