MG T-ABC

I love the look of an incandescent indicator bulb.
Comparatively, LED's look like garbage.

However, they do have one flaw, that is when they no longer bulb, sometimes.

Fortunately, I had access to a large collection of incandescent light bulbs of various types, and I was able to find some suitable bulbs to replace the TC originals without much (or any) modification.

For the dash indicators I found the GE #313 28v 5w bulb. This eliminates the need of the 70 ohm wirewound resistor. To do this fix, simply solder a wire from the bottom of the bulb, remove the center contact from the housing, remove the 70 ohm resistor, and insert the bulb. Given its 28v rating, it should be guaranteed to last there for ~20 years or more.

Please take note: the 28v bulb may not have enough resistance in it to provide adequate field current for the generator at starting. A 70 ohm resistor in parallel with the lamp should fix this problem.

For the Map lights, I discovered that a Sylvania W-67 bulb fits in, no modifications at all.

Thanks for the tips.

I don't think there's any need to be concerned about providing adequate field current at start up as the field contacts in the regulator are initially closed, directly coupling the dynamo output to the field winding.