[Kenwood] Dial Light

Fri Mar 5 23:54:26 EST 2010

David KW4DH wrote:
>> What is the bulb used behind the frequency dial on a
> VFO-120. The 
> manual has no bill of materials and the schematic refers to
> it only as a 
> pilot light.
>> David
> KW4DH

Clif KA5IPF wrote:
>> 12v 40ma Grain of wheat.
>> Clif Holland KA5IPF
> www.avvid.com

IIRC, they're a 'T1' bulb size. A well-stocked model supply store will have them. Some will have bulbs rated at 14V. These will last a lot longer than ones rated at 12V (when using a 13.8V supply).
Another idea is to use 12V bulbs with a series current regulator IC (LM317LZ + one resistor) to limit the cold-start current. The resistor sets the current limit point. If you choose a current limit less than the hot current of the bulb, it'll last longer than the typical 10,000 hours. Yeah, GOW bulbs are cheap but sometimes they're a PITA to replace. The LM317L datasheet on National's website shows how to select the resistor.
vy 73,
Bryan WA7PRC