[Kenwood] Dial Light

[Bryan Swadener]

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