[TenTec] 12v Pilot Bulb

Stuart Rohre Rohre at arlut.utexas.edu
Thu Nov 9 17:51:40 EST 2017


If a #47 bulb seems short lived, or runs hot in your radio, it can be 
replaced with the more dim light of a 4 digit bulb type number that is 
rated for 28 volts.  (Check that the current drain is similar or less 
than that of a #47.) There are several examples with 4 digit part nos.
I want to say from memory 1428 is one such bulb. Just verify the base is 
the bayonet, opposed pins identical to the #47, and same length of brass 
shell, to identically fit the lamp holder, if one is used.

The 28 volt bulbs should still be in Mouser, Digi Key, Allied and other 
large distributor's catalogs.

Some years ago, we replaced many #47 bulbs with 28 volt bulbs, which we 
stocked for tape recorders we owned from Ampex Corp.  I think we are 
down to one instrument with a 28 volt substitute, but it was a pleasure 
to not have to keep ordering #47 bulbs and replacing them. Some were in 
tube based instruments, some in transistor based instruments. Now 
replacement instruments come with long lived LED lamps or indicators.

-Stuart Rohre
K5KVH


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