[Boatanchors] pilot light substitutions

[Rod Hogg]

Dick.

Chicago Miniature lamp catalog shows Type 50 Bulb, 7.5V @ .22A, Type 51 Bulb
7.5V @ .22A.  Same thing, the type 50 is screw-in and 51 is min bayonet.
The type 50 is a RadioShack stock item, the E-10 bases are there too.  They
have the bayonet sockets, but not the type 51 lamp.  It is VERY common in
older two-way radios, i.e. Motorola control heads, etc.

Don't see any other subs at 7.5v.

I have both if you can't find any.

Rod
KØEQH


-----Original Message-----
From: boatanchors-bounces at mailman.qth.net
[mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Dick KF4NS
Sent: Wednesday, September 16, 2009 2:19 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] pilot light substitutions

I do not have a 51 bulb (somebody changed the socket, orig. was a 50) 
for my Heathkit VTVM but lots of others. Has anyone done substitutions 
for this bulb or any others without changing the type of bulb socket 
and is there a rule of thumb for the type and value of a limiting 
resistor if I use a lower E and I rated bulb?

Kind of hard to calculate without breaking out the tube data for 
min/max filament  I&E on each tube in series and then consider the 
aging of the tubes, then get the full data on the bulbs, etc.

Your advice will be appeciated.

Thanks and 73, Dick KF4NS
St Petersburg, FL 33714 USA
Keep The Glow!




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