The AM Forum

THE AM BULLETIN BOARD => Technical Forum => Topic started by: Knightt150 on July 22, 2009, 02:38:52 PM



Title: Johnson Ranger meter light
Post by: Knightt150 on July 22, 2009, 02:38:52 PM
I own two Johnson Rangers both have a small crack on the front of the meter and so dose every Ranger I have seen. This has got to be the #51 light bulb inside creating to much heat. Has anyone ever thought of a way to get the heat out or dose anyone know of a LED replacement for this problem.

Thanks John
W9BFO


Title: Re: Johnson Ranger meter light
Post by: K3ZS on July 22, 2009, 04:26:46 PM
Here is a place you can get #47 LED replacements:

http://www.centsibleamusements.com/pinball-led-44-47.aspx

You could make a replacement with a white LED, a resistor (and diode if fed by AC of a higher voltage than the PIV of the LED).



Title: Re: Johnson Ranger meter light
Post by: K3ZS on July 22, 2009, 04:38:31 PM
Another place, look under BA-9 bulbs, the #47 replacement should work for a #51:

http://www.superbrightleds.com/BA9S6_specs.htm


Title: Re: Johnson Ranger meter light
Post by: Jim, W5JO on July 22, 2009, 05:12:54 PM
Another place, look under BA-9 bulbs, the #47 replacement should work for a #51:

http://www.superbrightleds.com/BA9S6_specs.htm


The 47 bulb is a 6.3 volt bulb, the 51 is a 7.5 volt.  Using a 47 should result in more heat and brighter light if the circuit is 6 volts.


Title: Re: Johnson Ranger meter light
Post by: K3ZS on July 23, 2009, 10:14:49 AM
With the LED I don't think you have to worry about heat, I also believe the difference in voltage, would not matter.   In the Ranger the 51 (I don't really know) is probably being used with 6.3 VAC.   One difference would be the clearance, the 51 has a smaller bulb than the 47.    On a side note, I have replaced all #47 bulbs in my boatanchors with #1847.    They have four times the lifespan according to specs and I think they use less current.    They probably are not as bright but I don't notice that in use.
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands