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Lighted meters Astron Power Supply
Posted: Tue Jan 18, 2011 9:12 pm
by W8FCD
I have two new lighted meters for the RS-35M power supply which will replace the original non-lighted meters. I would like to know if 12 volt bulbs are used and if so, can they be connected directly to the lighted "On-Off" rocker-type power switch for quick and easy soldering. Tnx. W8FCD
spz1@att.net
Posted: Thu Jan 20, 2011 12:27 pm
by KE3W
Until someone pipes in with a solution - I found some interesting threads on the RS-35M...
Meter lights on some Astron models!
Replace Astron RM-35M Meter Lamps With LED's
Posted: Thu Jan 20, 2011 1:04 pm
by W8FCD
Let me qualify an error. Shortly after my initial posting, I caught an error, I realized I mentioned the possibility of wiring the bulbs to the "ON-Off" rocker switch -- that switch is wired to the 110 volt supply which obviously would "blow" the 24 volt bulbs!
There are a few articles where users have used LED's with great success. However, after further checking directly with Astron, I learned that the bulbs in their new meters are 24-volt, and are connected to the 20-volt source inside the power supply. I initially connected them to the regulated 13-volt source but that's not nearly enought to properly light the bulbs -- they were much too dim. Despite 20-volts for the 24-volt bulbs, several Astron owners claimed the bulbs were burning out much too soon.
After further checking with Astron directly, I decided to insert a 1-watt, 20-ohm resistor in the line and use the 20-volt source. This should light the bulbs properly and lengthen their life span.