[Milsurplus] Solid State Frankenbulbs for R-1051, etc.

[John Watkins]

Hi All,

Found my write up on the LED lamps.  Hope it is usefull, mine are still going.

John

Just made 2 White LED "Frankenbulbs" (thanks Nolan) for my R-1051.  The LEDS used are the Radio Shack variety.  I followed Nolan's procedure (see his web
site) for separating the lamp into 2 parts (One the base and one the brass sleeve with plastic insulator (leave the insulator on the brass sleeve), then used a Dremal tool to remove the adhesive and bad bulb from the brass sleeve part.  Next step was to epoxy the LED into the brass sleeve part of the bulb.  I then drilled 2 small holes in the base portion of the lamp one for the neg lead of the LED, and one to put more epoxy into after the final assy.  After the epoxy set around the LED, I cut 2 small slits with my dikes (small wire cutters) the width of the pos lead on the LED and folded the resulting small piece of brass sleeve wall down (toward the inside of the brass sleeve).  I then bent the pos lead into the resulting notch, and soldered it to the bent down piece of brass sleeve wall. Next I dressed the resulting solder blob (not really a blob) down with some careful work with a jewelers file (just want to bring the surface back to original
 dimensions).
Next job was to press fit the 2 parts back together again (this is why we used the jewelers file on the solder blob), sliding the neg lead through one of the holes in the base.  I then soldered the neg lead to the base, once again using Nolan's method of putting the brass sleeve with plastic insulator in a bit of water so that I wouldn't damage the plastic insulator.
Next was to put a drop or 2 of epoxy (love that stuff) into the last open hole in the base.  
I now had a solid state "Frankenbulb".  These just screw back into the holders with no further modifications.  Cost was around $4.  

Last thing to do is replace R1 and R2 on the power supply board to get the proper milliamps through the LEDs.  I found that they will light up at 2 mills, and are very bright at the recommended 20 mills.  Way to bright for my taste.  I calculated the needed resistors for 4 mills and used 2 1500 ohm
1/2 watt resistors.  You can adjust these to what ever brilliance you want.
The White LEDS are rated for 20 mills.  Don't forget they are in Parallel.
Also, if you don't like the bright white color, a bit of iodine on the LED gives a sort of orange glow to the light.  So far mine have been on for 6 days and no problems.
I will do a proper write up and take a couple of pictures.  Have to email
Nolan and see if he will put it with his "Frankenbulb" procedure.   
A few things to keep in mind:

1 Identify the pos and neg leads on the led and mark them.

2 Go slow and be sure and look at Nolan's website for instructions on how to take the Grimes lamps apart.

3 Test as you go.  I checked the assy. after each step to make sure I hadn't gotten a lead reversed, etc.

4 Check your R-1051 power rails to these bulbs.  Mine were brass sleeve pos and lamp base neg, but yours may be different.

5 Both of my Grimes lamps were made of Tin plated Brass (both the base and sleeve), made soldering easy.  I am not sure if all of them are that way.
Perhaps Nolan could shed some light on this as he has done more of these than I have.

John  WD5ENU/A45XV