Final Assembly
Lay out the parts as shown below to get an idea of how to cut the wires from the transformer. This is why we marked one wire as (+). If you didn't get (+) marked, you need to set up a test again to find out.
Lay the tube and the parts out somewhere. Place the LED beside the tube, located as if it were assembled, i.e. bottom of the LED flush with the end of the tube.
Position the end of the longer (+) wire so that it overlaps the resistor lead by about 1/4 inch. Mark the back of the probe on the wire and strip apart for the length of the tube
Cut the NEGATIVE (-) transformer wire the right length to connect to the back end of the probe. You will need a little separation beyond the end of the tube to connect the negative wire easily. Strip 1/4 inch, twist and tin both wires.
All the parts should look something like this.
(Final parts layout)
[ATTACH=CONFIG]529702[/ATTACH]
Decide if you want anything to slip over the back of the probe, a boot or anything. I didn't do this, but it would be a nice addition. If so, slip it onto the transformer wire now.
Tin the two spots on the brass tube. Solder spots should be 1/8 to 3/16 inch or so. Make one at the rear end of the probe, at the very end of the tube. On the LED end of the tube, make a spot where you think you need it to connect the negative lead.
(Tinning back end)
[ATTACH=CONFIG]529703[/ATTACH]
(Tinning LED end)
[ATTACH=CONFIG]529704[/ATTACH]
Slide the wires into the tube so that the (+) wire protrudes out of the LED end of the tube. To do this, the negative wire will have to be pulled inside the tube for a little way. It will pull back out later.
Slide the spaghetti or soda straw over the (+) wire. This tubing must be long enough to insulate both resistor connections. Don't let the spaghetti get stuck in the tube.
(LED before tubing)
[ATTACH=CONFIG]529705[/ATTACH]
Tack solder the unused resistor lead to the (+) wire. Afterward, slide the spaghetti or soda straw over the resistor, all the way up to the LED. You can wrap a very tiny piece of duct tape around the wire to keep the spaghetti from slipping back.
(Parts ready to put into tube)
[ATTACH=CONFIG]529706[/ATTACH]
Carefully push the LED and resistor, with the insulator fully covering them, into the tube. If you drilled a hole, bending the lead outward at the end helps to thread it through the hole. Work with it until the LED is flush with the end of the tube. Don't solder the negative LED lead yet.
The negative wire should have pulled back out of the brass tube as you pushed the resistor into the tube. Tack solder the negative wire to the back end of the brass tube. Do this end first for practice. Let it cool. If you chose to have a boot for the back of the tube, it should already be on the wire. Slide it onto the brass tube.
(Rear Solder Connection)
[ATTACH=CONFIG]529707[/ATTACH]
Bend flat and tack solder the negative LED lead at the front end of the brass tube. Be as quick as you can with this one. Let it cool.
(Solder LED into tube)
[ATTACH=CONFIG]529708[/ATTACH]
I finished off the light probe with one and a half wraps of white electrical tape, just overlapping the flange at the bottom of the LED.
(White tape for trim)
[ATTACH=CONFIG]529709[/ATTACH]
I think you're done. Plug it in and see if it works.
John
****** Disassembly For Repair ******
Should you need to disassemble the LED light probe, heat the solder that attaches the negative LED lead to the brass tube. Using the soldering iron tip, push the LED lead to the side, then up and away from the tube. Let it cool. Re-heat and carefully (your eyes) tap against the edge of a wastebasket to shake off excess solder. If only a slight solder connection remains, it may usually be broken with gentle but firm pressure on the wire lead from a small tool. Unsolder the negative transformer wire from the back end and guide it inside the tube. Then carefully pull out the LED.
**************************************