pishta

I grabbed a few needles off some 92-94 SC junkers and brought them home. None lit up with a 9V battery across leads (looking at needle contacts with needle pointing down: left is - and right is +) so I started probing the trace with my DMM set to continuity. ALL the needles had OPEN TRACES from the pin contacts to the ends, some in multiple places. One had an open right between the contact and the first mount point, less than 2mm down the trace, And the trace has a rainbow hue which indicates that it got pretty hot in its past life. Perhaps the capacitors breakdown caused too much voltage to the tiny traces burning them open? now to repair: first thought was to solder copper wire strands down the entire trace on both sides but I think that would be way to difficult and also make it too fat to fit back in the channel. So second thought which I saw somewhere is to paint the trace with conductive defroster trace repair paint. I believe I can do it while the LED strip is in the needle, otherwise I can do it outside and put the LED strip back in the needle but there is a risk of flexing the white strip and causing the brittle paint to crack. Dont know if anyone has found this out and just replaced the LEDs with an easier fix or what, but Im pretty sure this is the root of the issue. all 4 needles had open traces..coincidence?

t2d2

iTrader: (8)

I've read that conductive paste used for computer CPUs will transmit the signal across those little cracks, but I haven't tried it yet.

pishta

I used some stuff called "electric paint"
in an attempt to bridge all the opens in the 2 traces going down the edges of the needles. I had to remove the LED strips from the needles by using a dremel and grinding out the 3 plastic melt points at the base of the needles. Just zip the heads off and the white portion will pry up and come out. I slid them out in an attempt to keep the white parts crack free as they are very brittle from years of heat. After I got them out and Ohm'd out the opens (all were open between the right socket and the strip!) I used the paint to make a path from the socket, across the plastic corner, to the edge of the LED strip and all the way down to the end. I used a toothpick as its a pretty small bead and you want it to be somewhat uniform. I did both sides and set it under a lamp for 15 minutes to cure. The stuff says it becomes conductive when it dries. Sure enough my DMM measured contunuity from end to socket now on both sides with no shorts. I tested them with a 9V battery and to my dismay, I only got about 25% of the LEDs to light up in all of my 3 attempts. I dont understand why i didnt get 100% but it may be because the traces are coated with something that the paint went over. When I get some more needles Ill use a bit of sandpaper on the sides first to see if that helps. So for $11 you may get some light back, but I dont think itll be back 100%. I looked into some powdered metallic trace paint, but that stuff is really expensive for the amount you get and it comes in a pen applicator, not ideal for what I was trying to accomplish. Your mileage may vary. My next attempt will be to make a 2 wire "stick" with tiny surface mount 5V LED's down its length and transplant that into the needle housing.

oldManTan

for 5 dollars and a soldering iron you can completely replace the LEDs