Hi Guys,
I am sort of reviving an old thread: "12 vdc Inductive ignition timing light bulb weak flash?".
The other day I took out my old Sears timing light #244.2138 to time a guy's 1963 283cu engine. The thing didn't light up. So I searched the internet for troubleshooting and found a good thread in here (see above link). I did the things suggested and didn't find anything wrong. So then I tried testing the capacitance on each capacitor, since I figure that capacitors are good for about 15 years, and this is much older than that. At first I didn't disconnect a leg and just touched across the capacitor legs to test them and that didn't work. I haven't done electronics testing in over 2 decades, so forgot everything I once knew about it. Anyway, when I touched one side of one of the trigger circuit capacitors with the neg lead connected to the neg side battery lead, the neon light began humming and lighting up. So I put it back together and tried it but nothing happened.
So then I began testing each capacitor one at a time by first disconnecting one leg of each and testing across both legs. All capapcitors tested OK, at least using the DVM capacitance testing function. If memory serves, that doesn't test for them under load, but I remember how to do that. Anyway, in the process of disconnecting one leg of each capacitor (one at a time), I found one of the capacitors with a loose connection at the trace solder joint. Unfortunately, I don't recall if it was C2 or C4 that was loose:

Anyway, after I checked all the capacitors and soldered the loose one back to the board, I decided to re-solder every connection to the board just to be safe, since some of the smaller solder joints looked cheezy and weak. After that, I plugged it back into my 12VDC/3A power supply and it still didn't work. But something did happen. The Q1 transistor began to heat up and smoke. Yikes! Now I dune it!
Anyway, I just hate throwing out a perfectly good timing light that just needs a simple repair.
Any chance someone can guide me through troublshooting of this board?
Thanx...Chris
PS: Parts breakdown diagram (got it from another thread in this forum)

I am sort of reviving an old thread: "12 vdc Inductive ignition timing light bulb weak flash?".
The other day I took out my old Sears timing light #244.2138 to time a guy's 1963 283cu engine. The thing didn't light up. So I searched the internet for troubleshooting and found a good thread in here (see above link). I did the things suggested and didn't find anything wrong. So then I tried testing the capacitance on each capacitor, since I figure that capacitors are good for about 15 years, and this is much older than that. At first I didn't disconnect a leg and just touched across the capacitor legs to test them and that didn't work. I haven't done electronics testing in over 2 decades, so forgot everything I once knew about it. Anyway, when I touched one side of one of the trigger circuit capacitors with the neg lead connected to the neg side battery lead, the neon light began humming and lighting up. So I put it back together and tried it but nothing happened.
So then I began testing each capacitor one at a time by first disconnecting one leg of each and testing across both legs. All capapcitors tested OK, at least using the DVM capacitance testing function. If memory serves, that doesn't test for them under load, but I remember how to do that. Anyway, in the process of disconnecting one leg of each capacitor (one at a time), I found one of the capacitors with a loose connection at the trace solder joint. Unfortunately, I don't recall if it was C2 or C4 that was loose:

Anyway, after I checked all the capacitors and soldered the loose one back to the board, I decided to re-solder every connection to the board just to be safe, since some of the smaller solder joints looked cheezy and weak. After that, I plugged it back into my 12VDC/3A power supply and it still didn't work. But something did happen. The Q1 transistor began to heat up and smoke. Yikes! Now I dune it!
Anyway, I just hate throwing out a perfectly good timing light that just needs a simple repair.
Any chance someone can guide me through troublshooting of this board?
Thanx...Chris
PS: Parts breakdown diagram (got it from another thread in this forum)
