I got two Jacob A60s from a recent deal. One of them works fine, but the other doesn’t work. More specifically, if the tailcap is screwed all the way in, the light doesn’t work. If I unscrew the tailcap slightly, it does work, but I have to unscrew the “exact” amount.
I’ve tried this with several different unprotected and protected batteries, and the problem still persists.
Also, if I move the tailcap to the other A60, I have the same problem, i.e., the problem follows the tailcap.
I’ve tried to disassemble the tailcap, but so far, I haven’t been able to unscrew the retaining ring.
I've had that same problem with one too. In my case it was the driver that lost contact with the retaining ring. I made a ring of solder and put under the retaining ring so it kept pressure on the driver at all times.
Sorry that it’s taken me awhile, but… YOU WERE RIGHT :)!! I was able to get the tailcap apart.
Here’s some pics of what I found:
Both solder joints from the switch to the switch PCB were pretty badly cold-soldered, but that solder joint in the pics had actually broken. I re-soldered both joints and the light now works ok.
Per my post to Sirius9, my problem turned out to be a broken/cold-soldered joint from the switch to the switch board. But, while I had the tailcap apart, I put some solder points on a couple of points on the ground trace on the board to get better contact from the board to the retaining ring.
The soldered joints for the spring were also pretty cold, so I re-soldered those points also.
No, not really, I feel the same, you bought a final product not parts or unfinished product so it should work out of the box.
Anyway, It’s even better feeling when you solve the problem or make a great light out of just ordinary light
Nice to see Jacob working again.
or at least try 
