I have several of the SK68 clones. Some of them do not work but if I put the tailcap from a working one on then they work. Is there anyway to repair the tailcap switch on these things? Do you think that is actually the problem or something else.
I would disassemble the tailcap and replace the switch. With that said I don’t know what the insides of any SK68 tailcap looks like, I don’t have any, so I wouldn’t know exactly which switch to get as a replacement. Others here can surely help with that.
Welcome to the forum. Do you have a way to post pictures? It’s extreme helpful in diagnosing problems. Tail caps often employ a threaded ring that screws down on top of a pcb which has a spring soldered to one side and the switch to the other. One common problem is the battery tube not screwing in far enough to make contact with this threaded ring. If the tube and tail threads are anodized then this contact is how current flows between the tube and the switch. If the threads are not anodized then the problem could be a bad solder joint to the switch or a bad switch itself. If you have a DMM you can check continuity between the spring and retaining ring or deanodized threads to see if the problem is in the switch pcb. Retainers have dimples that allow a tool to spin them in/out.
The switches are the weak points on the SK-68s. I was able to take mine apart by chiseling and prying the plastic retaining ring out. I've never been the fan of the SK-68 like so many are on here, so I never really tried to repair it, other than re-assembling. I ended up replacing the tailcap with a battery extension tube, discussed here:
I tried the above repair on one light to no avail. The switches themselves are plain junk on the ones I had. Even after stripping them and cleaning no success was to be had.
The ones I have taken apart use the same spring for the switch and for the battery contact, so separate switches won’t fit.
If there is nothing obvious and cleaning doesn’t help, I would order some more SK-68s and mix the best parts together. Or else stick to UltraOK and maybe Sipik brands that are likely to work better. The problem I have had with the cheap clones is very poor tail cap threads.