TK 40 Technical Problem

Just got my TK40 in the mail 3 days ago. Played with it one night outside and all was functional. All 8 modes and it was an amazing light.

Now today i grabbed it to play a bit and i ran it on high for about 7mins and then it started to flash intermittenty at random intervals. I felt the light and it wasn't warm to the touch, but it shut it down anyway to let it cool.

Turned it back on and now i only have low and low strobe. I cannot access any other mode no matter how many times ive tried.

I found two good posts on CPF that led me through checking the battery carrier contacts, cleaning contacts, springs, threads, disassembling the tailcap and switch and checking the electrical connection via a bridge with a paper clip.

All things check out and none filxed my issue with only being accessible to low mode and low strobe.

What controls the modes toggling? is it the switch or the diode piece of silicon the tailswtich mounts to?

Or is it controled by the silicon on the head?

I'm bummed. Apprecaite any ideas or links to other threads to check out.

Could energizer AA rechargables have killed something electronic?

Errr.... did you check the batteries?
TK40 flashes to indicate low battery status.
Try charging your batteries...

There is a good chance it's some kind of battery problem. Make sure each battery is good and is holding a charge. Next make sure all the batteries are inserted correctly. It's easy to have one or more batteries improperly inserted. I know it happens. I have done it, so I know.
Good luck
Dave

guys,
thanks for the suggestions. I've tried those things too. i'm not beyond being a dummy at times , for sure, but i have those covered

If you think of something else let me know thx.

Try taking the switch out and giving it a squirt with some electrical cleaner.

After you've cleaned all the contact points, cleaned and re-lubed the threads and made sure the battery carrier is all tight and snug.

I wouldn't mess with any more -- I'd contact the dealer.

do you have a multimeter to check the reading of your battery magazine? mine reads 5.14V with not fully charged cells. With fully charged cells it should read 5.2V - 5.8V (or > 6.0V if fresh alkaline/L91).
try to check 2 places:
- gold plated spring at the top (+) and the silver plate at the bottom (-)
- gold plated spring at the top (+) and the gold plated leaf at the top (-)
you should get the same reading, 5.2V - 5.8V (on freshly charged cells)

here's my battery magazines for your comparisons:


and from another angle:


did you notice a brief flash when you change mode? no? it could be a a problem with the switch, try take out the switch and do a thorough cleaning. When I first got mine, I clean it with some isopropyl alcohol and DeoxIT.

I've got a few other flashlights' switch that need some "work-in" time to function properly. It's still a mystery to me. :thinking:

if none works, you should contact your dealer and ask for a replacement.

The Fenix website has some videos showing how to clean & repair their lights. Given your symptoms, the main thing I'd check is the metal plate in the switch - make sure it's screwed down tight and not loose. There are some indentations in it you can use with needle nose pliers to make sure it's tight.

+1

rookiedaddy said:

Errr.... did you check the batteries?
TK40 flashes to indicate low battery status.
Try charging your batteries...

Click to expand...