Driver issue..electronic experts care to explain?

Hey i'm having an issue with my kd xml driver..i turn the light on and nothing i have to half press the tailcap (like you would do to change modes on a reverse clicky) and then the light fires up..I can then cycle through modes but when it comes to hi again there's nothing..it skips high altogether and goes right to medium..the only way to get hi again is to turn the light off for a few seconds and then repeat the full click half press deal..luckily the memory went out also so that makes this possible..could this be a short on the other side of the board? i'm at a loss as to why this would happen..

thanks

you use a protected battery?

...test another battery, if you have no other, test a near empty battery.

i think, it´s the protection of the battery ;)

nah it was working perfectly from day one with the same batteries and all of a sudden it started acting weird like this..i've run a few batteries down in this light and nothing changes..it definitly seems like a driver issue..

If it's the driver I'm thinking of, it has low voltage protection where it will automatically kick it down to med/low. Check the battery voltage, which I'm assuming you've done. Sounds like it's your switch. Easy way to check is to remove the tailcap and bridge over from the body to the battery. If everything works as it should there, I'd look at replacing or trying to fix your clicky.

ok,

...because i have the same problem with newer batteries and some XM-L lights/drivers.

yeah i've tested the tailcap..should have added that to my original post..even when checking tailcap amperage I have to touch the leads and then take one lead off and retouch to get the light to fire..just as i have to do with the tailcap clicky..

Make sure there is good connection between the pill and bottom of driver board. Also make sure there aren't any problems with connection of the positive battery terminal. You might hold the pill in a vise and then run leads directly from the battery to the right places on the driver and see if you're still having a problem. Seems weird that the driver would crap out only on High, but the current could be overheating something on the board . . .

[quote=pounder]

yeah i've tested the tailcap..should have added that to my original post..even when checking tailcap amperage I have to touch the leads and then take one lead off and retouch to get the light to fire..just as i have to do with the tailcap clicky..

[/quote]

Ah...Ok. Then at this point I would take a look at all the solder joints, specifically the ones going from the driver rim to the pill and the ones going to/from the LED/driver. Sounds like the extra pressure from going to half click is helping a bad connection act good.

good idea running the leads from the battery..i'll try that to see if it helps..

Might be the driver itself. A swap can clear any doubts. Try the famous 2.8A from kd if nothing else helps. Should be way better than the stock one anyway. A good XM-L flashlight could use a good driver.... :)

yessir..got 3 of those drivers coming from kd right now..they should have been here this week but oh well..should I piggyback another 1735 to make it 3.1? from the lumen ratings I don't think there's any advantage to 3.1 over 2.8a other than heat..what say you? I am just interested in why this driver would act this way..trying to learn the complexities of the cicuitry is all..when I replace the driver i'll go over the other side and check for a short on the board..

tried leads right to the contact on the driver and no dice..same half touch thing happens..

well removed the driver from the pill to check for a short on the other side..everything looked fine so i reinstalled the driver..to my amazement everything now works perfectly and memory is back..I don't know how to explain it but maybe a lead was touching something it shouldn't have been..pretty cool..

Is this the one (I mean the good one)? http://www.kaidomain.com/ProductDetails.aspx?ProductId=10995