Results 1 to 16 of 16
  1. #1
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112

    Bonking ... not feelin' well Please help My light stopped working

    Hi all,
    I bought a troutie 6XPG light kit awhile ago now(maybe 12 months) its been working great. but for some stupid reason when i turned it off the other day it wont come back on. i pulled it down and tested all connections and they all work. 16v from battery 2.3v across switch. all LEDs light up when multimeter is on them. do you think my driver may have died?
    I did notice when it was open with power supplied a small amount of smoke appeared and the driver is getting very hot. I have been using this light for 4 hour night rides on high the whole time with no issues. how do i check if power is going to the LEDS?
    Please help im scared of the dark.

    Thanks Josh

  2. #2
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    After closer inspection, it must have gotten very hot, a resister has desoldered itself. Ill upload a pic soon so someone can tell me if i should reconnect it. George??????

  3. #3
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    Here are the pictures of the missing bit
    Attached Thumbnails Attached Thumbnails Please help My light stopped working-p8220094.jpg  

    Please help My light stopped working-p8220095.jpg  

    Please help My light stopped working-p8220096.jpg  


  4. #4
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    sorry about the big pictures. i forgot to resize them

  5. #5
    Drinkin' the 29er KoolAid
    Reputation: kwarwick's Avatar
    Join Date
    Jun 2004
    Posts
    1,010
    Based on the silk screened D1 on the board, I'd say that's a diode that has detached. I'm betting that's the diode for reverse polarity protection, so with it missing from the board you've got an open circuit between the battery and the driver.

    The obvious question is why did it detach? I notice the Maxflex is just floating around in the case.. it should be glued in place with thermal epoxy as it needs the case as a heatsink to prevent the driver overheating. So if you didn't pull the driver lose the n perhaps the driver overheated enough to cause the solder holding D1 to let go? hmmmm...

  6. #6
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,295
    Interesting thread.
    George should have a good idea of what happened I bet.
    Isn't the reflow solder temp around 400F. Can't imagaine the maxflex getting that hot from currrent and not having one of more of the board components shut down.
    Sort of remember George mentioning some sort of switcher that will shut down at higher temps.

  7. #7
    mtbr member
    Reputation: bwack's Avatar
    Join Date
    Oct 2009
    Posts
    62
    Diodes overheat when if current is high, OR it has failed to operate correctly.
    A failed switching transistor (U2?) can cause high currents.
    You may have had an short-circuit to the enclosure. It is floating afterall..Inspect the rear side for any burns.
    Luckily the diode worked like a fuse.
    Edit: I was wrong with the failed transistor. I was thinking of a Buck-driver, but this is a boost driver. see Georges answer below.
    Last edited by bwack; 08-23-2010 at 02:05 AM.

  8. #8
    Drinkin' the 29er KoolAid
    Reputation: kwarwick's Avatar
    Join Date
    Jun 2004
    Posts
    1,010
    Quote Originally Posted by bwack
    Diodes overheat when if current is high, OR it has failed to operate correctly.
    A failed switching transistor (U2?) can cause high currents.
    You may have had an short-circuit to the enclosure. It is floating afterall..Inspect the rear side for any burns.
    Luckily the diode worked like a fuse.
    Agreed, and looking closely at the picture of the diode I believe I see a crack in the casing which would tend to support that it saw very high current and probably got red hot before it detached. A short to ground is the most likely cause.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    i pulled the driver out to see whats going on. is was glued in place with thermal adhesive and i also had some silicone to help hold it where it should be. Looks like i'm up for a new driver then?

  10. #10
    help with the zip please
    Reputation: emu26's Avatar
    Join Date
    Jun 2008
    Posts
    3,966
    Did you have thermal protection set?

  11. #11
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    not sure. I don't remember what settings I had when I first built the light

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    287
    The diode is the schottky diode feeding forward from the inductor in the switcher core. Being a boost driver, the schottky is in direct series to the LED load.

    For the diode to have melted the solder I'd lay 100 to 1 odds that you had a short circuit in the LED array to ground (chaffed wiring etc etc etc).

    Basically being a boost driver there is a direct DC path from the battery through

    a) reverse polarity FET
    b) inductor
    c) schottky diode
    d) current sense resistors

    to the LED load.

    With a short at the output and given the low resistance of a) b) and d) most of the power dissipation will occur in the c) the schottky diode and it would have melted off first and acted as a fuse.

    I've had a few folk report melted off diodes due to 'momentary' shorts on the output...

    Unfortunately with the diode out of circuit, the switcher IC would have bit the big one, so replacing the diode will not 'repair' things.

    So,. end result, you have a dead maxflex due to a short in the output section of your light system.

    cheers,
    george.

  13. #13
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    Quote Originally Posted by georges80
    The diode is the schottky diode feeding forward from the inductor in the switcher core. Being a boost driver, the schottky is in direct series to the LED load.

    For the diode to have melted the solder I'd lay 100 to 1 odds that you had a short circuit in the LED array to ground (chaffed wiring etc etc etc).

    Basically being a boost driver there is a direct DC path from the battery through

    a) reverse polarity FET
    b) inductor
    c) schottky diode
    d) current sense resistors

    to the LED load.

    With a short at the output and given the low resistance of a) b) and d) most of the power dissipation will occur in the c) the schottky diode and it would have melted off first and acted as a fuse.

    I've had a few folk report melted off diodes due to 'momentary' shorts on the output...

    Unfortunately with the diode out of circuit, the switcher IC would have bit the big one, so replacing the diode will not 'repair' things.

    So,. end result, you have a dead maxflex due to a short in the output section of your light system.

    cheers,
    george.
    Not what i wanted to here. but thanks George for letting me know. Should i just order another one from Cutter? at $60 i hope it doesn't happen again.
    Thanks Josh

  14. #14
    mtbr member
    Reputation:
    Join Date
    Jan 2007
    Posts
    754
    Quote Originally Posted by Joshp82
    Not what i wanted to here. but thanks George for letting me know. Should i just order another one from Cutter? at $60 i hope it doesn't happen again.
    Thanks Josh
    You'll need a new one either from Cutter or directly from taskled.com. But, I wouldn't just replace it and hope for the best. That could end up being rather expensive if you keep blowing drivers. You need to investigate and figure out the root cause of the problem.

  15. #15
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    112
    From what i could see when the driver was out, it wasn't sitting 100% flat on the heat sink and I'm not sure what temp i had the thermal cut off set to or if i even had 1 set. I'll just have to make sure everything is perfect next time. is an expensive lesson but 1 i will learn from.

  16. #16
    mtbr member
    Reputation: troutie-mtb's Avatar
    Join Date
    Sep 2007
    Posts
    3,049
    Just looking at the pictures there is a lot of bare wire sticking out of both the ground and the led posative .
    and as George said his odds were a short from the leds to ground then could it be possible for a stray strand to have shorted and done the damage

    I go away at the end of the week and the offer is still there

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •