My recent dqg26650 mod hasn’t gone well. Turning the light on high seems to fry something. The light cannot turn off, like there’s a short somewhere, but not a dead short. Pressing the switch seems to operate the light independently to the permanent on status. I can post a video if that helps to understand the issue.
Driver is MTN17, fet+1, bypass wired by supplier, D4 ui, temp sensor (no turbo timer).
Any ideas on how i can stop breaking stuff…?
There are nothing to brake, very simple driver. Maybe somewhere wrong connection , maybe 7135 dead . When you know chematics its easy to fix it. Take Hi-res picture , maybe we will se something.
Thanks for the reply Quadrupel. I don’t think it was a wrong connection. The light worked perfectly fine before i ramped up into high mode.
I’m not so good with close up pics but here’s the first driver
I put the multimeter across the 7135 pins. I have no idea what it’s meant to read. Going by the readings and the blobby looking solder on pin 3, i guess this component is where the problem is…?
Would the driver work if i removed the 7135 chip ?
should work some how. I have no 7135 on hand to check how it looks new, if you have compare it with old one., or just replace
Thanks for your help Quadrupel 
I’ll see if i can do something with it on Sunday
I’m not sure if the FET has been changed on those drivers, but even recently a rather high resistance one was being used, not suitable for high current. There is also no transient protection, which the T85 and 7135 might be sensitive to.
Swap the fet for BSC009NE2LS5ATMA1, which is the go-to fet, or give SIR178DP a try, which is an ultra low resistance fet rated for 2.5V gate.
You could build a Del driver or TA driver instead, which have the transient suppression passives, but you’d need to order the .8mm thick boards if you want 2oz copper from OSH PARK.
Yes, although in the firmware there are probably two channels defined with corresponding PWM values. The low end of the ramp might simply have no output, until the FET channel is active higher up in the ramp.
I actually had 2 MTN FET+1 drivers where the 7135 died
Just desoldered it and flashed a different firmware
Of the two drivers i think i completely screwed one of them when trying to replace the 7135 chip. During the week I’ll see if the other one can be salvaged with this method. Thanks
I don’t understand a word you’re saying but it’s like you’re trying to communicate with me, i just know it… 
jokes aside though it’s interesting to learn that some fet drivers can’t handle this much current. I’m curious now and want to measure the current when i get it working again
A transient is a voltage spike. The burst of current flow that occurs when the fet turns on at 100% comes along with a voltage spike which can exceed 6V according to this scope by DEL. This could be killing the 7135s. A couple of added passive components will significantly reduce this spike. These are included on TA drivers and Del drivers.
What firmware did you flash?
I’m not overly surprised at the spikes per se but am surprised it gets up to/over 6v from a single cell…?!
I think I just flashed Biscotti from TK’s repository without any modifications
Oh, clicky firmware. I tried to reflash D4 firmware (e-switch) from several years back but low output still runs through the 7135 chip.
Oh wait you have an eswitch
In that case some NarsilM or some pure fet T85 Anduril could probably be flashed.
I don’t have easy access to all hwdefs on the phone but maybe someone else can name one that would fit
Firmware is not a problem here for now, somebody can compile new one or just use stock D4 Anduril,depends on pinout. For now he needs working hardware. He must to reflow proper component first.
I removed the 7135, so it functions as normal except for low modes
OK , so yuo need new 7135… or 1 channel firmware.
