FET+1 Bistro Not Working properly

problems,
Initially after install into light and first use I wanted to check the heat dissipation. Scrolled through the mode, all seemed fine. On high as it was getting warmer, I could still hold in hand at the head. It just shut off. Took it apart to find the Neg wire melted off the driver board. Soldered it back and light now has no lows. I mean it is the same brightness from ML to 3 out of the 6. Tried to reset and it seems to wants to enter configuration mode but I get no indicator blinks. It is really in config, and while messing with it, I can blindly get menu changes. Tried playing with it again today and now in 2 mode L, H.

Any ideas on the Neg wire desoldering?
Under magnifying glass the board has no visual problems to me.
Light is an unbranded M1 Style host from KD.
Single XP-L HI on 20mm Noctigon.
New type Fet+1 with red wire through board.
LG HG2 batt.

Will pull driver and get (best I can) pics of anything requested.
I am not an electronics expert. and I doubt I could replace a part that tiny. But I would try if its not too fudged.

Nick

Especially check the connections of the 7135 chip

Hmmm, kind of sounds like your OTC may have fried. If you have a spare 1uF (or whatever size OTC that driver uses), you can mount it on top of your existing OTC (that way you don’t have to remove the existing one) and see if that fixes the problem.

7135 is by the Neg wire…

researching OTC…

Trying to get good pics for magnification.
Realizing I am getting OLD.

I would imagine your off-time capacitor is 1uF, but I haven’t been keeping up with drivers for awhile.

Thanks 4W. Found the OTC. Looks OK visually. will see if I can get a spare on the next order.

PD, 7135 pins are not flat on board, kinda look raised.

Getting pics uploaded. I think they are gonna be BIG. Apologies in advance but I am not sure I want to scale them. Will see…

Before this build I ordered variety pack of tips for my Weller. Was able to select 6 from a variety of styles. I got the smallest of the various types I could. May be here tomorrow or Thursday. :+1:

Scale them for the page and link the originals.

Album is public and there are more pics

http://img.photobucket.com/albums/v219/vwpieces/Misc/P_20160830_202904_1_zpsefjquokr.jpg

http://img.photobucket.com/albums/v219/vwpieces/Misc/P_20160830_204204_1_zpsyuh24r1r.jpg

Forgot to mention that earlier, before I locked it to 2 mode I had 6 modes and was able to get it to go Backward into the blink modes.
Assuming the OTC is relative to blinks. I got blink modes but no blinks in configuration.

Yeah, it does seem your OTC is probably ok. The rest of the driver looks good too. The diode looks like it might be a bit burnt. I don’t know anything about how they behave when they begin to fail. Assuming the diode is ok, I think the only other possibilities are scrambled program or fried MCU. Hopefully, someone that knows alot about FET+ drivers comes along.

I can’t tell how good of a connection the 7135 pins have. You can try touching your iron to them to make sure it is good. Otherwise, I have no idea. Ask Richard if you haven’t yet.

I wanted to wait for the fine tip for the iron before attempting to hit the 7135 legs. Just checked Tracking on the tips and it looks like they will be here tomorrow.

For the Diode. Is this the D1 marked on the board, or something else less conspicuous? I have a lighted loupe and the D1 looks normal. The item with TA on it looks funny. It is between, C1 and R1 on the outer edge. Not sure what it is.

Surprised it works at all if it got hot enough to melt the solder on the Neg. There was some solder flung up to the one end of R2. You can see the slight spike I made with the iron to clean it up a bit.

I have repaired boards before but only with specific instructions of what to get and fix. My Onkyo receiver has HDMI board issues and needs capacitors again. I am pretty sure I bought doubles of everything because shipping was more than 2 sets of parts.

Yeah, wanted to see if there was something as a known or common issue before bothering Richard. Got 2 of these with Bistro on the last order. 2nd Bistro is fine and getting 3X the torture and heat, running fine in an S2+ triple XP-L HI.

Maybe the OTC is faulty and perhaps it works till warm.

I like anything DIY and this is a learning experience if it’s repaired or not.

Ta might be the ntc(temp sensor). A wire melting off sounds more like a short caused that which might be what fried the sensor(if it is). Are the springs still ok. A short can pass enough current to overheat them and make them lose their temper(shows as discoloration instead of gold).

I would suspect that something burned up due to a short circuit. The only way to get the LED- lead hot enough to solder off that FET in any normal light is to short it out.

The temperature sensor is inside the MCU, and even if it was wacked it does not step down immediately.

The FET itself could be fried. The MCU sounds like it is OK since it still blinks out modes and enters configuration.