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417

Finally i receive replacement driver from Haikelite yesterday. I took out problematic driver but i haven’t put new driver into light yet because i want to do comparison and repair the problematic driver, possibly with power supplied to them. Visually they are similar and no fault can be found. I also assume the replacement is good driver.

I did unsolder C3 but it didn’t help, still have very dim light leakage.

Without supplying power, I measure the big FET Rdsoff between LED- and ground, new driver is in 6.xMohm while problematic driver is in 4.xMohm range. Not sure is that and issue. Maybe i should supply power and check this Rdsoff again.

Anyone knows what is this big FET below? Wish to read its datasheet to understand more.

418

Vishay SIR800DP

419

The SIR800DP has been around a while - Richard at MtnE has been selling them - it's a very good FET, stays cool under high amps. I thought it was pretty much in agreement the SIR404DP was superior, next step up, then is the SIRA20DP which I currently use as one of my two choices. The other is the Infineon BSC009NE2LS5ATMA. I usually use the Infineon now - great specs. I believe others have had problems with the SIRA20DP.

The SIR800DP is not a bad choice for this light.

420

Thanks both of you for the info. I shall report back soon.
I wonder is SIR882DP new version of SIR800DP.(updates:looks like they are for different range)

421

I would take my multimeter and measure the resistance on U3 from the big pad to one of the three smaller pads. Compare the 2 drivers. I think you already did this. 4 and 6 million ohms is pretty much infinite resistance, so I don’t think that is a problem.

I think you can do the same thing for U4 measuring the pad on the left and bottom.

I’m kind of guessing on this, though.

422

Um, it’s 4/6 miliOhms, not MegaOhms.

423

You sure? He used a capital M instead of a lowercase m. The miliOhms range is like a dead short.

I have a 3v 3 channel TA driver here. I tried to measure across the FET and got 1K ohm. Across ch 2 I get inconsistent readings. Across the single 7135 I got 4.5k 1k ohms. (Had to break our my new Probe Master test leads. DMM is still crap, though. Lol)

424

Oh you were talking about the resistors, not the RDSon of the FET.

425

IDK, I’ll leave it to TA or someone who knows these drivers really well. He built it afterall. Lol

426

It is Mega. I conveniently call it Rdsoff. :blush:

427

Does your new FET able to fix the issue?

428

I don’t have suitable FET for it. I have only a replacement driver sent by Haikelite.
Before I install this new driver into the light, I wish to investigate how to repair the problematic driver.
Being busy at work that I can’t troubleshoot it yet.

429

I troubleshoot it and can’t find any fault on voltage. There is no voltage that can turn on U2 and U4. U1 has proper 5v power. There are difference below.
1.Voltage between LED+ and LED-
Problematic driver has 410mV while replacement driver has 320mV.
2.Resistance between LED- and ground
Problematic driver has 51Mohm while replacement driver has 68Mohm. I think my previous resistance measurement done a few days ago was wrong on decimal point.

Both drivers have similar current consumption, boot up with 6.8mA and then to 7.3mA and then to 56.5uA. This is without LED connected.

430

The FET is supposed to be the SIR800 posted before, this is what I used in the drivers I hand made and have not heard of any issues with the 100+ that are floating around.

The production drivers though have used fake FET’s in at least a few of them, it was supposed to be corrected but no idea if it ever was.

The fake FET’s are most assuredly a problem and not up to the task of this light for extended use.

Without specialized equipment it can be very hard to test an FET properly. It is generally easier to just swap it out and see if that fixes the problem. This is the first thing I would try personally, for the $1-3 it would save a lot of time in the long run.

The other option is the small FET for the 1st channel could be an issue as well but far less likely since it sees a max ~0.5A.

431

Ya, I agree the easiest way is to swap the FET. Too bad I don’t have any suitable FET at this moment.

Is this Vishay SiR164ADP suitable? FET

432

I used the SIR404DP and SIRA20DP - haven't seen the SIR164AP before. The SIRA20DP and Infineon are the 2 I use now.

That Rds spec looks high to me, compared to the A20. The A20 is pretty spectacular in specs.

433

For testing basically any FET with the same footprint would work.

Heck you could just remove the FET and see if the leakage stops, if so then it is a very high probability you found the problem.

434

A20 is indeed very low in Rds. Thanks for pointing out. Thanks Tom E.

I will try to get the FET removed then. Just need to get my friend’s help with his hot air. Thanks TA.

435

I have taken out the FET with hot-air and solder the board back to the light with just LED+ and LED-, the leakage is not seen. It blinks two times when batteries make contact and then no visible leakage. I was happy for a short moment.

And then I put the replacement driver into the light by soldering all the five wires, the leakage is still there. Looks like replacement driver is not good either. :person_facepalming: Light function well, just it has this annoying light leakage during off.

436

Oh boy, not sure, but thought I seen someone post that some of the LED's may be the cause but I would think you would see it only that LED or LED(s), not all the LED's? Shame because I don't think I've seen this problem in my limited # of lights with this kind of driver and power.