Nanjg AK-47 woes

Hi, Regarding:3* AMC7135 4-Group 2~5 Modes LED Flashlight Driver Circuit (Nanjg AK-47A)
Nanjg AK-47A: 1050mA / SKU: 1122400 from Fast tech.

I have used umpteen of these in the past without problems but am having issues with the latest two batches. I am following these instructions: Connect the 3rd star from the left to ground: 3-mode: Lo (5%) > Mid (30%) > Hi (100%)

The problem is that Hi power cannot be retained - they switch to mid power after about one second. I have tried this with three of them, and tried another LED just in case that was an issue. I first tried them after removing one of the chips to run at 700ms - but also tried one at the full 1050ma.

Whilst checking if any of the other three stars are connected to ground I found that the first star is connected - but with no visible link.
I then disconnected the third star and connected the fourth to try and achieve a two mode result - but the same issue occurs.:shakehead

Any advice please?

Have you try using a different battery, or recharging the one you are using?

It could also be that one of the 7135 chips is defective and going into thermal overload or something. At 700mA, if one regulator fails, it drops to 350mA, which would look very similar to Mid @ 30%. It could be that it's not dropping to mid, but that one regulator dies after about a second, possibly because of some internal short causing the somehow-still-functioning thermal protection of the chip to turn one of the chips off.

Maybe feel with your finger if one of the chips is getting hot?

In short: behavior is known, doesn't act like known/documented behavior -> consider it a defect. If it's one of the 7135 IC's, that should be easy enough to fix though.

Thanks very much chaps.

Her indoors had cleaned up my carefully laid out piles of stuff and I was using one of several batteries that had previously bench run my 501b conversions for over 90 minutes - and were awaiting recharge. :fail:

Please don't tell anyone about that. :shakehead