I’ve been struggling for some time now (2-3 weeks) to get my MTN-MAXlp HP build stable. I have already communicated directly with Richard around my issue, but I still don’t have a solution. It seems like Richard has had great success with this driver up to now. So, I’m taking a chance here, maybe somebody had a related issue.
My first driver build was fine. The only problem I had was that the mode switching was too slow, so I changed PLDN 19.1k to 4.7k. After this, the driver was great. I’ve configured it for 5.5 amps output running XM-L2 U4 - 4 modes, starting on Turbo. All was great, including the 478kcd!
I then built my 2nd driver, EXACTLY the way I’ve built the 1st one (including the same program). The issue now arose -> I could not switch/change modes. I only had max output, no matter how fast or slow I tried to change modes, no go. Just max output.
I then decided to build a 3rd driver. Once again, exactly the same build, the same program, the same issue! I then took this driver, reprogrammed it a few times setting a lower turbo mode, just to see if the driver will turn on at a lower amperage, which it did. The problem seems to be mode switching only, its start off at the correct mode. I’ve probably reflowed the MMU around 15 times during the diagnostic process, every time the same symptoms. I’ve replaced that MMU at the end with a fresh / new one (I’m so paranoid at the moment) - still the same issue.
I’ve fiddled around with the PLDN resistor going up & down with the resistance - did not help.
Has anybody experienced what I’m experiencing now? I’d very much appreciated any help.
Also, there is no way that there are that many bad boards, and I have been building them with boards from the same batch. I admit that I am a bit stumped as well.
I just assembled one of these today (3.5a w/guppydrv) and it works great. The timing is definitely different but not in a bad way. My problem is I can’t get it into configuration mode. If I tap to fast it never changes modes, to slow and it just cycles thru. M-L-Med-H. For me it’s fine the way it is but I can’t help but wonder what’s wrong?
Can you measure what pulldown resistor value you have? 19.1K or 36K? Sounds like I might have given you a 36K which is my preferred resistor for that driver, but with guppydrv you might need the 19.1K.
Finally had a chance to play with this today so I changed the pull-down resistor to 19.1k. I am still unable to enter configuration mode. When the 36k was on before I could have sworn it had 4 modes. ML-L-M-H. Now it’s 3 modes. It seems as if the timing is quicker than before. It still stays in 1 mode if you go to fast.
The timing, even with the correct resistor, is a bit tricky. You can't just tap the switch as fast as possible like on most drivers. There is sort of a rhythm to it. It usually takes me a few tries before I get it.
No I've done all I know to do but can't get into programming. The timing just isn't quick enough or something. I have been meaning to ask you if I should stack a 36k on there and try it.
I have been burning thru some primarys with it though. It's a 3.5 amp so in high it steps down in like 3 sec (with fresh batteries) but it's still more than 500lm and lasts a long time so I'm happy with that. That's not the way I intended to run it all the time but I just wanted to know how it would handle them. It gets really warm for the first 20 min or so but after that it's fine.
