Hooked the PWM up the the 303 resistor like you did since that was the last place I had it when I found the error.
PWM whine does not come from ground.
Glad to hear you got it going. I guess I need take some pictures of a proper connection. I tried to explain in Post 52 that the pictures that the wire was not connected to the correct pin, but the "B" marking was where to connect.
Wight,
I have to disagree with you about epoxy being superior to clay in deadening sound. I use to build speakers and clay is an excellent material for helping preventing reflections that cause standing waves and such within a speaker enclosure. It absorbs sound waves (higher frequencies) and vibrations very well. I'm not claiming to be an expert, but epoxy is much harder and more likely to transmit vibration.
You could be right. I recommended epoxy based on it’s lower viscosity. My logic was that a lower viscosity would allow the epoxy to better conform to everything. Epoxy is normally used for potting electronics of all types. I assumed that if we could limit the movement of the stuff that whines then there wouldn’t be any noise to deaden in the way that you describe.
I’m quite sure about the lower viscosity being an asset for thermal potting, but I’m definitely not sure about the noise part.
And I should also say that you could be right. My recipe will press into almost all the small crevices with ease, but it probably won't get under a component (where as epoxy may get pulled under by capillary action). Your really need to play with the stuff to appreciate it. I should note that it is very difficult to remove it from those small crevices.
I need to try that recipe anyway. You’re still using the Duct Seal version, right? I’ve added that to my shopping list for the next time I go to town.
Yes, that particular duct seal that is specified in the thread. I wouldn't substitute oil based clays. In my experience, oil based clays liquify when they get too warm. I don't know what that duct seal is made of. It seems like an oil base clay, but it doesn't run when it get hot.
I still do not know what MCU is in use. A similar looking MCU (similar grinding, similar white dot) is used in two Eagle Eye drivers as well:
Eagle Eye X6
Review: Eagle eye X6 UPDATED: Lumens & lux after driver mod and heat handling (scroll to nearly the bottom of post #1)
Eagle Eye X2
what kind of driver is this (from Eagle Eye X2), and can I get a bit more current out of it?
Note that djozz shows slightly different markings from what was on RaceR86’s driver. From what I can see it’s an open circle and a filled circle? (and of course also the big dimple, I’m not talking about that)
Taking pictures of the front and back of 2 of those MCU's. Should post them in a few minutes.
Bottom MCU upside down (That is an "H06" with a dot over the "H"):
Top MCU upside down: Appears to say "A10"
Mine had 2 R068 sense resistors and I blew several XM-L2’s at Turbo. Worked fine in the lower modes but Turbo turned it Off. Poof!
I looked to the star, the thermal path on mine was a bit low so I used solder paste to fill it and got an XM-L2 working at 7.15A. But I coudn’t get it to throw like the current indicated it should. So I tried to put a different resistor on it. Poof! I mean as soon as Turbo is selected it simply goes off, then the emitter is dead.
So I did the math on the sense resistors. Stock the resistance is .034 or thereabouts (not at my desk) So I pulled one of the R068 and stacked 2 R200 there for .040 total. This got me 4.83A at the emitter and all was well. Only I was getting lower output of course. And I didn’t get this TK61 to do 150Kcd. So I did some more math and decided to use an R140 in place of one R200 for some .037 total resistance. Poof!
Getting realllllly tired of poof!
So I pulled the star, put a copper Comex star with a Luminus SST-50 on it. The 20mm star is too small of course, so I cut a disc of copper at a similar thickness and put it under the Comex, my new disc is maybe 30mm. Just fits between the lead holes. Then I stacked a second R140 on top of the R200/R140 stack. So now my total resistance should be less, at around .027 or so. The Luminus is getting 5.60A measured between the pack and the driver. (The 7A reading was actual emitter amperage, taken from a loop soldered into the neg lead with my clamp meter)
It works, works pretty well actually, and is doing 162Kcd or so (again, I don’t have actual numbers here as I’m on a different computer and not at my desk with all my notes) But pulling the dome off the SST-50 didn’t net the throw gains normally associated with the Cree emitters.
I have one of the new Noctigon 35mm copper stars on the way. I plan to try a de-domed XP-L here and see where that goes. I need to get new sense resistors as I don’t trust the R068 I pulled off. Might just get the next step up from that as well in an effort to lower amperage a bit.
FWIW, I used a Qlite board that was totally stripped…put a new ATiny13A with Star firmware on it, used the resistors as usual but no regulators. I did a Zener mod so that the ATiny13A can get power directly through the board. If you’ll notice the via with a pad in the lower right hand quadrant, beside a cap, above the 151 resistor, that’s where I got power for the ATiny13A.
I used it a fair amount at 7.15A, the 5 modes worked well, low was quite low (no notes here) but I couldn’t get focus where I wanted it and the best throw I got was just over 500Kcd (yeah yeah, my memory sucks…might have been 555Kcd but not sure) So yeah, I screwed it up but plan on making it rock again. 
What cell configuration are you using Dale? Sounds like you may be feeding too much power to the Attiny and then it's transmitting too much voltage in the PWM signal to the HX-1175.
Where are you connecting the PWM into on the board? The same spot you spoke of in Post 70 above?
EDIT:
I recommend you power the attiny from the pad with an "X" below. The pad between the MCU and the yellow component labeled "226A, 90HF1". I don't know if you need to take off the zener mod.
When I make any changes at all I put the light completely back together to test it, save for leaving the reflector out in order to clamp the meter on the wire loop at the emitter (most of the time)
So the power supply is the battery carrier in the TK61. I have 4 Panasonic NCR18650B 3400mAh cells in it. I’ve also got the extension tube with 4 more but don’t use that when testing.
And yes, I connected pwm at the MCU side of the 30,000 resistor, just off the pwm leg of the mcu (mcu removed of course) so I’m bringing the pwm back in where it was originally coming from…the signal then goes through the 2 resistors on the way to the controller just as it was originally set up.
With the Zener mod to the Qlite board, the MCU cannot get over 4.5V. Works on a dozen or more drivers I’ve built for MT-G2’s so it should work here, right?
Hopefully, someone that knows a lot more than me can help you. I'm wondering if the zener is not adequately bringing down the voltage to the Attiny.
buying an SBT-70 and putting it in this TK61, letting the power fly. 
Ultimate throw be damned (I’ve already got 617Kcd in another light)
attiny13 just stops working if voltage goes over 6v. Besides, whatever component is getting the PWM signal operates from a digital signal (either on, or off) so more voltage or less voltage on the PWM pin should have no effect on the output. 6 volts is just as 'on' as 4 volts.
I don’t think this is the case. Comfy’s explanation is correct, a higher voltage on the buck controller’s PWM input will not cause the problem DBCstm described.
It’s more likely that the driver produces high voltage spikes at higher currents. We have that problem with other drivers as well. The “big” LEDs seem to cope with this better than the XM-L/L2.
I did think that the hx-1175b was shown to work OK driving an XM- series LED at higher currents than that though… Am I remembering wrong?
I thought some buck controllers do relative voltage adjustment.
Are you two talking generalities, or about this specific buck controller? If generalities, do you feel 100% certain that it's safe to rule out the PWM voltage as the potential issue?
“generalities” puts a negative spin on what we are saying. We are telling you how all PWM inputs work.
The only thing a PWM signal communicates is “high” or “low” (two states, like zero and one).
Not trying to cast dispersions on what you 2 are saying. Just trying to figure out what we know for certain in order to figure out how to help Dale.
The driver seems stable, but I have not used an oscilloscope or anything to search for spikes. Given no other options at the moment, I think Dale should grab the voltage from the point I recommend he use in Post 82 and see what happens.