RMM i hope you will stock some mosfets for this light, it will be very good to have an option to buy them from your store, instead of endless searching on mouser site.
I think I may try the 70N02 and try for 6.5A-7A with the stock driver. If it blows I guess I'll have a $150 paperweight, huh? Nah, that will just motivate me to try my 7A-8A option... 
The driver should take it i think, with replaced mosfets at least? but i’m noob so don’t count on me lol 
If 5,8A is peak. Im already headed for my 7-8A option.
But I could try 70N02 first. Just replace/remove "C001" from Q1 and connect the 70N02 in similar fashion + further resistor mod? I can try that if you want. But if you are going to do it anyway, I could just sit back and relax get some progress done on my scratch build.
Racer, I'll let you try it first! I'm pretty busy today. I would keep the resistors the same to start with and see how the current compares. I think that at a certain point we're really going to need a larger inductor, more input capacitance, etc. to make this reliable.
As a very quick and temporary test I connected the 70N02 like this:
Did not get over 1 amp output. Did I connect the legs in the wrong way or something?
Changed back to stock mosfet and saw 4,8A at the emitter. No harm done.
No, that's the correct way. The gate charge, PWM frequency, etc. may not be suited for the 70N02. I guess we'll have to stick with stacked "tiny" FETs for now. BTW I have run this one quite a bit more and it's holding up well. I feel confident with it around 6A.
So with the parts swapped, 5.5/6A should not be a problem right?
It hasn't been so far. That doesn't give a 100% guarantee down the road, but I feel pretty confident in it now after some fairly significant testing.
Oh i’m pretty sure it will be fine
I never run more then 1/2 mins on turbo - outdoors 
Thank so much guys for sharing this great info!
Bah...nevermind. Just realised that RaceR already tried the same basic thing in post #88. Guess it's time to order up some of the smaller ones from mouser. 
Hey guys, I don't have any of the tiny mosfets but could you use this voltage regulator instead of the stacked minis?
http://www.radioshack.com/product/index.jsp?productId=2062599
I actually have a few of these in the basement and if they will work it'd be great. They also have the added benefit of being able to shed more heat.
Hi guys, can anyone tell me exactly what transistors and resistors should be swap?
i got the same transistors which vinhn used for his TK61.
How do you guys solder these resistors on? I was told at the local electronic store if I use a soldering iron it will fry the resistor. They said I need some kind of special heat gun?
Welcome to the twilight zone. Its called a hot air rework station I believe. But its not required. The guys (and gals) here have been doing it with soldering irons for ages. They do so daily. They dont just solder them on to new boards, they stack them.
Maybe someone should tell them they cant do it.
A youtube clip from this thread… soldering resistors
http://www.youtube.com/watch?feature=player_embedded&v=214kSNaBD3A
Lol of course you can hand solder the resistors. The same temperature is needed using hot air to melt the solder as is needed from the tip of your iron, the only difference is the source of the heat.
Well I guess with a steady enough hand I could do it maybe after a beer it would be easier. One more quick question. I am planning on doing the tk61 resistor mod with the R030 resistor but can’t seem to find any that look like the picture. Is that 30ohms or 30mohms?
Well, I’m an idiot just figured out its .030 ohms right?
Welcome to the forum jcminar. You're correct, .03 ohms. The "R" is the equivalent of a decimal point.
Where can I find these .030 ohm resistors what’s the watt on these things people keep asking me. And would a .028 or .033 be ok?
There are a few options on these, so it can get a bit complicated to those of us that aren’t into electronics. The package size is important, it determines how long and wide the resistor is. I once ordered some that were backwards, wide instead of long. It was relatively easy to make it work but it covered the entire stack of 3 normal resistors to do so.
I still haven’t figured out how important the wattage rating is, I usually go for the higher rating but don’t know if it’s necessary.
.028 or .033 should be fine, very close to the .030 you’re looking at and as such would make a very small difference, probably only measurable and not noticeable to the eye.
I intend to try an R025.
I used an online resistor calculator to figure out the end resistance when stacking…the 2 R050 give a net of .25, with an R030 on top of 2 R050 the net result is 13.63636364, with an R025 instead, it would be 12.5. By going with 2 R030’s the net went down to 9.375 and if 2 R025’s were used it would be 8.33. So I’m thinking it should handle the R025 ok, but not 2 of em.
My primary reason for using the R025 is because I already have some. Should know how it works in the next hour or so, as my light is due in today.
DigiKey or Mouser are likely places here in the states.