You sure it only has 12? That would mean each phase only has 4 FETs, only half of which are on at any one time (per coil end). The 80A has 18 FETs, 6 for each phase and 3 on (per coil end) at any one time. Granted, the 80A uses a different FET package, but the specs aren't that good on the 4833's... I would have thought the 150 would place FETs on both sides of the power board. :neutral:

Well to be really honest. I had to use very creative lighting to even see it (I now understand your statement). On the one side of the board there were two rows of 6...maybe there were more directly underneath the heatsink somewhere else... There was some kind of power chip on the bec side +-"KIA78D05" it looked like. I did not want to unsolder the connector and probe any further. So maybe there were more...mmm. BTW: The electrolytic caps were 1000uf x 3 ... The exact chip number was 4833N R836. The microcontroller number was filed off.

I'll take a look tommorrow again. Could be 14 or 16, but definitely not 18 on the side I was looking at.

On the 80A, the FETs are between the power board and the brain board. The heatsink just touches the PCB, but no FETs directly.

BTW: The uP might simply be a PIC, so it wouldn't really matter if you could read the part # or not since those chips can be pretty much whatever they are programmed to be.

Just because I'm such a nice guy I went to look again, took it apart. There are TWO banks of 6 FETS on the other side of the brain board. Thats makes a grand total of 12 as I said before. Did not take the heatsink off(think they glued it). BTW: The semi transparent bottom part is not sealed well - i dont know why they bothered with the rubber seal because there is a large hole in an obvious place.

I don't get it, so the 150A and the 80A has the same MOSFETs!!! Do you have pictures of the MOSFET board of the 150A?

No, the 80A has 18 FETs, and they are different part numbers too. This is what leads me to believe there is an extra 12 FETs under the heatsink that is glued down in the 150A...

page 3 of this thread:rules:

Yeah, page 3 clearly shows the 12 FETs under the heatsink. I think there is an extra 12 sandwiched between the brains board and the power board, like there is with the 80A. That would give the 150A 24 FETs, which would make MUCH more sense...

there more(about 12) fet's underthe second board
so i can take a picture to show you the gut's

Ok, my fault. The 80A has the DPAK style MOSFETs and the 150A has the same MOSFETs as the Tekin R1/RS and maybe the Mamba Max and Mamba Monster. I apologize for my mistake.

The 150A uses 36 MOSFETs, ON semi's NTMFS4833N(the MMM uses NTMFS4108N).
Here's my picture.
On the top side of PCB: 4x6 = 24 FETs，there are two more rows underneath the power PCB, 2x6 = 12 FETs. Note the way the heatsink touches. Looks like HobbyWing was trying to cool the PCB, not directly the FETs (to take care of the ones on back side maybe? ).

http://www.rc-monster.com/forum/atta...1&d=1236230469

Very nice......matches the MMM.

Now that makes more sense. 36 of those FETs more than meets the 150A spec. Those metal bars attached to the PCB is a good idea IMO because the PCB carries the majority of the heat (heat doesn't travel as well through the plastic FET casing as it does through the leads).

How did you get the heatsink off? I tried, but couldn't.

Yes, the metal bars act as a heat transfer, as well as a current flew path, a smart design.