FET problem in a MR02

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FET problem in a MR02


I've had some problems trying to get a 3 X 2 stack of 7317 fets in the MR02. That stupid black block box is right in the way, so it’s hard to see, much less solder. I think I'm not getting good connection on the fet next to the black box.

I may have shorted something out to begin with. The first time I turned it on, I was using a metal clamp to hold the PCB. That's one of the dumber things I've done, but I did it. I think it was touching Vcc and Grnd at the same time. Everything got pretty warm before I realized what I did, but I unclamped it and turned it off quickly. I think I still managed to fry something, because now I have this problem.

When I put the batteries in that fet stack heats up. It actually blew the fets the first time. But, a single stack of fets works just fine. I resoldered some new fet stacks and it started doing it again. I just put the last battery in for a second or so and felt the fets. The fets closest to the black box are still getting warm with the batteries in. Mind you, the car is turned off during this.

Is this a problem with the PCB or do I just need to get better connection with the fets to the board?
Cause I ride around town on my low-rider bicycle.

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