Mosfet Issue - full auto on power up

[ManateeMatt]

Good good, that makes me happy.

[Stealth]

Oh WHELLLLL then.

That explains some "botched" installs where users reported firing on auto without trigger being pulled but no physical damage to the FET itself.

Learn something new everyday.

[venture]

PM reply sent to you stealth.

As you say "learn something everyday". I know Matt must have been very patient trying to troubleshoot this problem. Nice job, though. That should help things on your end, Stealth.

[venture]

What I don't like is the labeling in the manual diagram. I am not an electician, however, and it is probably the correct way to do it.

They label the negative wire to the battery "3" and the negative wire to the motor as "3" with a superscript "1" or maybe it was " 3' ". This led me to believe that it did not matter which way to attach them.

If battery lead was "3" and motor lead was "4" or something, then I would have taken note of the positioning of those wires as they must be separate leads because the numbers are different. But, as I say, I am not an electrician. Maybe someone with better knowlege could teach me the proper conventions and their meanings.

[Kos-Mos]

Proper wiring diagram should use symbols, not numbers. So it might just be a typo (or refering to steps in the instructions).

[Stealth]

John here:

From my experience the manual is correct.

When soldering the negative leads, make sure that the contact patch with the 3 transistor prongs is connected to the negative battery terminal.

The other contact patch on the opposite side closest to the heat sink of the FET should be connected to the negative motor terminal.

[Ron-E]

I had an issue with that same fet, Stealth sent me a replacement no questions asked. Stealth, I was wondering...did you get a chance to test it out?

[Kos-Mos]

You can test FET chips with a simple multimeter.
Set on DIODE mode, and have the positive/red lead on the motor tab, the negative/black on the battery tab. It should NOT beep/contact (OL on the display).

[Stealth]

Haven't had a chance to physically wire it up but I was testing with a multimeter as Kos described.

Without anything plugged in or wired the resistance between the two negative contact patches was 0.1ohms. This tells me it's in the closed position and the MOSFET is broken.

[Rabbit]

Interesting..I just had this same issue myself with the PicoSSR2..now im second guessing my install.

I followed these instructions:



Edit: It does raise my curiosity though that we were all using the same unit and experienced the same issue.

[ThunderCactus]

Or it could be they're just freaking tiny and aren't designed to run anything more than a stock marui?

[Stealth]

Yes and no.
John has one running on an M170 build, Lonex A1 an 11.1 lipo.
I've got a few running some relatively milder (~400fps) builds, all of them have been used for over a full season.

It's not the voltage or amperage that kills them, most of the time it's either installer error and/or inductive loads of the system, and that's near impossible to predict.

[Stealth]

Just noticed that the wondeful image that Matt put up is actually backwards now for the PicoSSR2. They have reversed the FET.

[ccyg8774]

Got a little confused so went back to check the manual.

This is SSR.


This is SSR 2.

I didn't notice there is a difference, as I only been using SSR 2 before... I think it would be good to have some marks on the circuit board to label the soldering spots.
I mean, didn't notice there is a difference (wasn't aware) before today.

[Stealth]

Originally Posted by ccyg8774

Got a little confused so went back to check the manual.

This is SSR.


This is SSR 2.

I didn't notice there is a difference, as I only been using SSR 2 before... I think it would be good to have some marks on the circuit board to label the coldering spots.

Look closely...