Why am I blowing 50 Amp fusses?!?!?

[HardCoil]

Yeah, and that's on stock AEGs I assume?

 

Once you start opgrading, power, and consequently current, will rise really fast (square function of the BB velocity).

[sadigh]

i think i know why its doin that mate, i had a similar problem with my p90.

 

its probably your bushings. when i replaced my bushings to metal ones, they were a bit tight and limited the movement of the gears, meaning that my motor had to work overtime to turn them. it made my gun battery go flat very quickly, made my motor smell a bit and made the fuse blow. i replaced the fuse with bigger ones each time, and they all blew. eventually i put the old businhgs in, added greese and now its fine.

 

have you dismantled your gun? check your gearbox, there maybe something obstructing the gears, maybe the anti - reversal latch?

 

hope this helps

[Xaccers]

i think i know why its doin that mate, i had a similar problem with my p90.

 

its probably your bushings. when i replaced my bushings to metal ones, they were a bit tight and limited the movement of the gears, meaning that my motor had to work overtime to turn them. it made my gun battery go flat very quickly, made my motor smell a bit and made the fuse blow. i replaced the fuse with bigger ones each time, and they all blew. eventually i put the old businhgs in, added greese and now its fine.

 

have you dismantled your gun? check your gearbox, there maybe something obstructing the gears, maybe the anti - reversal latch?

 

hope this helps

<{POST_SNAPBACK}>

 

Interesting, same thing happened when I put metal bushings in my P90, so now it's running on a mix of metal and plastic

[Shao14]

The MOS-FET transistor works as a swich instead of the normal copper trigger set inside the gun. A very low current is ran throug that, which in turn open and close the transistor, thus controlling the current to the motor. This is to avoid the normal copper switch causing lots of resistance, and in case of heavy upgrades, welding itself together (again... lots of Amps). Basically it's to avoid high current being run through a mecanical switch.

 

Systema also makes these for heavy upgrades.

<{POST_SNAPBACK}>

 

Interesting. You got the schematic for one of these relays, or is that proprietary?

[Hissing_Sid]

Is it the spindles that are tight in the bushes or are you guys too lazy to fit the correct shims?

 

[edit]

Shao: I've seen circuit diagrams for MOSFET trigger mechanisms around the net.

 

Don't forget, though, that you'll need more electronics to control semi-auto and full-auto as well as the actually switching transistor.

 

This will require you to fit electric switches to the fire-selector or selector plate, somehow, to select safe, semi and auto. Gonna make a right mess of your gearbox or, at least, make it a mess to fit.

[Xaccers]

Is it the spindles that are tight in the bushes

<{POST_SNAPBACK}>

 

Yes

[Hissing_Sid]

Yes

<{POST_SNAPBACK}>

Ewww...

 

I'd heard that P90 bushes were "tight" but the BS and half-truth that I've read seemed to suggest that this was actaully referring to how hard they were to put in.

 

Did you knock them in with a hammer?

 

Maybe you damaged the edge of the bush slightly?

Might be worth just dressing the edge of the bushes with a large drill, turned by hand, to remove any burrs from the edge of the hole.

Mind you, by now you'd think a burr would have worn off if it was a problem.

[Xaccers]

Wasn't just one sid

Some wouldn't even go on the spindles.

Upgraded ages ago, and I rarely use my P90 so I don't think it'll be a major problem (still running 8.4v with a 1J spring so probably a slower RoF than stock!)

 

I'm going to dig out my multimeter and find out what sort of ampage my MP5 is pushing as its still causing the fuse to blow on rapid semi-auto

[HardCoil]

Don't forget, though, that you'll need more electronics to control semi-auto and full-auto as well as the actually switching transistor.

 

Actually no you don't that's the clever part. You rig up the mos-fet to the normal switch in the box and put a small current through that. When you press the trigger, the switch closes, opening the MOS-FET which in turn feeds the motor. When you use the normal trigger system like this, all the semi auto controls and such work normally, just not directly on the motor. It's only when you want to remote control a box via a new switch that you run into problems with semi auto.

 

You just need the MOS-FET and a few protective components I think. I don't have the diagram and I do think it's propertary, he's spent a lot of time getting things just right.

[Hissing_Sid]

If you do that, what's the advantage of using the MOSFET?

 

Is it just to save wear on the trigger contacts?

[HardCoil]

As I understand it there are two reasons:

Less wear on the contacts (which can get substantial with heavier upgrades), and less resistance > Higher ROF.

 

Basically it's only worth looking into if you do have upgrades we can't discuss here, or if you want to do some crazy remote control projects

[Hissing_Sid]

As I understand it there are two reasons:

Less wear on the contacts (which can get substantial with heavier upgrades), and less resistance > Higher ROF.

<{POST_SNAPBACK}>

Guess what I spend this afternoon doing?

 

The trigger contacts on my ICS M4 died and I had to rip the whole lower gearbox to bits to clean them.

 

There's a coincidence, eh?

[HardCoil]

Haha that's life for you

[Shao14]

What's the "remote control" system?

 

I'll have to see the schematic to really understand what's going there. Anyone has any links on where I can find one of these? I tried to search for "trigger relay", and well, you can guess the result.

[HardCoil]

Remote control is where you bypass all the internal switch stuff in the gearbox and just have the transistor control power to the motor directly. You use that when you want to do some really weird stuff, like sentry guns. I did it in my gun to make a FAMAS box fire from a P90 trigger.

[Shao14]

Hehe, when you say remote control, I always think about that clicker thing for the TV.

 

But for a MOSFET to work properly, you need to bias the gate-source voltage and drain-source voltage accordingly to control the drain current flowing through the transistor. I assume in this remote control, you don't use any other power source, so you are using the power from the AEG battery, and you'll need at least a few more resistors or transistors for the bias circuit. Just wondering.