CYMA AKMS intermittent problem

ordinaryfella

Hi Everyone,

My Cyma AKMS has been acting very strange recently.

In the middle of a game it would stop firing, ie you would pull the trigger and nothing would happen no motor sound or anything. Sometimes switching to full-auto and holding the trigger in would make it start firing again(although last time this didn't work).

In the safe zone if you removed the disconnected the battery and re-connected it would start to work.

So can rule out flat battery.

Thinking it maybe the trigger contact or perhaps the wiring form the battery connector in the gun, but wondering if anyone has any ideas?

Thanks for looking.

thermo

sounds like the trigger contacts are dirty.

Untamedlemon

ordinaryfella wrote: »

Hi Everyone,

My Cyma AKMS has been acting very strange recently.

In the middle of a game it would stop firing, ie you would pull the trigger and nothing would happen no motor sound or anything. Sometimes switching to full-auto and holding the trigger in would make it start firing again(although last time this didn't work).

In the safe zone if you removed the disconnected the battery and re-connected it would start to work.

So can rule out flat battery.

Thinking it maybe the trigger contact or perhaps the wiring form the battery connector in the gun, but wondering if anyone has any ideas?

Thanks for looking.

It could be that your trigger contacts are dirty from the two copper parts constantly making contact or a if your using tamiya connectors thy could on their way out. You could just open up your gearbox and give the contacts a wipe down and it would be no harm to clean and regrease the rest of the gearbox as well.
As for the Tamiya connectors, if you've been using them quite a lot then you probably need new ones. When you do get new connectors get deans connectors(T plugs) instead of Tamiya connectors. They have far less resistance and will slightly increase rate of fire. In saying that I still haven't made the switch simply because I'm busy but really need to soon (ie. I'm being lazy!!)

Or what thermo said is far simpler than my paragraph, I really have to shorten my explanations!!

ordinaryfella

Cool cheers guys. Will do this over the weekend. Also ordered some deans connectors with a mosfet.

Thanks for the help

Southern Dandy

How old is the gun, and are you using lipos?.

I would not rule out a mechanical cause either but at least once you have done what the two lads have mentioned above you have ruled out most of the electrical causes of your problem.

ordinaryfella

I normally use nicd but planning to permanently switch to lipo once the deans connectors arrive which could be a week or two. Last time the issue happened a lipo was in it.

The gun is fairly old. 3 years maybe. Although it hasn't seen massive use because i've only recently got back into airsoft.

Cheers for the help everyone.

Untamedlemon

ordinaryfella wrote: »

I normally use nicd but planning to permanently switch to lipo once the deans connectors arrive which could be a week or two. Last time the issue happened a lipo was in it.

The gun is fairly old. 3 years maybe. Although it hasn't seen massive use because i've only recently got back into airsoft.

Cheers for the help everyone.

Are you sure its nicd. It might be nimh and if it is id recommend that you stay with nimh. Deans dont automatically make your gun 'lipo ready' so to speak. Lipo will seriously fry up your contacts and since its cyma and its 3 years old a lipo will destroy your gearbox in no time. Id recommend that you just switch or stay with nimh to avoid breaking your gearbox

Also lipos are pretty dangerous if not handled correctly so make sure that you know what your doing especially when your changing the connectors to deans cause if they tip off eachother youll have a serious problem

ordinaryfella

sorry nimh(i blame the sun).

i would of thought a 7.4 lipo would be similar to 9.6 nimh in terms of wear on the gearbox( I know other things come into play here, but as a rough guide).

Also I thought lipo in conjunction with a mosfet are for healthier for your contacts.

When the aeg is in the humor to shoot it does cycle fine, for what that's worth.

Cheers for the reply

Southern Dandy

7.4v lipos are fine imo, 11.1v on the other hand are just nuts.

And yes they are better paired with a mosfet for your trigger contacts amongst other things depending on the brand of mosfet and what it offers.

People always say Lipo's are dangerous but I honestly can't see why provided you look after your and periodically inspect them for damage, nicks, etc, and ensuring they are charged/dis-charged with the appropriate charger and are never left drop below 3volts you should never have a problem with them. Same as any battery to be honest, if lithium batteries were not safe we would have them in laptops, phones and all that.

ordinaryfella

11.1v are nuts alright.

Probably be a week or two before i can get a good luck at this, but thanks everone