G&G Firehawk Motor / Gearbox Issue

[Connorthescot]

Hi all,

So I have had a G&G Firehawk passed on to me from a friend and unfortunately straight away I have ran into an issue.

Initially I hooked up a 1300 mAh 7.4v 20C LIPO and was getting zero trigger response on either full auto or semi.

Double checked that the battery was charged using a mutlimeter, and it was.

I then moved to the rear wiring loom going from the butstock out to the tamiya battery connector, the fuse connection looked slightly off so I have replaced this wiring and fuse.

Tried again with the battery and still nothing.

I have now taken the gearbox out of the lower and tried connecting the motor and battery up, and oddly I have had the motor function only once, which scared the crap out of me as I was just expecting it not to work.

So I have had a single rotation of the motor on semi and I cannot replicate that at all unfortunately.

I am thinking my next step is to open up the gearbox and check trigger contacts but I just want to get any advice before I go ahead and open this up.

Thanks,

 

[Shamal]

Have you looked at motor connections? 

 

[strykerles]

after it spun once did you check the fuse again?

 

[Connorthescot]

@Shamal - Motor connections physically look and feel okay. The connection from the lower gearbox onto the motors may be slightly on the looser side of things but still fit snug onto the positive and negatives of the motor.
@strykerles - Yeah, fuse is still in tact after it spun. When it did spin, I was moving the selector plate with my hand to see if I could engage the trigger contacts and connection must have been made somewhere. It was only a single very short spin, as it it was semi-auto.

Also, just for reference I have attached an image. If you need any other images to assist do just let me know.

[EDIT]

Looking at the photo below, I have actually just noticed a possible issue.

The positive and negative wires flip from the tamiya connectors i.e. red (positive) from battery then goes into black (negative) from the back of the wiring harness. Could that be the issue?

Thanks,

View attachment 92014

 

[strykerles]

dunno if it's my eyes but the wires look crossed at the tamiya connectors, black to red etc

 

[Connorthescot]

@strykerles - I just noticed that too actually.. is there any way to remedy this apart from fitting a brand new tamiya connector?

 

[strykerles]

you may beable to pull the pins out the tamiya connector and put them the right way

Did you get that connector from ebay? I brought one a while ago that had the same thing

 

[Connorthescot]

@strykerles - I just noticed that too actually.. is there any way to remedy this apart from fitting a brand new tamiya connector?

Sorry, double replies there - browser was being wierd!

Yes, unfortunately I think that is exactly the issue and yep it was from eBay! Reading quickly, looks like this is more for an RC setup and not airsoft.

Let me give it a bash mate and see how I get on, thanks for the assistance so far!

Managed to re-wire that tamiya connector to keep positive and negative the same throughout but still unfortunately getting nothing.

Heading out shortly so will try again in a bit.

 

[Rogerborg]

Good spot.  Yes, you can rewire Tamiya easily enough, you just need a precision flat bladed screwdriver or similar to push the tabs on the sides of the pins in.  We covered polarity and rewiring here.

 

[Adolf Hamster]

it's pretty typical to find airsoft and RC versions of tamiya connectors to have reversed polarity. haven't a bloody clue why airsoft manufacturers refused to follow the established precedent but that's what they've done.

if you have the polarity reversed then the motor will try to start backwards, which on the majority of aeg gearboxes is going to mean driving straight into the anti reversal latch. you'll typically hear a "click" from the motor when this happens. that in itself won't damage anything (that's what the arl is for) as long as you don't go holding the trigger down and dumping current through the motor. that won't stop the motor running when outside the gun though, it'll just run backwards.

assuming everything is going ok on the external connections, the next potential culprit especially for a gun with some rounds through it is the trigger contacts themselves being carboned up/burnt out. the fix for this is going to involve splitting the box to clean/replace them (depending on what the issue actually is).

 

[Connorthescot]

Thanks for all the responses so far, really appreciate it!
So with the polarity of the tamiya connector changes so the negative and positive is consistant, I am still getting nothing from the motor.

The fuse looks to still be intact too which was a suggestion from discord that trying to run the motor without the wires on the tamiya changes may have blown the fuse.

My gut feel is that I am now going to need to open up the box, first time for everything I suppose ?

 

[Floperator]

The Mini-Tamiya to XT60 adaptor I bought recently had its wires crossed - following the instructions Rogerborg posted above, it was literally a 2 minute job to swap them over.

 

[Connorthescot]

@Floperator - I managed to get the wires swapped around all good, unfortunately still no luck getting this motor turned over

 

[EDcase]

I got caught out by this too with a mini-Tamiya to Deans for testing new guns before converting to Deans.

It just made a click noise with the trigger pull.  And I thought ???  Luckily I know enough not to keep pulling the trigger if it doesn't cycle.

Was about to contact the store to tell them the gearbox was locked-up when I remembered a post about these stupid adaptor cables being wired for RC and needing changing.

Took literally one minute to swap the pins and all happy again.

@ConnorthescotSorry to hear that didn't fix it for you.  Can you rig some wires to touch the battery directly to the motor contacts?

 

[Lozart]

@Floperator - I managed to get the wires swapped around all good, unfortunately still no luck getting this motor turned over

Disconnect the motor and battery, check for continuity between the +ve battery connector terminal and the +ve motor wire when you pull the trigger. There's a lot of connections in there, I'd not be surprised if one of them isn't making good contact.

 

[Adolf Hamster]

My gut feel is that I am now going to need to open up the box, first time for everything I suppose ?

as @EDcase says worth seeing if you can rig up direct to the motor just to check the motor itself isn't dead, might as well eliminate all options before popping the box open.

make sure and keep a good hold of it (eg bench vice or some way to hold it solid) else it'll try and jump away on ye.

if you have to open the box then a couple of tips:

-use a screwdriver/similar pokey tool through the bolt hole above where the wires come out, that's the spring guide and holding it down (alongside fingers on the cylinder- the blue bit) will stop the worst of the sproinging when you split the gearbox halves.

-try and keep a good track on where the shims on the gears are, if you can make sure they don't go walkies (which they will absolutely try to do) it'll make re-assembly so much easier not having to re-shim it.

-when re-assembling, take care and don't force anything, use a pokey tool to make sure things like the axles on the gears line up with the bearings and if everything's properly in place it'll go together easy. if you have some decent magnets then they're great for holding the anti reversal latch in position for you.

 

[Fatboy40]

My gut feel is that I am now going to need to open up the box, first time for everything I suppose ?

... and pop in a GATE Titan whilst you're at it ?

(Best upgrade I ever made to my son's Firehawk, along with a MAXX trigger, it totally transformed it (no more jams on semi with cycle detection, really quick trigger response, so good with a little pre-cocking but in the end I disabled it as the stock motor got a bit toasty)

 

[Connorthescot]

I would love to pop in a GATE Titan or any mosfet into any of my systems but yet to dabble in it.
Next time though @Fatboy40!
 

Really just need to get this AEG working, messing about with it for ages.

I think I can jimmy rig some wires to test direct from battery to motor tonight, atleast that rules out the motor and then it comes down to any wiring issues in the gearbox and trigger contacts.

Tried a continuity check again a minute ago and I am getting nothing when testing the positive cables with the trigger pulled.

 

[Connorthescot]

So motor definitely works, direct battery to motor and it spun no issues.

Looks like a gearbox is being opened tonight - god give me strength! ?

 

[Fatboy40]

Looks like a gearbox is being opened tonight - god give me strength! ?

If none of the wires internally are damaged, so it may be the mechanical trigger unit at fault, you're welcome to have the one out of my son's gun for the price of the postage (I'm 99.9% certain I put it away safely with my other airsoft spare parts).