Gate Merf 3.2 not working correctly? F2000 semi-auto trigger not working

[RostokMcSpoons]

In preparation for a couple of new 11.1v batteries arriving for my F2000 (already upgraded with full cylinder, hi torque motor, better spring), I've bought and installed a Gate Merf 3.2

I've taken the front (left) trigger wire and moved it to the connect at the rear contact, and installed the single signal wire to the now open contact.

I've programmed the MOSFET for the 11.1v LiPo battery, but everything else is at the defaults.

 

It fired.  It fired full auto at 19rps. Nice'n'snappy
And then it stopped. 

 

I took it all apart again.  Put in the new piston which I'd already found has less of an airseal, but had the correct piston head to go with my new cylinder head. 

And then it fired again.

And then it stopped.  Recharged the battery (from 10% charge, 3.60v each cell, which didn't exactly scream 'battery voltage too low' to me)

And then it fired again.

And then it really jammed up.  Might be my fault, maybe I didn't tighten up the screw enough but the piston head came away and broke the rack.  

I took it all apart again.  Refitted the old piston.  Radiused the gearbox shell too.

And then it fired again.

And then it stopped.

 

It always fires with the programming trigger connected, but when I go back to the signal wire / gun trigger, it doesn't always fire again.
The signal wire looks fine, no obvious pinches on it, the solder is secure.

The fact it has sometimes fired again after a delay makes me think of a thermal cut-out, but everything has only got slightly warm after the few bursts I get to fire each time.

 

I guess I'll re-solder the signal wire, but is there anything inside the trigger unit that might have gone awry too?

Edited February 8, 2022 by RostokMcSpoons
Changed topic title (again)

[Iceni]

Your wires should look like this. Cut on the white crosses.

 

Quote

I've taken the front (left) trigger wire and moved it to the connect at the rear contact, and installed the single signal wire to the now open contact.

I think what you've done is use the signal wire to carry full current, hence it shutdown.

The diagram above with the double signal wire directly to what is now an isolated contacts circuit.

The motor directly to the Deans, as an isolated motor circuit.

If it's still working on the program button then you should still be good.

There was no need to move any wires at all. Damn I wish you would of just asked for a diagram before you started.

 

Edited February 5, 2022 by Iceni

[RostokMcSpoons]

Thanks Iceni, I'll consider what you have shown, but my method is as per the Gate instructions...

 

https://www.gatee.eu/images/gate/instrukcje/merf32-en.pdf

 

Section 2a, which specifically says the signal wire only carries a small current

[Adolf Hamster]

it's possible @Iceni's theory about the wiring being off is maybe happening.

 

normally with the gate mosfets i find it much easier to use the 2-wire setup (as in @Iceni's drawing) than try and muddle through the single wire setup, although bearing in mind the pic is the g&g v6 box rather than the cyma v3, but the same general idea just the contacts are in different locations.

[RostokMcSpoons]

I think I'd end up having to splice wires... basically I thought the simplified version with the single signal wire would be much easier to reverse (if I had to) than messing with the current wiring...
and in fact the instructions mention the second option when replacing all the current wiring with a heavier gauge.  

 

 

However... it's not working.  So I either reverse it and find a 7.4v battery that'll fit (having just requested an 11,1v nunchuck from Titan which won't fit, whereas the original 7.4v did, d'oh!) ... or I fix this.
I'm not entirely sure I'm brave enough to strip off what's there.

 

Edited February 13 by RostokMcSpoons

[Adolf Hamster]

personally, i'd go with the 2-wire setup.

 

iirc they give you plenty of wire with the 2 sets of connectors, enough to trim a length off to bridge the semi and auto connectors (if not, lemme know, mans probably has some lying around somewhere)

 

then run the heavy gauge direct from the mosfet to the motor (only place it's needed), basically the 2 motor spades going into the same deans plug which then goes to the mosfet.

[RostokMcSpoons]

They give you the connectors, and the two sets of signal wires (one single, one double) are both very long, but no heavy duty wire.
I could butcher some of my existing tamiya leads etc to harvest some.   

I don't have any spade connectors so I'd have to splice onto the rather short bit of red wire coming off the motor... which just feels like another potential point of failure, but I guess it's what I'm left with.

 

Ok. I have a plan of attack for tomorrow.  Now I'm off to the pub!

[Adolf Hamster]

the light wire is fine for the majority of the wiring going from the mosfet and across the 2 sets of contacts.

 

you'd only need enough heavy gauge wire to go from the motor to wherever the mosfet is going to be, for example the one terminal already going to the deans connector from the motor won't need touched, just trim the other wire coming from that deans and plug it straight into the motor.

 

something like this:

 

remove the green-traced wire entirely, cut the black striped wire where the green X is and solder it (black line) to the motor spade (or the the motor, if you feel so inclined)

 

your other 2 red wires you could leave as-is, personally i'd swap them for the light-gauge wire for the sake of neatness but that's up to you.

 

 

edit:

 

some top tier mspaint skills later:

 

so wiring wise:

1 has light wire going to the smaller mosfet connector, and to point 5 (which one doesn't matter)

 

2 has light wire going to the smaller mosfet connector and to point 6 (which one doesn't matter, as long as it's not connected to 1 or 5)

 

points 3&4 are wired with heavy wire to the mosfet deans connector (with polarity matched for the right motor direction), like the above pic.

[Iceni]

Dude it's the same as the AUG.

The single wire system only works when you have a single set of contacts, like a regular V2, V3 (AK). As soon as you have a secondary set of contacts the method I put above is the easiest way. 2 cut's and just run 2 separate loops.

It's actually on the same page as the V2 diagram, Under it... Figure 3 page 11 of the manual.


You don't need the motor spade connectors. Your putting a deans in and the motor is separate from the loom because of that. So provided you make sure you can get the motor out of the cage with the wires on (you can on an AUG, not sure about the F2000) then you can just solder the wires directly to the motor.
 

 

 

 

Those are pictures I did for another fet but it's the same diagram for the merf.

In addition to this you also have to put one of those single shot trigger back to normal.


Looking at how you've wired it I don't think you have put any power down the signal wire.

But it would only work in single shot, and full auto would cause the Mosfet to power down thinking it had a short circuit. So exactly what you saw. As the single shot trigger would initiate the motor, the full auto contact would be open, but there would be no signal wire signal as the COL would have broken the  semi contacts. So it would kind of fall over itself and go safe.

 

 

 

 

A single wire setup would look like this. Had to have a good think as to how it would work.
 

Edited February 6, 2022 by Iceni

[RostokMcSpoons]

Ok, after a nice night in the pub and a good sleep, I'm back.

Thank you both for the diagrams...

I like to think that, self-deprecating humour aside, I'm a reasonably intelligent man, but I think I have a blind-spot for electricals and electronics, and so I'm going to ask for some step-by-step confirmation of what to do.  And in this case, quite literally, the blind-spot is what to do on the underside of the gearbox.

Do I need to clear both the trigger contacts, to fit the double signal wire?

 

Or do I re-connect one of the existing wires to the front connection, so it's back to how it used to be?

 

 

 

[Iceni]

1. Remove signal wire.

2. Move front trigger wire back to original position.

3. Cut the + and - wires as per this diagram.

 

4. make a decision - You can go with the double signal wire. Solder it to the green area wire tags. Preferred method. Polarity doesn't matter as this circuit is now isolated from the mains. The sensor wire can go any way into the Merf.

4.b. Go with a single wire as per the last diagram I posted above - note you will have to work out how to feed the + side of the trigger. Polarity is important. The feed from the + is essential and the sensor wire has an orientation on the Merf.

5. Connect the deans directly to the motor.

Edited February 6, 2022 by Iceni

[RostokMcSpoons]

First step done...

 

Cutting the two wires below the tags now...  (this is the nearest I'll ever get to Mission Impossible...)

Do I just cut them as near to the tags as possible?  I did try to de-solder from the tags, but the solder just won't melt
 

 

So...

• The yellow crosses are cut
• The yellow lead is discarded
• The black/red is redirected to the motor (green)
• The signal wires (purple) are soldered to the tags

 

...?

Edited February 6, 2022 by RostokMcSpoons

[Iceni]

Yup cut on the yellow crosses.

Yellow tag wire can be discarded.

Deans directly to the motor with some wire, I often just solder directly to the motor with that gearbox as the cage can be removed with the wires on.

 

Purple to the signal wire.

[RostokMcSpoons]

[RostokMcSpoons]

 

 

Oh dear.

It does shoot, and doesn't stop like it did before.  

But single-shot still doesn't work correctly.  I sometimes I get single shots, but more often I get bursts of shots (and yes, I checked the settings to make it's set to single/auto)

 

Here's how it's set up now:

 

I can only try moving the signal wires to the front contacts, can't I?

(Edit: no, that's no different electrically than what I've got now)

 

Maybe I ask Gate tech support tomorrow

 

Edited August 18, 2023 by RostokMcSpoons

[Iceni]

before you do anything.

Pop a piece of tape over the plate on the trigger style contact... You may have just lifted the auto fire pins

 

With the tape in place you should just get semi.

Provided that works. the next step is to just lower one of the little contacts on the inside of the trigger/auto contacts until semi and auto are separate again.  Adjust only 1 pin.

Edited February 6, 2022 by Iceni

[RostokMcSpoons]

Nope. 

It's odd.  I move the trigger gently and slowly back, I'll get one or two or three shots.   Yank it back and even with electrical tape or paper blocking the contact it'll run full-auto until I release the trigger

[Iceni]

If the tape isnt working then the problem is probably with the semi auto contacts. You might have nipped them up a little with the heat and it's holding the dolly.

You should be able to see the dolly resetting when you cycle the gearbox.

I need to head out for a bit - will be back in 1 hour ish.

Edited February 6, 2022 by Iceni

[RostokMcSpoons]

 

In spite of appearances, the trigger contact isn't quite hitting the other one, so this was a successful single shot.

I presume your talking about the arrowed piece?

So yeah when it works I can see it push up.  When it doesn't the thing shuttles back and forth like a loom loon

 

Are you saying something's gone out askew on treadle?  This is a possibility.   Back when I was first trying to put this gearbox back together, I had terrible trouble with the plastic trunnion on the lower side of the gearbox, it'd slip from it's locating position on the gearbox and push the tappet plate up and out of position.  I tracked the problem down to a missing grub screw... not having one to hand I used a bent nail through the hole to hold it place... 

 

 

I could take the gearbox apart to ensure it's still correctly located, but I'd expect it to bind altogether if it had moved out of position again.

But if you think it's worth a look, I will

[Iceni]

It shouldn't just push up. It should push up and snap back to the starting position without needing to reset the trigger. On semi auto.

So with the tape over the auto contacts -

A single full trigger pull -

Moves the dolly forwards - It touches the contacts.
COL hit's the dolly lifting it over the trigger - dolly snaps back - And it falls back into the reset position with no contacts been touched on some trigger designs it might stay at an angle but it should always snap back.

Trigger is released and lifts the dolly and picks up the step that will allow the trigger to be pulled again.


If the Mosfet is working on the program trigger, and is working in AUTO then the only fault that can be left is the Semi auto contacts and Dolly.

That whole assembly is the same as the AK. So getting a replacement is easy enough if need be. But I don't think this issue is the MOSFET if the program trigger is working as intended, as all that trigger is, is a push switch.

Edited February 6, 2022 by Iceni

[RostokMcSpoons]

I've taken it apart again and checked:
The plastic trunnion was correctly located into the gearbox shell.

The dolly seems to move freely back and forth against the spring pressure. 

My pic shows it elevated but that's it's natural backwards position.

Pulling the trigger moves it forwards and slightly upwards.

 

I don't know, but it all looks the same to me as it's done before (when it worked, pre-MOSFET)

 

I'll ask the Gate tech support if they've seen anything similar

 

Edit: Set up a support ticket with Gate this morning, let's see if they have any ideas.   I referenced this thread, so y'all be on your best behaviour, y'hear!

Edited February 7, 2022 by RostokMcSpoons

[RostokMcSpoons]

(Probably 'bad form' to bump my own thread after I replied last, but 'what the heck')

Stripped the gearbox down to take a close look at the trigger contacts. and check alignment of everything.  The contacts on the dolly looked like they were touching the front contacts on one side, so I widened the gap slightly so only when the dolly moved forward would it contact either of the sprung arms... somewhat like this pic nicked off t'web...

(actually the main contact goes much further forward between the two arms when the trigger is pulled)

 

I thought that might fix it.  

It didn't.  

I've just tried setting the FET to do SEMI/SEMI as the firing options, but the darned thing only does SEMI/BURST so I can't use it on site unless I sort it
Having it on SEMI/BURST, it does do the three rounds properly, but can still do it even with the full-auto contacts blocked with a piece of paper.

 

@ak2m4 is there any mileage in ordering a replacement trigger unit, do you think?

I'm also still waiting on a proper reply from Gate, though they've acknowledged my ticket has been raised.

Edit: They just did. 
First step is they want me to solder the signal wires directly to the front contacts. 
"It seams that the problem is with the trigger contacts. F2000 is a rare replica and honestly we do not have one in our armory but we will try to help you as much as we can. In first step we would recommend to desolder these wires on the photo and then solder only signal wires from Merf directly to the gearbox trigger contacts and check if the semi-fire mode works as it should."
 I could point out that's electrically no different but I guess I'll just go ahead and do it anyway.  Then I'll ask them if they have a Steyr AUG as that's the same setup isn't it?

 

Edited February 8, 2022 by RostokMcSpoons
Gate replied

[Adolf Hamster]

so it's still firing bursts on semi?

 

the mosfet should only run while it's getting continuity between the 2 signal wires, it relies on the gun to shut off. if it keeps getting signal it thinks it's just being run in auto.

 

the paper will prevent the auto contacts from triggering, which is easy to accidentally trip when testing on the bench (the g&g v6 has the same issue, albeit with the "trigger" being mounted in a different place)

 

so the gun isn't shutting off, one thing to check- do you have ab enabled? if you do try turning it off as that can cause some weird issues (took me years to figure out thats what the issue with mine was).

 

the other thing, which is what you've been looking at, is that the contacts don't engage too early, in a position where the COL isn't able to trip them when it fires.

 

do you need it semi only for DMR power? if so then one way would be to remove the connection to the auto contacts

[RostokMcSpoons]

37 minutes ago, Adolf Hamster said:

so it's still firing bursts on semi?

 

the mosfet should only run while it's getting continuity between the 2 signal wires, it relies on the gun to shut off. if it keeps getting signal it thinks it's just being run in auto.

 

the paper will prevent the auto contacts from triggering, which is easy to accidentally trip when testing on the bench (the g&g v6 has the same issue, albeit with the "trigger" being mounted in a different place)

 

so the gun isn't shutting off, one thing to check- do you have ab enabled? if you do try turning it off as that can cause some weird issues (took me years to figure out thats what the issue with mine was).

 

the other thing, which is what you've been looking at, is that the contacts don't engage too early, in a position where the COL isn't able to trip them when it fires.

 

do you need it semi only for DMR power? if so then one way would be to remove the connection to the auto contacts

 

Yeah, still bursting on semi.

I haven't seen any method to switch off AB on the Merf.   I think I should have bought the Perun just because it has more tweakability

I haven't really worked out how the COL works, in terms of interaction with the other components, I'll need to need to find an explanatory video later.   But I had checked it moved ok and it didn't look like any bits had broken off it.

 

(Remember, I did have a problem where the piston broke at the back, when the piston head came  undone and ended up half way down the spring, so there's definitely potential for something having gotten buggered.  But of course that happened after I had the first instances of semi not working.
Original piston put back in and seems fine so far.
I've also got a gouged bushing under the bevel gear that I'll need to replace shortly.  I redid the shimming in the gearbox last night and discovered that problem, so I'll order some new 7mm bushings to sort it.)

 

This isn't a DMR build, it's just the site has some CQB tented areas where we can only go to Semi, so even bursts would make me unpopular

 

Edit:   Hmmm I just searched on F2000 COL, and apart from the fact it's considered a 'bad design' and an 'achilles heel', at least with the G&G version, I also found mention of the COL not engaging with the sector gear due to shimming.
I have had to shim the sector quite a bit as there was a lot of play initially... maybe I need to shim the COL as well?

Edited February 8, 2022 by RostokMcSpoons

[Adolf Hamster]

16 minutes ago, RostokMcSpoons said:

 

Yeah, still bursting on semi.

I haven't seen any method to switch off AB on the Merf.   I think I should have bought the Perun just because it has more tweakability

 

hmm, i thought you could turn it off on the merf, compared to say the nanoaab (picoaab? something like that) where it's permanent.

 

that could well be a potential candidate then, i certainly wouldn't be ruling it out as causing this as i've seen more than enough guns go from chugging all day long to barely scrape a few shots thanks to ab.

 

16 minutes ago, RostokMcSpoons said:

I haven't really worked out how the COL works, in terms of interaction with the other components, I'll need to need to find an explanatory video later.   But I had checked it moved ok and it didn't look like any bits had broken off it.

 

pinching this pic from earlier in the thread:

 

the trigger will push the trolley forwards, the col kicks it up, the return spring pulls it backwards over the top of the trigger (well, the trigger extension) until it's reset.

 

come to think of it, looking at that picture, is that spring (the one just above the arrow tip) getting pinched? kinda looks it? that should be the spring that pulls the trolley back.

 

16 minutes ago, RostokMcSpoons said:

(Remember, I did have a problem where the piston broke at the back, when the piston head came  undone and ended up half way down the spring, so there's definitely potential for something having gotten buggered.  But of course that happened after I had the first instances of semi not working.
Original piston put back in and seems fine so far.
I've also got a gouged bushing under the bevel gear that I'll need to replace shortly.  I redid the shimming in the gearbox last night and discovered that problem, so I'll order some new 7mm bushings to sort it.)

 

that shouldn't be affecting it as long as it's able to do a complete cycle. only real issues you'd see is either the wrong type or worn out col (unlikely in this case- i'm assuming those are original parts and not that old) or the sector gear shimmed way too high (again unlikely, it's pretty tricky to go that extreme)