RostokMcSpoons

Oh damnit I've just put in the new trigger unit, cut-off lever, bushings, adjusted the shims appropriately, and used my new nozzle. My 'cunning plan' of super-short burst + lowered RoF still got me good single shot performance, in fact it's better than before as I didn't get any double-taps. Then I reset to default semi/auto and got the bad news. It now fires full auto all the time, rather than occasionally doing the semi-auto successfully. I'm not ruling out a mistake on my part, but I double-checked the fitting and wiring before test firing. I did notice the new trigger unit is differently sized to the original, so maybe I try the shuttle/dolly thing with the old trunnion and vice-versa to see if that changes anything. Or swap the COL back, as that seemed to move only a small amount when engaged by the sector gear... so perhaps that's the issue. Anyway, one good piece of news for me is that I managed to strip the gearbox, fit the new parts, and get it back together and firing in the space of an hour. Thinking back to the first time I took a gearbox apart and then spent ~7 hours trying to put it back together, I have come quite a long way!

Can you guess what is yet? Of course you can't - it's camouflaged and therefore invisible to the naked eye! British Army surplus MTP kit... UBACS shirt Windproof smock Trousers (All sized for someone who ate all the pies for lunch and had a couple of doughnuts for dessert) So that's my late autumn / winter / early spring camo sorted - the SpecOps site is mostly golden brown now so this should work a little better than my S95 DPM kit (which I think will still get used when the leaf cover returns). Desert pattern would probably have worked even better, but this is obviously a good all-year camo anyway. Also, arriving in the same postman's visit... V3 trigger unit, cut-off lever, nozzle and bushings for the next stage in my attempt to sort out the F2000's semi-auto problem. Wish me luck!

I've just ordered a nozzle from AK2M4 as it happens. It'll either go in my AK or my F2000, I'll probably try both. It's very very slightly longer than the stock TM one, so it might end up needing a new home

That's a very generous offer Iceni, but hopefully I'll be able to jam all the parts in and make it work. I've got three different hammers, how could it possibly fail? I rather wish it was the MOSFET, that'd just be a warranty replacement, or swapping for a Perun, or even just reverting to the old wiring, rather than this mystery box stuff! Oh, I've got a replacement COL on order too.

It's not shaped like an M4, so it's not airsoft The world doesn't need another M4, it needs some wacky shit with some personality to it, so well played!

My cunning plan of programming the 'fet has resulted in a gun which mostly fires semi, but throws in a double-tap every four or five shots. I expect I could get away with that, if I had to. But let's face it: the trigger action is bad enough with F2000's (and maybe bullpups in general) that you don't want to spend the whole game yanking away on the damned thing! Plus I upgraded this gun to enjoy some high RoF antics (not full wanker-mode, obvs) I must say I'm disappointed that a Cyma-built gun has turned out to be quite this fragile. Or perhaps my upgrade attempts have been a bit too ham-fisted. Edit: Is there any chance the cam on the bottom of the sector gear could be the problem? Should I buy a new gear too?

Just took the gearbox apart again, moved one of the thicker shims on the sector gear from the bottom to the top, in the hope it would engage better with the COL. And tried your thing of removing the trigger contacts. As per usual, it worked fine on the first couple of shots, where I was squeezing the trigger gently, but as soon as I got slightly medieval on its ass and tried a more realistic trigger pull, "rat-a-tat-a-tat" I'm going to re-set the wiring to use the MOSFET again, to try my cunning plan, and then it's down to those alternative parts. Confidence is not very high

I forgot to breathe and it nearly killed me 🤮

I've looked again at the manual for the Merf. I think if in the worst case I can't fix this, I change it to SEMI/BURST... and then tweak the burst timer down to its minimum, and set the RoF reduction to its maximum and so if/when it goes wrong it fires only a one - or at worst two - shots and I can then get away with using it at my site It'll be an interesting experiment for tonight anyway!

I saw that! But... Compatible only with G&G F2000’s without an ETU (pre-2019) I'm not sure if that means 'only G&G' or really 'Only V3s without an ETU'. Given the G&G doesn't use a standard v3 gearbox, I'd have to ask them first. Cheers It'll be great to have my pew-pew pew, or pew-pew-pew on demand

The COL shouldn't be worn, the gun was new at Xmas, it's had a less than a couple of thousand BBs through it. I have taken it all apart a few times though, and as I'm still "low on the foothills of Experience Mountain", I may have buggered it up somewhere along the line. The fact it does work quite often before deciding it'd rather crap over everything is odd. A bit of heat in the system makes it go wrong? Maybe a tiny bit of expansion makes a 0.01mm difference somewhere and that's enough to b0rk it. However, I've now seen enough other people complaining about similar issues with their F2K's (though mostly G&G which is very differently built) that maybe it's something that can just easily occur. Hopefully the Rocket after-market parts will get it back on track, but I will try your suggestion tonight in the meantime.

I bodged it back to pre-MOSFET wiring, and it still does it. So the there's definitely something wrong with the trigger / COL assembly. I've got some slo-mo video too... very instructional! I can see the contact dolly moving up and breaking contact on the semi shots, and shuttling back and forward whilst flat on the burst/full shots. I'll edit them down and upload them to YT shortly. The interesting thing to note is for my first video I used a thicker piece of card to block the full-auto contacts, and that seemed to help it stay semi-auto. When I recorded the second I just used electrical tape ... and eventually it does the burst/full. In any setup I find that once it's started to do it, it keeps on doing it. Maybe something is sticking? I'm using silicon gear lube from AK2M4 sparingly on the moving parts - but perhaps it's too viscous? Should I get some silicon spray in there to thin it down? Edit: Decided the one video was enough: the first couple of shots go on semi correctly, it's all downhill from there... Epic slo-mo sounds Edit2: Ah sod it, I bought a replacement Rocket trigger unit and COL from @ak2m4 ... let's see if those will help at all.

The spring does look a bit awry in that previous pic, but it looks ok to me now... The sector gear has 2 or 3 shims underneath and 1 or 2 on the top it so yeah it doesn't seem that likely to have got it out of position. Another reddit thread suggested going back to 7.4v, so I've just tried that. Same thing. So pretty sure there's a mechanical issue hidden in this thing somewhere! When lunchtime arrives, and I can spend some quality time on this, I'll change over the contacts (which I don't expect to fix it) and then record some video. It'll give me a reason to try 'Slow Motion' mode on my phone camera for the first time ever And if I get really, really, really stuck with this I'll try to put it all back to pre-MOSFET mode to see what happens then.

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?

(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?

I've taken the same journey, so you might want to catch up on my thread... I haven't changed the motor or barrel or hop unit... I'll be interested to see how you get on if you do change those, so please make before and after accuracy tests to prove what changes are really the most effective.. That would be very helpful to the community I'm currently very happy with my gun after the change of spring, bucking and nub, but would always welcome more accuracy. The motor is fine (IMHO) , especially when driven by an 11.1v battery Your shopping list looks the same as I'd make. So good luck 😊

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!

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

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

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

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 ...?

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?

Yeah, seconded as my TM AK47 isn't feeding well on full auto after its 'upgrades'. If it's your only gun then my advice is to use it until it breaks (which might be a while), and concentrate on getting closer to the enemy (decent camo / fieldcraft) If you've got a reliable back-up, or don't mind paying for a rental on the day if it doesn't work, good luck (Good excuse to re-use an old pic)

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!