ninja master of coffee Posted November 13, 2021 Report Share Posted November 13, 2021 I recently re-shimmed the gearbox of my CYMA AK as well as cleaned the trigger contacts which were pretty carbonised after a couple years of use. The shimming job went well in that the gearbox now runs more smoothly, however it has developed a new problem, which I'm not sure if it is linked to the shimming job or how to fix, as I've had the gearbox to bits a couple of times to no success. Basically, when swapping from semi auto to full auto, the trigger locks up. At first I assumed this was some issue with the selector levers but this doesn't seem to be the case. Rather it seems to be something to do with the disconnecter lever interfering with the trigger but I don't know why and and I don't know how to fix it. I don't know if anyone else has had this issue. I have a game tomorrow so I won't be able to work on it until after that at the earliest. Thanks for any help. Link to post Share on other sites
ninja master of coffee Posted November 19, 2021 Author Report Share Posted November 19, 2021 I had the gearbox apart again today to see if I could try to remedy the issue. No luck, there seems to be some lateral play with the disconnector lever but I'm not sure if this is normal and there doesn't seem to be any way to actually stop it. The issue also seems to have gotten worse after the latest disassembly but the weird thing is that it seems to be only something that occurs when the gearbox is actually in the receiver, basically, the gearbox will cycle when outside the receiver, both with and without the selector levers attached but once in the receiver the issue appears, now with the gearbox firing intermittently on full auto when in semi, and then firing one shot when in full auto, then the trigger locking up. This isn't the same as semi-auto lock up which I'm familiar with with version 3 gearboxes, this is the trigger becoming physically blocked. I could really do with some advice on this as I'm completely stumped. Link to post Share on other sites
Wingmann Posted November 19, 2021 Report Share Posted November 19, 2021 Without seeing it directly, I'd say it has something to do with how the trolley interacts with the rest of the trigger assembly. Be sure everything is ok after you cleaned those contacts. The disconector shouldn't have any trouble dislogding the trolley from the rail. Is the return spring of the trolley properly installed and not hitting anything? Link to post Share on other sites
ninja master of coffee Posted November 19, 2021 Author Report Share Posted November 19, 2021 When I looked the trolley seemed Ok, I was careful to reconnect the return spring correctly and it's an operation I'm used to doing. I'm wondering if I somehow reassembled the housing for the trigger switch assembly incorrectly so I'll have a look at that tomorrow. What confuses me is the fact that the gearbox works normally when it's outside the gun, but then develops these issues as soon as I put it back in the gun, this makes me think it's something to do with the selector levers but I can't really figure out what, aside from a little bit of ware, everything looks more or less normal and I'm not careless enough to miss-align the teeth on the selector levers. Thanks for your thoughts. Link to post Share on other sites
Wingmann Posted November 19, 2021 Report Share Posted November 19, 2021 Well, I think you can safely ignore the rear selector gears. Then you have the right side assembly, which only needs to be aligned, and then the left side with the selector plate and the spring that locks the disconnector. Check if the selector plate, the spring and the disconnector interact properly. I don't think any of the other parts are of importance here. Link to post Share on other sites
ninja master of coffee Posted November 19, 2021 Author Report Share Posted November 19, 2021 Thanks, yeah in fairness I haven't checked the selector plate carefully. It might be causing issues. Link to post Share on other sites
ninja master of coffee Posted November 20, 2021 Author Report Share Posted November 20, 2021 I had a look at the trigger unit today, everything looked normal but I took it to bits and gave everything a clean just to be safe anyway. The selector plate also looks to be functioning normally outside the gun. After fully disassembling and reassembling the gearbox the same issue appeared. I'm stumped. Link to post Share on other sites
ninja master of coffee Posted November 20, 2021 Author Report Share Posted November 20, 2021 Well, I solved it. It turns out the cables were interfering with the selector plate, pulling them back immediately solved the issue. I feel a tad stupid for not trying this earlier. Link to post Share on other sites
Wingmann Posted November 22, 2021 Report Share Posted November 22, 2021 Well, if you solved it you shouldn't feel stupid Some AK models have a space at the very back to route the cables, some have to be routed much farther to the front, but in all cases they have to let the selector move freely. Link to post Share on other sites
ninja master of coffee Posted November 23, 2021 Author Report Share Posted November 23, 2021 Yeah, I think I got focused on other parts of the gearbox and just didn't think of this, a friend suggested it might be the cables interfering with the selector plate, so I tried that and it worked, just wish I'd tried it earlier. It seems to be running fine now, though I did accidentally leave a shim out, which is a tad annoying. Link to post Share on other sites
ninja master of coffee Posted November 28, 2021 Author Report Share Posted November 28, 2021 Comment deleted Link to post Share on other sites
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