My DBoys used to be shooting in two to three burst in SEMI but all of a sudden today when I went to test fire it, it started shooting in full auto in SEMI. I not sure if it has to do with a spring or a piece. It will stop firing when I release the trigger. I will be getting internal parts over the weekend like a anti-reversal latch, wiring (Rear), air nozzel and other parts(Piston, spring, spring guide, etc...). Any help will do. Thanks.

dryndantheman Registered User

It's more then likely the contacts and or the selector plate. Replacing the anti-reversal though would be a re-assurance.

Leftyflip Registered User

It sounds like the cut-off lever or the sliding contact to me. One or both are worn out. The A/R latch will make no difference.


Leftyflip said:
It sounds like the cut-off lever or the sliding contact to me. One or both are worn out. The A/R latch will make no difference.

If it's the cut-off lever I'm alright as I have a spare one in an old V.2 Gearbox.




The SEMI is still firing in bursts so I decided to open up the DBoys gearbox tonight. One thing that amazed me was that the gearbox already has a anti-reversal latch. While I was checking the trigger contacts and the selector plate, I decided to change some parts in the gearbox. They were from my old A.P.S. airsoft rifle and there only temporary:
- Spring.
- Piston.
- Cylinder.
- Cylinder head.
- Air nozzle.
- Gears (All three).
- Selector plate.
- Upper part of the trigger contacts.
- Cut-off lever
(I've also change some small springs).

Even after changing the cut-off lever and the sliding contacts it's still firing full auto on SEMI. Would it be the lower part of the trigger contacts. I also took a few photos but they're not much:

glicster Registered User

seen as youve changed the gears,cut off lever and sliding contact and now its constantly fireing full auto there could be the possability that you shimmed the spur gear too high and thus the gear is missing the cut off lever from being too high.

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THE MINDER Registered User

On top of what glister has said I can tell you the not all V2 cut off levers are compatable with the Dboys mechbox-they dont interact with the trigger block correctly-try fitting the switch of your APS along with its own cut off lever

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Does the selector plate travel relatively smoothly or is it clicking(getting a bit too caught up) while you slide it from left to right on the shell (from safe to full)? Is the small bit attached to the spring seemed to be obstructed or moving too freely?

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@ glicster
Even before I change the parts that you named it was already firing constantly on SEMI.

Thanks for telling me that. Unfortunately, the wiring for my A.P.S. airsoft rifle is stripped and I don't have a spare fuse.When I think about it, I was on the AirsoftGuns.ie website a while ago and I noticed that they have a ULTIMATE V.2 wiring (Rear) and a ULTIMATE cut-off lever for not a bad price. If I was to buy these and replace them would it do?

When checking the selector plate, from SAFE to SEMI it runs smoothly but then when I switch it to AUTO it makes a quiet click. I can't hear it until I put my ear up towards the selector switch. When switching from AUTO to SAFE it still runs smoothly. I've replaced it with the A.P.S. selector plate spring which is better than the standard one in my opinion.

As I already mentioned, if I was to buy the ULTIMATE V.2 wiring (Rear) and a ULTIMATE cut-off lever from AirsoftGuns.ie, would this by any chance fix the problem?

THE MINDER Registered User

The ultimate gear(Should work) is not that cheap so you need to decide how much you want to spend upgrading a dboys box before you go any further-consider an upgrade of aeg Incidentally the APS nozzle you put in will ONLY work properly with its own hop up chamber and bucking(check the shape to the one you removed)

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There should be a quiet click as I believe that's the disengaging of the part that cuts off after every shot when the AEG is in Semi. If it was louder then it might be catching or not properly engaging. Unfortunately, I don't have a gearbox handy to check myself or oen that's easily accessible

Glicster did mention that the cutoff mightn't be engaging properly and that can happen anyway whether you installed parts or not. There should be a screw on it, maybe that's too loose/tight?

The APS nozzle can be a problem as THE MINDER said.
IF the APS nozzle is too small for the hopup chamber, just use a bit of insulation tape on it to fatten it up and improve airseal, don't apply any within 1 or 2mm of the end or too far back (you can cut bits off carefully). Afterwards, put on some silicon grease. You want the nozzle fitting snugger for a better airseal but not too snug so that it's cathing/stuck or the airseal is too good and you're over the limit.

I know this because when my APS was down to about .5J I just improved the airseal and the nozzle alone got an extra .2/.3J. Infact at one point I went upto about 1.05J so I had to slip it back down a bit. I was using a G&P hopup unit at the time.

I got my grease from here and I don't think that I'll ever have to get more.

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Thanks for the tip about the air nozzle. I should be getting a new hop-up and a air nozzle soon so I'll be using the A.P.S. one for now. I'm still trying everything and I'm now convinced there's something wrong with the trigger contacts and the cut-off lever. I'm going to put everything into my A.P.S. gearbox shell and check.


Still ain't working...

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