Semi doesn't work based on how I hold the rifle? Interesting problem

[catsgowoof]

Hey ASC, my rifle's got a pretty interesting symptom which I've never seen before.

Here are the list of parts:
- VFC VR16 base
- BTC Spectre MK2
- Ace1Arms piston head
- Ace1Arms nozzle
- ZCI high torque motor

Issue started after I installed the BTC Spectre MK2. I highly suspect it has to do with shimming and the sector gear switch, but despite tweaks nothing has changed.

What's interesting is that when I lean the rifle towards the left (left side of the rifle facing the floor) or hold it upright, semi-auto will work for a few shots and then stop working (full auto still works). When I tilt it fully to the right (as in, right side of the rifle facing the floor), the rifle starts firing again! Very interesting symptom, any suggestions on what's happening? I'm trying to get a video up soon.

Notes:
- multiple batteries have been tried, all of them with good charge
- I am a n00b at shimming
- I've fiddled with the BTC programming; as of now motor braking is set to moderate and Pre-cocking is 20ms.

Any help is appreciated, thanks boys

[RainyEyes]

Alright so it begins. One noob's advice to another; I donno did you shim the sector gear weird so that the cutoff lever isn't resetting? The way you turn the gun makes it sound like something is off or you tightened the cutoff thingy too tight.

[catsgowoof]

Originally Posted by RainyEyes

Alright so it begins. One noob's advice to another; I donno did you shim the sector gear weird so that the cutoff lever isn't resetting? The way you turn the gun makes it sound like something is off or you tightened the cutoff thingy too tight.

I think you're right.. when I get some time tonight I'll try to re-shim it and get back to you

[Zeroroaster]

Also check your cutoff lever for wear and that the gear is actually catching it when you lean the gun over...also a shimming problem. When the gun leans over, if there's slop in the side to side play the gear may be dropping and failing to engage the cutoff lever.

[AnthonyG]

I just finished installing my Mk II on my VR16...


Its probably the selector plate for the spectre, assuming you removed the cutoff lever when you did the install... If it only happens when you hold it left the selector plate is probably falling away from the microswitches on the back of the FET, switching it into SAFE mode. Try adding tape or heatshrink around the metal part. I also modified mine slightly with a dremmel, by removing 1-1.5mm from the leading edge of the tappet plate to make sure it isn't stopped from being pushed all the way forward when the fire selector is actually in safe mode.

edit: For future reference: To mod my selector plate I added heat shrink around the green part. I also removed 1-2mm from the blue edge to allow the selector to move all the way forward. I found adding the heat shrink alone prevented the plate from moving all the way forward and engaging safe mode. I also removed ~1mm from the red edge to prevent the selector plate from hitting the stock VFC bearings which stick out of the gearbox slightly. That is all.

[catsgowoof]

Thanks for all the responses guys, I haven't had a chance yet but I'll try these suggestions out!

[catsgowoof]

SOLUTION FOUND:

+5 points to AnthonyG for diagnosing it based off text correctly! +1 points for everyone else being helpful

It turns out when I turned my rifle over to the side it wasn't working, the selector plate would actually come off of the fire selector on the BTC. It's working beautifully after I reconformed the selector plate with a pair of pliers to sit more flush to the gearbox.

Thanks everyone!

[lurkingknight]

did they fix the issue where if you don't shim the selector the plate actually doesn't make good contact with the selector microswitch on the trigger board? You need to add a layer or two of tape onto the selector plate in most cases. When you tip the gun over the plate is actually falling away from the micro switches. When no contact is made, the gun defaults to full auto I believe. Which is kind of a dumbass way to program. Semi auto would be a far more effective failsafe fire mode... or not at all.

Also check your cutoff lever for wear and that the gear is actually catching it when you lean the gun over...also a shimming problem. When the gun leans over, if there's slop in the side to side play the gear may be dropping and failing to engage the cutoff lever.

There is no cutoff lever in a spectre equipped gun.