VKB MCG / GF Base Connector Issue - Causes intermittent failure of connection to base

[lazarusdmx]

1. Gunfighter Mk.II 'Modern Combat Edition' Gunfighter Model:Gunfighter Tabletop Grip: MCG PRO (direct from VKB webshop [Order #53434] (October 7, 2019))
2. Device Firmware v2.025 (also tested with older firmware 1.94.B and issue persisted)
3. I'm not 100% which springs are currently in--I think probably the factory 20s or the 30s, perhaps can be told from attached photos. I do not believe my issue is related to springs.
4. Cams are "30" type
5. I'm using VKB Device Config v0.91.78 (NJOY32 firmware V2.03.0)

About 3-4 weeks ago, I started to have disconnection while using the stick, typically at farther extremes of movement. The stick would work fine 90% of the time while flying helis in ARMA, but during extreme dips or side banks, the stick would loose connection and the stick LED on the blackbox (orange in my case) would blink red. At first, I thought I was having a grip connection issue or calibration issue. I reconnected the grips and recalibrated, no improvement. I flashed firmware again, no improvement, flashed an older firmware, no improvement. Eventually the connection issues grew, until the stick simply was flashing red LED on blackbox permanently. At this point I learned about the external devices tab in VKBConfig, and sure enough there was zero connection to the base or stick.

I had been reading the support forums off and on for a few days searching for information that could help me troubleshoot my issue, and I came across a response post in which someone described an identical issue to mine, including the progressive deterioration. In their case, it was due to a poor/failing solder joint on their Aviation 4-pin connector, and after re-soldering it, they were back in business. I ordered two replacement cables from VKB and in the meanwhile set about inspecting my original cable--indeed one of the black leads did look pretty sketchy on one connector. I re-soldered it such that it looked much better, however this did not resolve the problem. I thought, well maybe the cable is messed up otherwise, or my solder wasn't really that good. I received my replacement cables today, however, and they didn't resolve the issue either--still zero connection to the base.

At this point, I was fairly confident that the issue lay with a connector inside the gunfighter base/gimbal. Following previous official troubleshooting recommendations for similar problems, I had already inspected and cleaned the 3 spring loaded pins at the base of the MCG Pro, opened up the MCG pro to inspect the connections there, and disconnected and reconnected cleanly every electrical connection in the gunfighter base. At the time none of these steps resolved my issue.

Today, after discovering the problem did not exist within the aviation 4pin cables, I returned to investigate these interior connectors, and I think I have localized the issue. The internal 4pin beige cable plug at the interior of the base (on the other side from where the 4-pin aviation cable inserts). Visually, both the socket and the plug look fine--no missing contacts/pins. And if I reseat it, the LED on the gimbal board will light up red, and connection will resume for the Base in VKBConfig. Additionally I can attach the grip temporarily and it will also connect just fine. However, if I use the stick, or simulate using the stick (as I'm doing now since I got tired of reinstalling all of the hex screws each time) the connection fails. It will sometimes resume depending on which direction I move the gimbals, but it always looses connection.

Despite the plug being securely attached and there being no visible issue (at least to my eye, see attached screenshots) the connector intermittently looses connection during Gimbal motion.

If I hold a finger on the connector plug during movement, no disconnection occurs. I have done my best to make sure the cable is free of obstruction and does not apply pressure to the connection, but despite that, even the slightest movement of the cable results in a disconnection.

I'm unsure how to proceed solving this issue--I suppose I could try and rig something with a twist tie to apply constant pressure on the plug, but that doesn't sit too well with me. I'm looking for help on how to resolve this, and am happy to try and complete any additional troubleshooting steps. I miss using my stick in ARMA, MKB just isn't as fun for me!

Thanks in advance.

[fallout9]

Try to find out where exactly the issue comes from: plug, receptacle or wires. After that you could fill up a service ticket asking for the right part; you might need either the cable or the board. If you're not sure just mention it in the ticket and you might get them both. Pretty sure you won't have to pay for it even if you're out of warranty; worst case scenario those parts might not be available as they're not produced anymore, but in this case you could get the GFIII electronics upgrade kit.

[lazarusdmx]

I have a multimeter and can do continuity testing, any suggestions on how to go about narrowing down which component is busted between the plug/receptacle or board?

[Ron61]

Look closely at the soldering points of the connector to the board. It is possible to try to push them with the loop connected and monitor the quality of the connection in the configurator.

[lazarusdmx]

I did some further testing. I swapped out a similar cable from elsewhere on the gimbal, and the connection issue persisted; this lead me to believe it's a problem with the socket/board connection. I noticed that the socket has these small visible "L" shaped metal items at the back outside corners. One of the sides appears to be separated, or slightly away from the board. This would explain why the connection works if I apply pressure to the top of the socket--the connection is established, but when no pressure is present, connection is broken. It may not be easy to see--I took a picture of it:

What I'm wondering is if this might be something that could be solved with some solder? I'm not an artist with solder by any means, but it almost looks like something that a small amount would resolve--creating connection and stabilizing the socket. Otherwise a connector board replacement would solve the issue (or a MKIII upgrade kit, of course.)

[lazarusdmx]

a further update--went ahead and tried to repair the connection with solder... and it worked! when I plugged the boards back together, nice solid connection light. However as I continued reinstalling components, I noticed a sort of flaw in the design/potential reason for why the connection broke in the first place--one of the damper screws extends down and directly interacts with the 4-pin receptacle.

As soon as I tightened the top screws on the gimbal plate--I think it separated the solder joint I had just made and it's back to disconnection w/o pressure. Gotta go resolder it, and now I'm wondering if it makes sense to rotate the board so the receptacle is on the opposite side from the damper screw--it would be a slight bit of travel for the cable, but should mostly be free space under the gimbal anyway...

[lazarusdmx]

hmmm back at an impasse. I resoldered:

its not possible to install the board in reverse--one of the gimbal/cam heads is too close to install the plug. I backed out the damper screw as much as you can (it eventually hits the gunfighter top plate). Connection was good again, until I reinstalled the top plate--the damper screw still interacts with the plug receptacle, and breaks the now three-times soldered joint (and again, keep in mind that I'm not a pro at soldering).

I'm not really sure how to avoid/solve this issue--I can't get the damper screw any farther up. This obviously wasn't always a problem, though to be clear I have not adjusted the joystick since the first two weeks I owned it--installing cams and springs.

While working on the receptacle solder, I did notice that there is some slight play in the board>4-pin aviator connector bit--regardless of whether the outside nut is snug or not, the board has some rotational wiggle to it, meaning that it's possible that at start the board was clear of the damper screw, but over time started to wiggle a bit and strayed into contact with the screw, slowly causing the solder joint to pull apart.

[Ron61]

The damper screw does not come out more during rotation than in the photo. There is no thread, it is only on the square nut, which is spring loaded.
The backlash in the 4-pin output connector is standard - it is a plastic insert with pins in a metal case that moves. This does not affect the contact.

[lazarusdmx]

That's interesting. I can tell you this--there is elevation on one side of the socket--the backlash appears disconnected slightly, and when I solder it, the connection from base to VKBConfig is stable. Then when the case is further reassembled, the damper screw (which definitely did raise and lower based on my hex adjustment, but stays where it is once you've set it) interacts with it, in my case, which breaks that backlash/solder connection. I understand that this is not intended, and it obviously isn't something happening with most people's units--in my case I suspect the play in the threaded aviation connector (which is all that secures the circuit board) is the reason the damper screw and socket are interfacing. The mkIII board appears to be secured to the aluminum shroud via two hex bolts, so perhaps this was a design improvement for this generation.

Otherwise, this part is not affected by any gimbal movement during stick operation, as you say. That said, reversing the board results in no clearance at the socket because of static physical location of the gimbal/cam end on that side, so that is not an option. I agree, I didn't think the backlash had a specific function electronically--clearly the contacts in the sockets are directly soldered to the 4 contacts on the board, but I suspect that since the backlash on side is separated by interaction with the damper screw, one or two of the solder connections internally to the socket-to-board connection are damaged or severed, and come back into contact when the backlash is solder-repaired or physical pressure is placed on the socket manually.

In any case, I've submitted a support ticket, and will see what they suggest. Thanks for all your help.

[lazarusdmx]

just wanted to provide an update to this case, since I've now got it resolved thanks to VKB support. They shipped me a new connector PCB and associated wires, and after a couple tries reconnecting it (I did it wrong the first time, but support got me back on path) I now have full connection--all green again. Excited to get back to crashing my helo!

[fallout9]

Thank you for concluding the thread!