G940 MODDING (Warning large pictures)

[Sokol1]

JumpingHubert,

Is not case. Every with HALL sensor or high quality pots, ie. Bourns, Spectrol, the G940 reverse bug still. The problem is in firmware. MasterTec solve this with different controller.

G940 already use HALL sensor (Melexis 3D - same of T.16000M, Warthog) in X and Y axis.

Sokol1

[JumpingHubert]

ok sorry, i thought the g940 has cheap pots.

[Artist]

Originally Posted by JumpingHubert

ok sorry, i thought the g940 has cheap pots.

It does. Only the X and Y axes of the stick are hall-sensored. All other axes have 'cheap' pots (I've seen those on the throttle-levers when I modded mine): trim1-3, throttle-levers 1 an 2, R1 and R2, the pedals, and the 2 toe-brakes.

Purportedly this is the reason why Logitech has fixed (well, minimized) the ReversalBug on X and Y axes of the stick, but has not done anything about all the other axes, and as rumour has it, will not ever (see here and here).

The reason behind this refusal is - again a rumour - that the ReversalBug prevents users from noticing the wearing-out of the cheap pots - because they're already used to this kind of behaviour. It makes sense to me, because the ReversalBug is, as Sokol1 wrote, in the Firmware and (a) was easily fixed for the hall sensored axes and completely disappears when you connect the pot-sensored axes to one of Bodnar's boards.

Artist

[Allons!]

Originally Posted by Artist

It makes sense to me, because the ReversalBug is, as Sokol1 wrote, in the Firmware and (a) was easily fixed for the hall sensored axes and completely disappears when you connect the pot-sensored axes to one of Bodnar's boards. Artist

Hi Artist, nice to see you here in the wild. So a simple change of the potis wouldnt make a difference? Couldnt somebody just hack the firmware and change this all? couph Allons!

[Artist]

Originally Posted by Allons!

Hi Artist, nice to see you here in the wild.

Same to you Allons!

Originally Posted by Allons!

Couldnt somebody just hack the firmware and change this all?

Yes - and then take all the blame, the flaming, the accusations and the threats of those whose sticks gone dead while or after flashing the modded firmware onto it.* I am not tired of life, you know?

The path of MasterTec, me, and all the others is the best: Simple, reversable and no real chance of destroying something beyond repair.

Edit: And for those afraid of souldering irons there's - at least for LI-2 1946 - YaDeLi and MultiThrottle to reduce the ReversalBug on some axes...

Artist

*) Apart from being hunted by Logitech to find out who leaked the firmware...

[MasterTec]

Yes the problem is with the firmware. The problem was put into the firmware to help compensate for potentiometer wear. Had they implemented it correctly it would have been fine but they DID NOT do it correctly. This leaves only three options (other than simply throwing the stick away):

1> Wait for Logitech to come out with a fix which I'm convinced will never happen)
2> Re-write a new firmware for the stick (I'm not a programmer and don't have access to its source code)
3> REMOVE the firmware altogether.

I opted for #3. Yes I suppose that I could have just thrown the G940 away and started using my X52 again but this was a fun project, AND I get to keep my force feedback!

I've also done this mod to repair the throttle wiring:

OK I decided to tear back into my throttle to mount the BU0836 controller board into the throttle housing itself. That operation was a success but I suffered from strange glitches in the throttle when all was said and done. The trims would quit working if the throttle was set to less than about 95% and one of the buttons only worked when throttle was at full as well.

I tore it back apart and determined that the wiring going up the right side throttle is simply bad. I had some open circuits when the wiring was flexed a certain way so it was time to replace it.

I took some floppy drive ribbon cable and cut it into two six-wire strips:



Then I took the throttles apart and replaced the wiring with the ribbon cable:

BEFORE:


AFTER:


BACK TOGETHER:


The width of the ribbon cables fit perfectly into the recesses of the throttle arm itself and even with its metal support reinstalled I was able to slide the cable inside the unit to get the correct length at both ends.

Then it was just a matter of soldering the connections to the proper wires (there are 12 of them) on each end and putting the unit back together. I also had to make sure the cable was routed away to the side at the throttle base so it wouldn't rub against things while moving the throttle. I've used it several times now and it's working great!

Once I had it all soldered up I noticed that one of the thin wires at the four-pin connector that I had swapped the pins into had broken so I just eliminated that connector and soldered the wires directly. If it develops wiring issues now it's going to be at the 12 pin connector and if that happens I'm going to locate several old-school CD-ROM audio cables with the small connectors (uses the same pins but with thicker wires - see the image below) and swap those wires into the 12 pin connector at the throttle circuit board.

If Logitech had made those wires just a tiny bit thicker and made that harness just 1/4" longer then there would be no issues with it.. but they didn't.

[Artist]

Great, MasterTec!

I was lucky to know the cure before the outbreak and handled the problem before it arose (see here), but thanks for the howto (in case my fix doesn't help in the long run)

Apart from that I do agree with you:

1> Wait for Logitech to come out with a fix which I'm convinced will never happen)

No. It won't.

2> Re-write a new firmware for the stick (I'm not a programmer and don't have access to its source code)

I know about programming and even if I would get hold of the source code I would not touch it, much less distribute a modded version - for the reasons enumerated in my earlier post: I probably wouldn't survive it.

3> REMOVE the firmware altogether.

Right. And anybody who is not prepared to take this path should not consider to buy one.

Artist

[MasterTec]

I just wanted to post an update about my mod. It's now November 29th and it's still working great!

I have not had to reopen the stick ever since I rewired the throttle - I just plug it in and play several times a week!

[Sven]

I might have to do that new wire in the throttle as well, some of my buttons and trims only work at full throttle which is getting annoying

Does that really fix it? Because I have some of that wire you used here as well, floppy wire you call it?

Then it was just a matter of soldering the connections to the proper wires

How do I know which of the wires go into the connection unit?