Double Eagle M906C - Internal upgrades / tinkering

[RostokMcSpoons]

Cheers @Fatboy40 much appreciated.
 

I've had a reply back from Will at Spec Ops, he's said he's not had any problems with control units failing so basically he's unsure what could be wrong.  He'll take a look at it for me, but I as I can't spot an obvious problem then I think that'll be a waste of his time.   

 

A Gate Titan at £90 is a bit of a fiscal bummer at this point, I think I'll have to manfully struggle on with the other gnus in my collection until my situation improves, but at least it is, as you say, a drop-in replacement.  A tiny bit of soldering I could make a mess of, but otherwise reasonably straightforward.

 

@Skullchewer could you ask someone at Red Alert if they've had the same symptoms with any of theirs?  The symptoms are:
1) Super-hot motor  ... leading to

2) Double beep occasionally on spamming semi-auto

3) Full auto fires 3 or 4 before stopping (might be beeping too)

If they have any boneyard examples with a working control unit then I'd be happy to negotiate a price

... cheers! 

 

[ak2m4]

you seen this?

[mightyjebus]

next time you have it open snap a picture of the bottom board, in particular the square mosfet near the wiring solder points. I can't find a decent picture online but it looks like a 3503 mosfet maybe?

[RostokMcSpoons]

ooOOOOOOOOoooh!

 

just what I need, Evike, eh?

 

Edited August 25, 2023 by RostokMcSpoons

[Adolf Hamster]

Thought evike had a history of dissassembling guns to get otherwise hard to find parts?

 

Ie evike having the spare is not an indicator of the manufacturer providing them

[RostokMcSpoons]

Shame I'm going to have to wait 4+ months to get my hands on it regardless

 

[Speedbird_666]

Might be better off just sticking a Perun Hybrid in it and call it done. Much better unit than the Falcon anyway.

 

I will be selling off my M904G in the next week or two - I'm thinning out my collection and I have a bunch of other M4 platforms that I can use.

[RostokMcSpoons]

21 minutes ago, Speedbird_666 said:

Might be better off just sticking a Perun Hybrid in it and call it done. Much better unit than the Falcon anyway.

 

I will be selling off my M904G in the next week or two - I'm thinning out my collection and I have a bunch of other M4 platforms that I can use.

 

Yes the Perun is a bit cheaper than the Titan, and has the program-by-trigger functionality.  Seems good, but presumably I might need to finesse the gearbox to fit it?

 

If and when you do sell the 904, please give me a heads-up, I might well be interested in it as a donor / experimental backup

 

Edited August 25, 2023 by RostokMcSpoons

[JVacation]

@RostokMcSpoonsI've got two of the DE mosfets in my parts bag. Happy to sell them. They've been just sitting there but they were working when I took them out. 

[RostokMcSpoons]

20 minutes ago, JVacation said:

@RostokMcSpoonsI've got two of the DE mosfets in my parts bag. Happy to sell them. They've been just sitting there but they were working when I took them out. 

 

Haha I've just bought a 904g as a donor gun (spending more money than I'd liked in the process)... If only you could have made the offer a week ago 😭😂😋

 

Well, I'm still interested, the 904g can be a full spare gun rather than just a shell sitting in my loft, so please pm me with prices.  Please just bear in mind I'm a jobless hobo at the moment 🥴

[Herrgh]

Happy Easter all. Apologies for the necro, but there is no better thread for me to run in a panic to when I inevitably balls this up.

 

My beloved completely stock M906C gave up the ghost earlier this year, and after cracking it open I (rightly or wrongly) determined that the Falcon ETU was just broken, refusing to turn the motor (and only beeping after a lot of coaxing from me. Its been a while and I foolishly didn't write down what exactly it was doing). All other parts appeared to be in good working order, nothing stuck or caught.

 

So I'm sticking a Perun from @ak2m4into it, new bearings (cos why not), new XT 6.02mm stainless barrel (cos I like the colour and I had a new G&G hop up unit that I wanted to pair with it) and a new m105 spring. Motor I'll sort out later.

 

Please pray for me. 

 

 

[Herrgh]

I've already run into my first problem:

The Perun won't sit flat against the side of the gearbox case because of the "bump" circled below.

The Perun magnet holder that is affixed to the trigger is making contact with the horizontal post indicated with the arrow.

 

 

As far as I can tell the "bump" doesn't appear to do anything. I'll have to file these down to make everything fit. What tool do I need to obtain to do this?

[mightyjebus]

it's pot metal, either snap it off with a pair. of pliers or use a dremel

[Colin Allen]

Do not remove the post; the magnet holder should rest against it.

 

You will need to dremel off the raised screw hole that you have circled.

The manual is here: https://perunairsoft.pl/hybridv2.pdf

[Herrgh]

19 hours ago, Colin Allen said:

Do not remove the post; the magnet holder should rest against it.

 

You will need to dremel off the raised screw hole that you have circled.

The manual is here: https://perunairsoft.pl/hybridv2.pdf

 

Yes, apologies, I misread the instructions as saying that the magnet holder shouldn't be in contact with that post (it should!)

 

I don't have a dremel to hand but some hand files have done the trick.

 

Have done the sensor tests and it's all working! Now to reassemble it without too much cursing (ambi controls and working ambi bolt catches make for a poor first timer attempt at this sort of thing...) 

[Colin Allen]

1 hour ago, Herrgh said:

 

Yes, apologies, I misread the instructions as saying that the magnet holder shouldn't be in contact with that post (it should!)

 

I don't have a dremel to hand but some hand files have done the trick.

 

Have done the sensor tests and it's all working! Now to reassemble it without too much cursing (ambi controls and working ambi bolt catches make for a poor first timer attempt at this sort of thing...) 

Excellent! Well done!  I tend to disable the ambidextrous mag catches as they are a pain and I am not bothered by them.  I sometimes do the same with the ambidextrous selectors as well.

[Herrgh]

Held off on putting it back together as I needed more shims, which have now arrived. I've never shimmed before so I want to do a good job, but my god is this a boring process. It's like I've acquired a subject-specific instance of ADHD just for shimming.

 

That aside, I think I'm going to have to shim the sector gear higher than planned as I think it's making contact with the tiny screw holding in the Perun. Weirdly its only sounding like its contacting it with the same timing as the teeth meant piston rack (i.e. on off on off, not constantly in contact.) 

[Adolf Hamster]

6 minutes ago, Herrgh said:

Held off on putting it back together as I needed more shims, which have now arrived. I've never shimmed before so I want to do a good job, but my god is this a boring process. It's like I've acquired a subject-specific instance of ADHD just for shimming.

 

That aside, I think I'm going to have to shim the sector gear higher than planned as I think it's making contact with the tiny screw holding in the Perun. Weirdly its only sounding like its contacting it with the same timing as the teeth meant piston rack (i.e. on off on off, not constantly in contact.) 

 

tis a laborious process, a lot of assembling, testing and dissassembling to make changes.

 

it's why i'm not a fan of the m4 platform, lot of unnessecary steps to get to actual testing.

[Herrgh]

Sector bottom - 0.8mm

Sector top - 1.0mm

 

Spur bottom - 0.5mm

Spur top - 0.8mm

 

Bevel bottom - 0.5mm

Bevel top - 0.2mm

 

Ugh. I never want to be an airsoft tech thanks to shimming. Gonna try and put it back together.

 

(If the numbers above look horrifically off to you, please say so.) 

[Adolf Hamster]

"right" is something that is specific to each individual box, so we as outsiders have no way to say if that's too much or not enough.

 

If it sounds smooth then it's good.

[Herrgh]

It took me a while because of the ambidextrous bolt releases (I forgot how to put it back together and needed to go hunting on Youtube), but it's functioning again.

 

I will admit that a sense of impatience did overcome me toward the end, thus the shimming is probably "good enough" rather than "good". A few test shots show an FPS of around 285 on 0.25g with no hop. This did fall down to 275 on a second test - not sure why, but the fake bolt got a bit stuck around this point and wouldn't seat itself all the way home, so possibly that indicates something.

 

Almost certainly the air seal could be better - I thought chucking money at it all (see below) would result in something consistent, but I should probably take it apart again soon and see if there is any wear on any parts where there shouldn't be. I've done no AOE correction - it didn't look like it needed it (and I've been down a bit of a rabbit hole with regards to if it is really necessary...)

 

For my own reference, the parts swapped are:

 

Falcon ETU > Perun Hybrid V2

Stock spring of unknown strength > XT M105 Spring

Stock bushings and bearings > Zero J-Caged 8mm Bearings (potential clearance issue with the selector plate if I were to shim the gears perfectly? but no issues so far).
Stock 229mm brass barrel of unknown diameter > XT 229mm stainless steel 6.02mm barrel

Stock rotary hop unit > G&G rotary hop unit

Stock bucking > Maple Leaf Macron Green

Stock nub > Omega nub

Stock piston > XT 14 Tooth Piston CNC

Stock piston head > SHS Piston Head (6 Vents Aluminium)

Stock cylinder head > XT Cylinder Head Aluminium V2/V3 (Wide Pad)

More shims added (stock DE M906C has x4 0.5mm, x4 0.2mm, and x2 0.1mm unless I've miscounted)

 

I attempted to add an SHS Safety Latch (V2) but the selector switches really didn't like it, so I gave up on it (and it's not necessary thanks to the Perun).

Hopefully soon I'll get somewhere where I can test this out at range. As for upgrades, the next thing has to be a motor - the stock DE/Chaoli(?) motor is lethargic at best (and I could feel it getting every so slightly warmer than the ambient temperature after just a few shots). Dunno if I need to go brushless tbh - I'm more woodland focused than CQB, so I don't need the snappiest of snappy trigger responses.

 

Anyone have any thoughts on how to monitor how the new parts are all interacting with each other? I'm probably gonna have to take it all apart again relatively soon right?

 

 

 

 

(...oh crap I probably haven't put enough lubrication on the gears lol)

 

[Colin Allen]

You don't want to lubricate the gears too much when using the Perun; if you do, there is a risk of getting some on the cycle detectors.  If it is running well, there should not be any need to open it up again, unless/until it stops performing as you want it to.
 

You probably did not need to fit new bearings or change the piston parts and cylinder head, but that is done.  You did the job and it is running ok, which is good.