Possible MMM design flaw?
 

This guy post has me worried about my wiring on my Flux ESC. Any recommendations Castle to prevent this?

http://www.savage-central.com/module...wtopic&t=83350

Old news - Secure your esc properly...

The leads were strained - the excess wire on RX wire was I'm sure just compression of wire coating which could have been "stroked" back down...

Fan cable routing has been discussed many times but in this case he broke the entire connection off...

Good luck with the HW150A mine smoked after 10 runs... waiting now 2+ months for V2...

WTF? That dude clearly abuses the hell out of his truck if he landed hard enough to do all that. I'll be he bent his motor mount too and the motor is gonna burn out soon from absurdly tight gear mesh.....

However, instead of regular double-side tape, if you use the type with about 1/4" of foam in between the sticky sides that will absorb impacts much better and greatly reduce the chance of damaging the ESC as catastrophically as that guy did. :sigh:

it's a savage forum!! what do we expect?

I found my fan connector fall off too. I've replace MMM fans several times, this time I thought it was just as usual--replace the fan and go. But when I open the case I found the connector was off and the fan is okay. Soldered the red and black wires directly to the PCB pad, now I am guessing what's next to damage, PCB traces?

I'm the guy who posted this on the other forum.

I clearly abuse my truck, I admit. I'm not the kind of driver doing nice circle on a track, more a hard basher and I love big jumps.
Although I agree my driving style puts a lot of strain on the truck, the Flux and MMM still have some design flaws:

1) The MMM installation in the Flux is too weak.
Double sided tape + 1 nylon strap does not hold for long enough (especially when the rear shock tower bends too much). I tried several types of double sided tape with no luck.
Actually my mod with a second nylon strap perpendicular to the stock one works very well. The reason it failed on that particular crash is that I cut the excess strap too close to the "buckle". I now have the same setup but cut an inch away from the buckle and it works great. No more ESC moving.
I'm still having a plan to buy the Traxxas E-Revo BL mounting hardware for MMM and use it along with a new plate to the Flux stock one. To be investigated.

2) The routing of the wires from the MMM PCB to the fan is stupid
The wire just scrubs against the edge of the PCB and insulation goes away.
Since I've replaced with thicker wires, I hope this will reduce the issue.

3) Direct soldering of RX and switch wires is also stupid
These wires can be exposed to serious strain, and in case of failure, you have to resolder them (something not anybody can do) or worse if the soldering pad is gone.
I'd rather have some good outside connectors, like ezRun does.

don't hit skate ramps or whatever and flatland it. it does this kind of damage, and it looks stupid anyway, try and line up with a downramp and you wont stress your cars so bad and have these problems.

Don't get me wrong, there are a lot of really knowledgable people here, but a lot of castle creations defense too, no matter what the problem.

Personally I think the mount could be better in the Savage Flux, which is why I have my ESC mounted in a Jiffy Box. It's some protection.

I don't like the fan set up, I would prefer to run a BEC powered fan that is on at all times, but that's personal preference.

Perhaps look at how I have chosen to protect my MMM in the same truck.

http://i212.photobucket.com/albums/c...s/IMG_2465.jpg


I also want to shorten the motor wires but not sure if you can on these.

It's not bulletproof, but I think it's safer than what was there, certainly has a barrier around where the motor plugs go into the esc which can get hammered by a flexing shock tower.

As you say, the mount in the flux leaves alot to be desired, but that is HPI's fault, not CC. Unless you want to toss the flux you will have to improve on the mount...

The fan and signal wiring is not that great. I detailed how to re-route both and mod the case to allow some shrink tubing to be placed over the signal and switch wires to help with the rubbing and add so strain relief. You should also secure all signal wires to the chassis solidly and leave some slack to allow for component/chassis flex. Anyone who has built a kit should know this by now...

Like anything else made these days you can improve/modify the design. That is part of the fun in this hobby, personalizing the truck to fit your needs and wants.

The MMM installation in the flux is HPI though, not CC. If HPI had gone with a mount like on the revo, it would be much better off.

I beat my trucks when bashing, and still never have had anything like this happen. I have had the tiewraps break off and the ESC come flying out, and this has never happened. I really cannot see how any of this is CC's fault.

I am also still on a V2 with the latest firmware (upgraded from and original V1 that died) and do not have problems.

that is what happened just now with ben's MMM. he had a "super clean" setup where no wires can be seen, and when his MMM detached from the esc mount in his eight, they got yanked right out. have at least some slack between the RX cord and where it's tied down so that it can hit the body and dissipate most of its momentum.

If you read me carefully, I talked about Flux and MMM design flaws. Obviously #1 was for HPI, #2 and #3 were for CC.

If your ESC is flying, you break the on/off switch wire because you have this stupid wire coming of the front of the ESC, going under the mounting plate to reach the switch with almost no give. That's what happened to me.

The way the fan wire is routed inside the box is stupid. That is poor design on CC's side.
Then having the Rx and switch wire soldered directly on the PCB and coming out of the box with no strain relief device whatsoever is also very poor design.
If I did that for my customers, I would already be looking for another job!

then again, with detachable wires, you open up a whole new set of issues. they wont be secured to the speed controller, meaning that bumps and such can knock them out. that would also mean that they would have to start to manufacture and sell replacement switches and RX leads for the ones that fly out of the car into space, never to be seen again. that would definitely suck on a race day. there are always pros and cons to every design, and I'm sure it was looked at before put into production.


Now, this may be a little far fetched, but since we're on the subject, why not have a MMM DSM and a MMM FHSS model that have receivers built in to the speed controller! just plug your servo into your MMM, power it up when binding, and viola!

Just get a TRX mount for the MMM. I have mine secured with dual foam pads and screwed down with the mount(on an erevo though)

My suggestion to you then is to design your own perfect ESC and sell to the masses. :yipi:

Or you could contact Patrick and apply for a job at CC to fix all their problems. He is quite accessible.

Of course your real issue could be the tact at which you approached the situation in general. :whistle:

In reality though, had you contacted CC initialy about your problem, they probably would have helped you. :yes:

But how exactly?...

I use the Erevo esc mount on my gmaxx, and the esc doesnt move a millimeter- a foam pad underneath adds some cushioning, whilst the rock solid mount prevents the wires from gettgin yanked or tugged at.

What you can do is add a little clearance to the esc case where the rx and switch wires exit, that should releave the pinching issue; adding thicker wires will only make it visably worse (tight spot to start with afterall).

I will agree that there have been plenty of people with worn through insulation in the past, and it is caused by the poor wire routing and sharp edges of the pcb; I just think that there arent too many other ways to route the wire inside the cramped case, but as Linc pointed out, you can make a few tweaks to alleviate the problem. I myself just enlarged the opening for the wires to exit the MMM, and they've been fine for 2 years or so (MMM v1).

I'm not a racer, I'm a basher, which is why it's a good solution for me. If the connector is knocked out, the truck stops, I just have to put it back in and ready to go again.
With the damage I suffered, the bashing session was ended and it took me over an hour to go things back into working conditions.

To each his own optimal solution I believe.