Dunno about that either. To me, the BEC would bring the battery voltage down to ~6v, and then there would be an onboard regulator for the 3.2v supply. It's the only thing that makes sense considering how these things act when they fail.

I think the BEC must do the majority of the step down - One thought though is that the Brian board may still be able to operate at 2v whereas the servo and rx can't....

Just as a precaution - I'm going to give up on running with the BEC powering the Servo/RX and use an UBEC. I'll leave the fan off the MMM as it shouldn't run anyway...

What that tech is saying doesn't make real sense....unless the brains has its own power source or something to regulate and step down the higher voltage input from our batteries. highly doubt it

Plus, why else would the brains work via the castle link, but not off the battery? The Castle link provides the needed 5v to power the brains.

Well, I did the Bec removal mod and my dead V2 is alive again...

Hope it lasts! I will bash it extra hard. I am trying to run the truck hard to break any weak points, including the electronics. I will say that the hacker 11xl on 6s will easily launch the lst 2 feet in the air and flip it 2 or 3 times from a standing start... Way too much power, just like I like it. Plus the motor stays around 150f. I may step to a 1521, but I am not sure if it will make much difference.

AFAIK, you are the fourth one to do this mod. One user (brushlessboy) attempted and did something a little wrong. Another (TruckBasher) did it and it worked for a time, but eventually went south again (no idea why). Hopefully yours lasts a while, and if not, hopefully CC will honor the warranty.

Good to hear that.

Anyway, are you using a UBEC or Rx pack?

I talked to a rep from CC last night (I have to call at least almost midnight due to time difference) and asked about doing the BrianG mod.

So anyway, I'll be doing Brian's mod but instead of a UBEC(just ordered Dimension Engineering's Sport BEC), I'll be using one of my 6V rx packs from nitro revo. If it doesn't work, I will be shipping a dead MMM to CC and wait a couple of weeks for the replacement ESC to arrive unless Lutach's 10S Chineses ESC arrives first.

You actually said "the BrianG" mod? They're gonna hate me when I decide to stop by someday...

Yes I did :lol::lol:. Hopefully they'll give you something as a token of gratitude :party::party:.

I decided to use a rec pack, as i really do not feel like soldering up anything right now! I may invest in a novak regulator and use a 2s lipo pack, but atm I will be using a IB nimh pack...

Technically, I was the fourth, but it didn't work for me. Bleh.

Did you disconnect the red wire from the ESC?

Lito, no need to remove it...its for back feeding the MMM

Brian, just curious if USB can back feed brains while the switch is off/batts disconnected do you think we can back feed the MMM brain without your mod but leave the switch off?

BTW i got my 2nd MMM but not sure if I want to mod it cause the first one is already out of warranty and I dont want another junk.....I sure hope we can find solution to this mess

Not sure what backfeeding the ESC while keeping the BEC intact will do. Depending on exactly what is bad (and how), it could basically short the external BECs voltage (which would send the external BEC into a cycling shutdown condition).

Back during my first mod, I was using an external BEC and didn't remove the red wire at first. Well, the KF voltage was ~6v, but the MMM BEC was ~5.5v and the KF heated up quite a bit. That tells me right there that the MMMBEC was heavily loading the external BEC because of the higher external voltage. So, even when everything is working normally, using an external BEC AND the internal one at the same time doesn't work.

This is what I think killed BrushlessBoy16's MMM as he did this for a while and even Brian's chip removal mod failed to revive the controller.

I did the mod and it didn't work. It let off a small puff of smoke after I plug the rx pack (the red wire was not removed) and lipos. The rx pack is 5-cell hump pack from one of my nitro trucks. It was also hot. I'm not sure if the lipo or rx pack caused the smoke :oops::oops::oops:.

So anyway, it's officially dead. That's my first V2 to die.

Back to the waiting game again :no::no::no::no:

You must have accidentally bridged a solder pad or two - easy to do when they are so small. Do you know what blew?

I don't know the part name but here's a pic. Both are circled in red.

http://i256.photobucket.com/albums/h...hassis/MMM.jpg

Those look like SMD capacitors

Regards,
Joe Ling

Yeah, and I wonder if you had the BEC leads reversed (switched the + and -)? That's the only thing I can think of that would blow a cap, that and overvoltage.

I used an rx pack. It's a 6V hump pack. I had the wires from the ESC intact and plug in into channel 2 while the hump pack was plug into the battery port of my futaba rx.

Well, if the polarity was ok, I guess it could have been overvoltage. A 5-cell rx pack can be close to 7v right off the charger (~1.4v/cell). Usually, the caps have some sort of safety margin so I wouldn't think that would be it.

Unless the removal of the components wasn't quite done right and a couple pads were bridged putting the full battery voltage on the BEC line. That would definitely cause the rx pack to get hot, and the voltage would be high enough to pop those caps.

BTW: the larger device does look like a cap, but the upper one looks like it might have been either resistor, cap, diode, or any two-terminal device.

hmmmm I was using 5 cell pack also close to 7v after charging but it did not puff smoke and was alble to run for 15mins before it died....


Sorry to hear bout that Lito ......

I'm leaning more towards this. It's really hard to see if there was any bridging. Heck it only takes a speck of solder bridge to components together and cause some damage.

The hump pack has about 6.5V when I check it with my Fluke.

Jeff, have you opened it up yet and see what happened inside?

Hehe this is why i suggested to use the utility knife or your surgical knife :lol:

Whatever the case, I hope CC still accepts the warranty for you.

hey Lito maybe we can send it together.... but i think they will not cover warranty...Anyone know how much will be the payment for no warranty?

They better be:angel:. I spoke with one of their reps before doing this mod just to make sure. He said, "go ahead since it's dead anyway. Just send it back if it does not work".

So I guess it's better to ask permission first :lol::party:.

It's all boxed up now ready for shipping :lol::lol::lol:.

Jeff, I'll take home some surgical knives from the hospital next time I do a MMM surgery.

Ya, I would like to know too as I have 2 units that are void of warranty...

I heard from somewhere it's USD50 no questions asked but maybe this is only relevant to the MM. Can anyone confirm ?

Regards,
Joe Ling

Yes thats the MM price, there is a big list on their support page, but the MMM isnt on there yet.

Did you do anything to them?

Yep I did the BrianG mod :whistle:

Regards,
Joe Ling

It's $75 or at least that's what I was quoted.

I tried the mod on my new dead MMM and unfortunately it didn't work for me.

I believe I did a good job, no shorts etc but something started to smoke each time I
connected a Rx pack to it. I hacked at it a little too much trying to make sure
nothing was contacting but it still looks like it should work.

I have identified the component that is smoking, its not dead yet but will be soon
if I keep trying. (marked in yellow)

Earlier, as soon as the ESC stopped workng I tried to connect to Castlelink but the
USB interface thing got hot real quick. Checking the BEC lead it showed a short between
the +/- wires so maybe theres another problem and its not repairable.

http://i109.photobucket.com/albums/n...mm_bec_mod.jpg

Does anyone know where the factory internal bec feeds it's power into the board, so that we can "forward feed" the current from an external?

Definitive Post On Mmm Mods And Warranty
 

PLEASE BE ADVISED, ANY MODIFICATIONS TO CIRCUIT BOARDS ON ANY CASTLE CREATIONS PRODUCT, WHETHER OR NOT THE ESC WORKS, VOIDS THE WARRANTY. IF A CASTLE CREATIONS ESC STOPS WORKING AND IT IS LESS THAN A YEAR OLD AND IT WANS'T ABUSED IT IS UNDER WARRANTY. IF THE ESC QUITS WORKING AND YOU MODIFY IT IT THE WARRANTY IS VOIDED. THE MOD SHOWN ON THIS THREAD PROBABLY WILL NOT WORK FOR MOST PEOPLE BECAUSE IT TAKES SPECIALIZED EQUIPMENT AND SKILL TO REMOVE COMPONENTS FROM OUR CIRCUIT BOARDS. WE USE LEAD FREE LIQUID FLUX HIGH TEMPRATUR SOLDER THAT DOES NOT WORK LIKE LEAD TIN FLUX CORE SOLDER. THIS MOD ONLY WORKS UNDER CERTAIN CIRCUMSTANCES AND IN MOST CASES ONLY DAMAGES THE BOARD OR LIFTS COMPONENTS ON THE OPPOSITE SIDE OF THE BOARD.

We are seeing problems with certain set ups with the MMM v2. Most (over 2400) work great with no problems. We cannot recreate these problems no matter what we do here to the ESC and its BEC. The failure points are not consistent and we are trying to track down what the problem is. Whatever this is, it will be fixed. If you want to help, and have not already done so, fill out Thomas’s request for information sticky on the forum.

A failed MMM will be repaired/replaced at no charge within one year from date of purchase. If there is any work on the circuit board or other obvious modifications, or there is crash damage, the ESC is out of warranty and will cost $70.00 for out of warranty replacement.

What about modifying the case as it rubs on the fan plug ?





"If there is any work on the circuit board or other obvious modifications"

Thanks Bernie. Very clear.

Glad to hear you guys are on this.

The only thing I am having a problem understanding is the low percentage failure rates CC is currently reporting. I personally know of 4 MMM V2s in my local area. All 4 have failed. I know this is a very low sample size, but if all 4 of us got one of the 1.5% failure rate I am going to go and buy a lottery ticket right now. The odds on that are astronomical. (Edit: did the math... odds are over 19 million to 1 of this happeneing at 1.5% failure rate. I'm not that lucky, or unlucky)All 4 are running different setups in differnt types of vehicles. The setups on the setup data collection thread are all very different accross the board. The only common thing I see in all of the reports is that the failures were using the on board BEC to power the Rx and servos.

I just got a 2nd MMM V2 and am planning to run this one with an external BEC. So far in that data collection thread not a single faiure has been reported while using external BEC or Rx pack.

Do you know of any failures reported from people runnig the MMM V2 with an External BEC ort Rx pack and the red wire pulled on the rx wire? Id be wiling to run this way if it will insure reliability.

Also,

Point your guys to this post.

http://www.rc-monster.com/forum/show...000#post211000

I certainly think the constant pounding the brain board takes due to the fan plug and case design could be contributing to the inconsistant component failure points on the board.