Need response from a Castle tech for MMM question

[joeling]

Nah, just gimme a year's supply of free CC products will be fine & I want it shipped courier.

Originally Posted by suicideneil

Excellent news- CC should give you guys a job...

BTW, it's day light once again. I will try out this guy in the afternoon if the rain does not come.

Regards,
Joe Ling

Waiting....

maybe someone should do a step by step how to on the MMM bec removal mod you guys are doing....maybe in the long run you guys can save a lot of our MMMs from dying ...lol....thanks

[slimthelineman]

im not steady handed enough to unsolder the tiny @$$ parts on the pcb could i run an external bec and maybee see some extended life from my next v2?

[joeling]

I'm pretty handy with a soldering iron but I can't unsolder SMD parts as well. What I did was to use a brutal wire cutter & chomp away at the chips until I severe the connections & destroy the parts. I did use a desolering gun to attempt to suck away the excess solder for show show only. Couldn't be sure how much it helped. I did however use a multimeter to check that there is no short between pads but also take note that some pads are common.

Originally Posted by slimthelineman

im not steady handed enough to unsolder the tiny @$$ parts on the pcb could i run an external bec and maybee see some extended life from my next v2?

In my experience, running an external BEC without the mod will not work. U need to remove the parts. I was already running an external BEC in my V1 buggy conversion when it died & I had to follow BrianG's way.


Regards,
Joe Ling

[slimthelineman]

WOW that sounds like alot of fun!!!! can i use my kleins?lol thanks for the quick reply. not sure if i want to do this yet still trying to get a hold of castle about #1

[ptt81]

Here is something to try if you dont want to void your warranty, I know external bec and fan might not solve the problem but it could take the load of internal bec and rule out problem with fan, fan wire/plug

http://monster.traxxas.com/showthread.php?t=435810

[slimthelineman]

do you think castle would do this mod for a fee? i would like to avoid the internal bec completely if thats all it takes. even if i use an ubec without the mod then the bec will still be running all the time just with no load, so its only a matter of time until...

Originally Posted by slimthelineman

do you think castle would do this mod for a fee? i would like to avoid the internal bec completely if thats all it takes. even if i use an ubec without the mod then the bec will still be running all the time just with no load, so its only a matter of time until...

LOL....i was just thinking the same exact thing ....or wondering what kind of shop i could take this to to have it done ,as long as i know what exactly needs done ...cause i know there's no way i could do it ....LOL....maybe there's someone on here that would like to make a little extra cash .......although i can't believe i just paid 200 bucks for this and now i'm gonna have someone tear it up

[slimthelineman]

yeah a little bummed myself but what can ya do? CC will work it out, now if i could just talk to someone there.....

[BrianG]

The only thing using an external BEC does is isolate any external loads. But no one knows exactly what is causing the BEC to fail. Is is overcurrent? Is it some voltage spike thing? Maybe just an IC reliability issue totally unrelated to current or voltage.

The mod is fairly easy to do, but there is room for problems. It can be done with an less-than-ideal iron, you just have to make sure you don't create any solder bridges or unsolder adjacent components with the heat.

The surface mount ICs have some sort of adhesive aside from the solder connections. So, breaking apart the ICs may be easier, but also increases the chance of wrecking a nearby trace if not careful.

In my case, I removed the components in the following order mostly due to ease:

1: Desolder the fan connector.

2: Cut the small leads connecting the coil itseld to the connections leading to the PCB. Then, remove the leftover leads.

3: Desolder the two FETs. If your iron is not small enough to do this reliably, you can break apart the two FETs, and then desolder the little leftover legs still attached to the PCB. Clean as much extra solder off as possible to avoid bridging to nearby traces.

4: Desolder the 8 pin IC (10 pin on the V2). Again, if your iron is not small enough to do this reliably, you can break apart the IC, and then desolder the little leftover legs still attached to the PCB. Clean as much extra solder off as possible to avoid bridging to nearby traces.

5: Desolder then external switch wires. The switch can't be used anymore, so it's not needed. Simply bridge the solder pads where it was connected. This will make it "on" all the time. This needs to be done, trust me.

6: While you have the MMM apart, make some foam padding to protect the rest of the ICs from the case. Cut a strip of 1/8" thick foam and place it over the 3 motor solder connections. Cut two squares of foam and place it over the 2 power solder connections.

7: Reassemble the case.

Below are some pics:

V1 MMM showing components to remove:



V1 MMM showing mods completed (switch bridge graphically altered because I didn't have an actual picture):



V2 MMM showing mods complete (courtesy of Joe Ling - slightly altered for size):



A little schematic showing how the external UBEC could be attached:

[GT35R]

The BEC issue isn't related to the meltdown though is it??

I am happy to remove the parts (thanks BrianG), and it seems this can be done before or after failure.
But having the whole MMM combust on a plastic model is no appealing thought.
I would have guessed that was a separate issue due to overloading/current spikes, but
the setups listed don't appear to be that extreme (only going by what others have said).

So it has to be asked of those who have had a meltdown (their MMM that is) was it, quote
"More Than You Can Handle?"

[lincpimp]

Originally Posted by BrianG

They couldn't afford me TBH. Maybe parttime.

Nice to see that someone other than myself is "self-promoting"!

Most people just call me arrogant, though...

[BrianG]

GT35R: No, meltdowns are something (usually) totally different. That type of thing can happen to any ESC. The BEC issue is when it outputs 0v or close to 0v.

linc: Yeah, I suppose it did sound arrogant.

[ptt81]

Originally Posted by BrianG

GT35R: No, meltdowns are something (usually) totally different. That type of thing can happen to any ESC. The BEC issue is when it outputs 0v or close to 0v.

linc: Yeah, I suppose it did sound arrogant.

I was wondering what is the purpose of the bec mod above if it doesn't help with melt down problem? why is it not the same as using an external bec beside that it won't disable the internal bec