Dead Mamba XL?
 

Little help here guys. I converted an Losi XXL to brushless last month with a 1717 and a MMM. Ran fine for a few weeks and one day it just wouldn't turn on. Ok, no biggie. I got a used Mamba XL on eBay a few weeks ago. Powered on and worked fine. Took it to the park this afternoon for it's first run since the new ESC. Ran for about 30 seconds then just died. WTH. Swapped lipos and no change. Didn't even get a spark when connecting the battery. The fan is running and the servo still turns. Took it home and tried other batteries. Still nothing. Unplugged everything and just had the ESC on the RX. Still nothing. Had just about given up but decided to connect to Castle Link and for some reason it connected. The software noticed the Mamba XL was connected. Even updated firmware. Saved the settings and tried to plug in the battery. Same thing. I give up. Any suggestions?

MMM - did you check the switch ( cut off switch, twist wires together )?

MMXL - does the motor chime when connected, tried a different motor, checked the wiring over for cold joints that may have popped? Does the esc, motor or wiring get warm when you try giving it throttle?

Very odd..

You haven't any exposed connector ore any thing like that? very important to use heat shrink.

Can you see any visual damage on any of the capacitor?


if Castle want you to ship it in its very important that you also include the motor.

Seems to me the capacitors are the problem with these, but I could be way off.

Ok so the MMM won't even power the RX so that just seems dead. With the XL it doesnt chime the motor at all. No spark when I connect the battery. It's odd. BUT it looks like the lights are working and I am getting the correct lights when I hit throttle and brake. My servo works fine. The RX has to be working fine if I can still steer the servo. Nothing gets warm. All the connectors have heat shrink.

Hopefully it's just the motor and not the ESC. Could shortening the motor and ESC wires have anything to do with this?

Only if you do a terrible soldering job when re-installing the connectors ( cold joints in the bullets ), other no- shorter wires the better.

You could be on to something. I did have a hard time trying to solder the XL wires since they were so damn big. I'll check when I get home. But that wouldn't explain why it actually ran for a minute before it stopped.

What do you mean by "cold joints in the bullets"?

Cold solder joints where the bullet connectors ( motor > esc ) are attached to the wires; the solder melts inside the cup just fine, but it doesnt stick to the metal. If you tug the wire, it comes out with a cup-shaped plug of solder on the end and the inside of the cup is clean as a whistle inside ( like a cup of ice- warm the cup and the ice drops out in one solid lump ).

Otherwise I'm fresh out of ideas..

Ah ok thanks for clearing that up.

I assume you used batteries that worked perfectly fine when you tried this out? How many cells in total did you use on the MMM and the XL, and what kind of batteries (C rating, mah etc.)

Also, what servo did you use on the previous setup with the MMM? Did you have a BEC?

Did you test the ESC's with another motor by the way?

Batteries were freshly charged TP 6s 5000mah 45c. Tried the other lipos and it looks like that isnt the problem. Servo is a JR DS8711 and it works fine. Didnt have another ESC to test the motor so I took it down to my LHS. Same resistance going through the motor wires so it's ok. Found out the white motor wire wasn't putting out anything. I'm going to re-solder it again today just to make sure butit looks like I'll be sending it out to CC and be in the waiting game for a month.

I'm glad you figured it out. Grats!

In my previous reply I was going to suggest that one of the motor wires might have experienced a malfunction, caused by an issue with a tiny portion of those tiny wires inside the motor wire itself. Like a tiny, tiny portion of the yellow wires thousand of strings suddenly pushed the electricity back instead of passing it on. :rules:

Weird that something like that might actually have happened lol.

the soldering job on these HV escs is important. when you have built up resistance from bad or cold joints, the power has to go somewhere, right?

i wrench at my lhs to help out with repairs when they're backed up, and I really try to emphasize to all of the customers how important good joints on the esc and batteries are when they buy some of these high powered systems.


i can't tell you how many escs and batteries i have to re-solder at my lhs from customers who think that just because they see solder on the wire it's fine.....it HAS to flow through the wire completely to be effective...and you really need to use the right kind of solder and atleast a 60W iron.

check youtube for videos. it will do wonders for the life of many of these kinds of escs.

Would silver bearing rosin core solder be a good choice? That's what I've always used.

i've found that a good 40/60 or 63/37 mix works the best. my personal favorite is the 63/37, but the 40/60 is what is most generally accepted and the most common to find.

anything that's lead free and doesn't have silver in it will be a PITA to solder. that was my mistake when i first started soldering. also, try to get at least a 60w iron or even a 150/230w soldering gun.

my ideal soldering setup:
radioshack 150/230w soldering gun
63/37 rosin core solder
radioshack flux paste, which helps the solder flow better (i only use it occasionally, if needed)
deans ultra plugs (or the hobbyking ones with ridges)
a simple cheap locking plier tool to hold the plug in place
a damp washcloth or sponge to clean the soldering gun tip after each use (very important)
40w solder suctioner if i'm soldering small things such as circuit boards

once i got the proper solder and a proper soldering iron, my solder joints improved DRASTICALLY. i went from having giant solder globs that would only stay put 50% of the time and would often not last during use due to them breaking loose at high current.
now, my solder joints look professional and are as good, if not, better than pre-soldered packs that you can buy from the hobby store.