MMM, today is NOT our day x2...
 

Can you distinguish the similarities and differences between these two pictures?


http://i152.photobucket.com/albums/s...0/P7190025.jpg

and this one

http://i152.photobucket.com/albums/s...0/P7190024.jpg





It turns out, the difference is that one is my MMM, and the other is Ben's (brushlessboy16).
The similarities are that they both died on the same day, in the same exact way, with the same exact symptoms. Come to find out, the same exact component failed on each one! See the lower right corner, just to the left of the bottom bullet terminal. there is where there was once a component of some sort, but now is gone, from both MMMs, within 4 hours of each other, within 50 feet of each other.


The symptoms are as following: lost throttle during a race, and went to check it out. no LEDs on the MMM, but BEC still works. We both had servo and Rx power. Castle link does not see the MMM either.

My system is:

Hyper 7 conversion
4s NeuEnergy 5000mah 25c
14/46 gearing
standard diffs


Ben's is:

Revo 3.3 conversion
4s RC monster 5200mah 27c
17/38 gearing
Lst differentials
Proline VTR calibers.


Needless to say we are quite dissapointed with what happened, and hope it will be covered by castle when we call monday. here are some more pics:

http://i152.photobucket.com/albums/s...0719091830.jpg

http://i152.photobucket.com/albums/s...0719091832.jpg

http://i152.photobucket.com/albums/s...0/P7190027.jpg

http://i152.photobucket.com/albums/s...0/P7190028.jpg

Today truly sucked.. did well enough to bump up from the B to the A main and then this happens...

i dont want to have to switch to another brand.

here is a highlighted shot for better clarification


http://i152.photobucket.com/albums/s...010/hilite.png

Why do you guys need to call. Its easy, just fill out the on-line form and send it in with a copy of the receipt. Thats what I have always done. So is there any advantage to calling?

I'm guessing its the TVS... bad luck

@ hemiblas:

calling them up is always nice because A: they have a really friendly costumer service. these are not like the computer support people everybody dreads. the people who answer the phones at castle know what your talking about, and not searching a database for answers based on what you tell them. Also, I have called about a MMM before, and what the kind sir did was have a MMM sent out to me first, with a prepaid envelope to mail back my fried one, which is considerably faster on the consumer end than filling out forms, sending yours in, waiting 5 weeks, getting a new one in the mail when you almost forgot about RC all together.

@ Arct1k:

TVS? what is that? and i think it would be bad juju from the nitro crowd down Trax70 before bad luck... They make us do stop and goes, the marshalls always place it off the track pretending it flamed out, we're mocked for not having to tune 50 times a day, and they get quite pissy when we beat the pants off 'em

Stop and go is pretty standard and I have no issue with it...

Placing you off the track - Rev the nuts off it and give them a nice friction burn...

I love doing that. :) Scares the S out of some people

I know we tried some of that new no lead solder with one of our kit assemblers for the purpose of trying ROHS compliance and we had several components fall off of boards just like this.(we supply another company with our components and boards and they assemble them), We said screw it and switched back. Just about all the components you get these days are ROHS compliant (Removal Of Hazardous Substances). When we first started getting them in we had problems like this even assembling them at our shop. We also use water soluble flux (in house) which flows different than regular rosin flux. Some times it just seems the solder doesn't want to bond with the tinning on the component. We started a vibration test on the boards now to try and avoid this. We finally solved it, but I wonder if that could be going on here.

Jeff

Jeff, just curious, what company are you affiliated with?

Thompson Scale Co. in Houston, Texas.

Jeff

Jeff, do you race in/around Houston? Or go to Randy's?

Yes at Randys with Snellimin

TVS = Transient Voltage Suppressor (I think. It prevents harmful voltage spikes from damaging the caps) . I believe its actually located under the wires between the main + and - attachment points for the battery wires. Im sure a Castle dude will chime in sooner or later and identify the missing component- and then a solution/ redesign will be sought (MMM V4? you never know....).

Just got off the phone with Thomas, as I directed him to this thread. it is a tvs. it will be replaced/repaired under warranty..

Since mine is missing a solder pad it will be replaced, mikes is repairable...

3 week lead time..

Inductor -- not a TVS. That's part of the dc-dc converter for the MOSFET drive.

You must have hit something HARD to break the solder joints on that part....

Does landing a small double perfectly do that? was not a hard hit at all- i landed the jump and coasted around the next corner to set up for the next jump and then had no drive power:neutral:

I dont know where his car let go

if it was a hard hit why did the solder joint on this one component fail instead of any others?

Mine let go after rolling the triple. the track is a bit bumpy, and there is a pothole around the last turn that everybody loses their car in, but would this be like a sudden damage thing, or is every bit of vibration slowly killing it?

Not trying to bash on your products or anything, just curious of the cause...

I dont think the potholes are the problem, because there are 6 other people running Mamba monster systems that have no problems.

Are you sure you remembered to put shock oil in the shocks??? Ok just kidding.
Ya, we've given people trucks that can do 80mph and there are a lot of light poles out there that are afraid. I would hate to test the G forces involved being inside that truck during a race with potholes and jumps.

Is there any form of padding or cushioning underneath the MMMs, how are they mounted exactly?

No padding besides servo tape, both were mounted directly on the chassis. no funky angles or anything.

That particular component is one of the heavier of the small SMT parts on that board (made of ferrite.) We don't see many of them breaking like that.

So do we win a prize or something?:lol:

Cant wait till those new cases, eh pat?

yay! will we see those cases?

After talking about hitting light poles in my last post, my truck split in half after I hit a garbage can at about 35mph. The MMM still works great though. We really do put these things through a lot of abuse.

j57ltr is right on the money. RoHS is a pain but some oem corps wont look at you twice if you dont have it, especially europe and medical corps. i found soem vendors were passing off LF and PB components as the same. the end caps on the components wont take so well if your using a PB solder with LF components. the fact the solder pad resembles the shape of the end cap may indicate that this has happened, or handling contamination. not sure if a tvs is a moisture sensitive device in storage though? very strange. good luck with the RMA guys.

easy as...123revo

Again, not a TVS, that was an inductor. Handling isn't an issue -- these are not touched by hand at all -- and the reels are stored in their original packaging (which includes moisture metering) until they are placed on the pick and place machines. The manufacturing facility is maintained at less than 30% RH. After reflow, moisture isn't really an issue for that type of part.

This is a ROHS part, but I've yet to see another return with that part damaged or missing.

When I looked at the pics of your boards I was going to commend you for actually hand assembling these units. But you say these are all done on a pick and place? Everything on that board looks like is was hand soldered. I see no evidence of the glue usually used to hold the component in place before it is put through a wave solder station. If you look at the chip to the right that I believe is the driver for the BEC, two of the pins are almost soldered together (LTBRZ). Most of the components look to have more solder than I would expect to see from machine soldering. I am not bashing your product; in fact I really like the features and abuse they tolerate. But the component clearly came off because of a poor solder joint. Our A/D cards use inductors about the same physical size as the one on your board and we had problems like this as well. I actually made a vibration station to test our cards because of this problem. The larger components just need more heat to properly bond the solder. We had this on inductors and some of the SMT Xtals we use. I have also seen at least one other pic in this forum where a component has come off of the board.

Jeff

Vibration is one thing. These things are subjected to some serious abuse. Bottoming out from a 20ft jump is nothing to sneeze at.

Neither is 8 G's

Jeff

Edit: which is what we test at for 2 minutes.

yes it is if there is a guy that your in a battle with and he can do the same thing repeatedly with the exact same components and his truck.


Nothing against castle- i know that things happend and not blaming them- but when two cars fail for the the same component- even further the same chip on a component when there are nearly identical cars in each of the respective classes doing the same thing something is wrong.

someone else can have the soap box.

castle's replacing them. I'm not complaining...

Not buying it. No two cars will be exactly alike and the difference in suspension can change a gentle bottom-out to a not-so-gentle bottom out.

To be clear, I'm not saying this IS the case, just something to think about. Depending on the nature of the failure, the failure rate differences could be something as simple as a slight variation in component tolerance, temperature, ESC mounting, etc etc.

8 G's might be strong for vibration but it's not very much when you start talking about SHOCK.

True that.
Yeah its a really low chance of it happening as it did to Mike and myself though..:neutral:

Mount the escs upside down, so the chips arent subjected to the weight of the esc pressing down upon landing a big jump- same principle as having rear facing seats on a bus or train etc...

Granted it will look stupid though, but it might just work... :P

A vibratory table will sustain forces for a much longer time. A single shock load may be higher but a shaker table will tell you. Since implementing this test we have yet to have a single failure for “lost” components in the field. A ferrite inductor isn't really that heavy (I’ll weigh some in the morning), it may be heavier than the Cap that's sitting next to it but because of the way they broke you can clearly see that the solder joint was not a good one. It happens; they are fixing it under warranty. Excellent customer service as I have seen in the past. I am not saying anything bad about them or their process, hell we are a small company and we screw up all the time. When we find it we fix it and put in place measures so that it doesn't happen again. I am not even saying they made a mistake, a solder joint can get past the best of us, even with a 10X Loupe. And with some of the new solder and components out there it is a problem until you get used to it. I have soldered HPM solder for tools used in the oil field industry. I can freehand any component you put in front of me surface mount a PLCC chip not a problem, SC70 transistor, you betcha, leadless packages all day long. I have done solder inspection till I am blue in the face, it’s a bad solder joint. No big deal. You guys are always blaming the user I don’t understand it.

Jeff

J57:

Wave solder? Is this the 80s?

We use 100% reflow soldering -- there is no wave soldering done. You couldn't wave solder these parts anyway, they are much too small and placed too densely for wave.

The joints look a little grainy because there is a silicone conformal coating over the whole board. Those are beautiful solder joints -- not a cold joint in the bunch.

(Remember, we are 100% lead free, so the solder joints are not as shiny nor as strong as leaded solder joints... but we have no voiding, and 100% of the solder joints are inspected by AOI prior to conformal coating. -- We are lead free because we sell worldwide, and we cannot sell items containing lead in Europe...)

The joints in the picture failed, not because of poor joints, but because of shock. I imagine (even though we didn't see the parts) that the end caps on the inductor failed, the part rotated, and tore the solder joints cleanly. It's pretty obviously a torn joint. A cold joint would have shown voids, not a cleanly torn surface.

Shock can be enormous in these cars -- I've seen 10ga wires ripped in half just from their own weight (think about how many Gs that is!!), 96 mil thick FR-4 circuit boards bent 90 degrees, circuit boards where EVERY pad on one side of the board is torn off the FR-4... you name it, we've seen it. (And 8Gs is nothing... We routinely see forces over 70Gs in RC cars.)

So soldering is very important to us. We use a Heller 7 zone full convection oven (accurate to +- 1 degree in every zone, and specifically designed for lead-free operation), and we profile every batch. We use a very sophisticated AOI system that literally inspects every single solder joint on every single board we produce.

We use a VERY expensive tin/copper/silver solder formulation for our solder paste (printed,) bar solder and wire solder. This is a much stronger (physically) formulation than SN100 (100% tin) which is used in most lead-free industries today. It's still not as strong as 60/40 -- but it's close.

We take quality very seriously -- we aren't perfect (see MMM V1...), but we utilize tools that make the quality easy to maintain, and we check our quality continuously.

Castle isn't a basement operation - - we have some of the most sophisticated equipment in the world in our surface mount line (including the fastest and most accurate chipshooter available today), and we produce around 30,000 controllers a month.