MMM took out rx and servos

[secondgear]

Ran 6S for the first time on my E-Revo. NeuCastle 2200kv motor 18/68.

Ran really nice and made nice power, but I ran into problems.

5 minutes into the run, the truck stopped responding.
Disconnected the battery and started looking around for what failed.
Found that the BEC on the MMM had failed. The RX was burnt out from over voltage. Both servos had failed.

The only thing I can see that caused this is the BEC failing and sending pack voltage through the rx to the sevos. Assuming the rx took the voltage, the servos failed and drew more current which took out the rx.

Anyways, this MMM was purchased back in 2008.
Is Castle replacing these older units? I assume that this is V1 or V2

[secondgear]

Also, I updated the firmware earlier this week to the latest non beta version.

[suicideneil]

Yep, if its a V1 or V2 ( wires for batt and motor side, or bullets for batt & motor side ) its a free replacement. Not much that can be done for your servos or rx saddly- BrianG has a design for a failsafe of sorts to prevent the same thing happening again ( stop full voltage being sent to the rx, even if the BEC fails )..

[secondgear]

Do I just send it in to Castle, or can a lhs take care of the return?

[Arct1k]

Normally direct with castle unles lhs will do that.

[BrianG]

Originally Posted by secondgear

...The RX was burnt out from over voltage. Both servos had failed.

The only thing I can see that caused this is the BEC failing and sending pack voltage through the rx to the sevos. Assuming the rx took the voltage, the servos failed and drew more current which took out the rx...

That sucks. That happened to me too, except it was an external BEC. I was able to fix both the rx and servo though.

If the actual rx circuitry survived the overvoltage, then the rx's PCB traces connecting the power and/or ground pins may have simply burnt from overcurrent. If this is the case, try soldering a wire across all the power (middle) pins and another wire across the ground pins.

On the servos, I assume you are using stock Trx servos? Probably not worth fixing, but sometimes you can pick up the driver board for much less than a whole servo. Then it's just a matter of removing the old board and soldering in a new one. In my case, it was a $100+ servo that blew so it was worth it for a new driver board for $26.

Unfortunately, this type of failure can happen to ANY switching BEC. It's just how they work. Hope things turn out good for you and are able to get things fixed with minimal cash outlay!

[secondgear]

Thanks for the input, guys.

The components on the board of the rx are cooked.
I've got a new 2.4GHz module system for my Hitec tx on the way anyways that uses high voltage receivers good to 16V, so I should be good there. The fact that the rx is under $20 makes it easy to keep spares on hand as well.

I'll have some servos on order shortly as well. Was just hoping that the truck would be running longer before anything like this happened...

[suicideneil]

$20 receivers? Wowzers- what radio is it you're using again?..

[secondgear]

Hitec Agressor.

The module I've ordered will let me use the cheap receivers.

[secondgear]

I've seen it work with other guys using a 3PK.
Normally, it's used for planes, but they've found it to work really good for surface vehicles.

This video is what peaked my interest.
http://www.youtube.com/watch?v=CkZz8...9&index=15

[suicideneil]

I'll have to watch the video at home later. A few people have commented how strange it is that aircraft receivers, often with multiple channels, are cheaper than the ground receivers; I use a Speky DX6i & the 6-8 channel rxs are about £35-40, vs £40-80 for ground models with only 2-4 channels at most..

[magman]

Originally Posted by suicideneil

I'll have to watch the video at home later. A few people have commented how strange it is that aircraft receivers, often with multiple channels, are cheaper than the ground receivers; I use a Speky DX6i & the 6-8 channel rxs are about £35-40, vs £40-80 for ground models with only 2-4 channels at most..

Wonder if they have a rx that would work with the spektrum series of controllers

[secondgear]

It will for sure not work with the Spektrum txs. I would be all over it if I could.

There are compatible rxs for Spektrum from China now.
Flew a plane for the first time with one yesterday with my DX7. All the range you need for a park flyer at $15 a pop.

[suicideneil]

Argh, stop being a tease- what rxs from China work with the DX7? Too late for me really, but for future reference atleast..

[secondgear]

http://hobbyking.com/hobbyking/store...&ParentCat=190

The trick is finding them in stock...