New MGM problem?
 

Finally got my 16024 that I had the repair difficulties with installed in my Savage today. It's acting weird though. After I plug my batts in (6s) It starts beeping the error beeps (the constant timed one) at me WHETHER THE CONTROLLER IS ON OR OFF!

I've never experienced anything like this. Any ideas?

I'll update here. I tracked it down to a bad receiver. Replaced with another one. Was operating two servos fine with a ubec for power. As soon as I turned it back on after plugging the mgm into the receiver, but without power to the Mgm, the MGM started beeping again and smoked the receiver:035:

That's two hundred dollar receivers in the last two days this MGM smoked. This is AFTER getting it back from repair. This MGM just doesn't like me.:mad:1

To be clear, you are removing the red wire from the throttle cable right?

No, this is an opto controller.

I think you have to anyway, but I am probably wrong. I have heard of the MGM's smoking receivers by sending the total voltage to them. Try it. I would try it with a cheap AM receiver or something though...

Everybody else I've seen who has tried removing the red on an opto MGM ended up with a non-working controller. This controller also worked previously without removing red and without frying a receiver.

Yeah, from I've heard, if the internal bec goes, it sends the battery voltage to the receiver. Don't feel too badly, I got a 16016 and hardly got to run it. It's going back to MGM via Mike tomorrow.

Also guys, don't forget that I didn't have power going to the controller, only the radio system.

That sucks on your MGM. Unfortunately, be ready for a wait. This one, though does not have a BEC.

Well then, if you only had your UBEC hooked up, I would suggest checking the output of the UBEC. If it is faulty, it can send full battery voltage as well...

Forgot to mention that voltage at the receiver was 5.57-5.58 the whole time (I have a Sensor). The transceiver still powers up and connects with my transmitter (for those unfamiliar with the Sensor, there is aubible and visible confirmation of events such as these), there just isn't any transfer of signal to the servos. Well there was, until I plugged in my MGM.

Sounds like the MGM controllers are more of a burden than an investment.:002:

Hasn't been fun for me. In 9 months of owning this, I've had 10 minutes of run time. It also looks like it has cost me $200 worth of receivers on top of the $325 I bought it for.

Seriously man, I feel sorry for you. I've had stuff like this happen to me with electronics i've bought, not fun. :019:

Are the receivers salvageable? There might be a protection device inside that you may be able to replace to breathe new life...

What radio are you running?

Perhaps, I am sending them to Nomadio for repair, so it will probably be less than $100 each. That is just the replacement cost.

The Sensor.

The only thing I came up with last night is that the MGM was trying to power everything through the receiver plug, pulled too much current, and poof. But the question is why?

If the ESC's BEC output voltage is higher than the UBEC voltage, the current will come from the ESC BEC and the UBEC won't do anything.

Once again, this is an opto controller, no internal BEC.

The real shame of it is that the Compro looks like such a bad a$$ controller and it's appears to be built well. I feel for you. It sucks to have problems like this with a piece of electronics that is on the pricey side.

Sorry, I guess I missed the first time you said that. My bad.

Question: What exactly does opto-isolation mean for R/C? I know what it means in the electronics world, but am having a hard time firguring out how it relates to BEC use...

No problem at all and I appreciate your trying to suggest an answer. I just wanted to re-post it for clarity's sake.

As for the second part, I don't have a clue. I'm still trying to figure out this mystery before I do any more figuring.

OK, where are the mods! I now need to know how opto-coupling applies to R/C!

However the BEC is coupled, it seems odd that the receiver is fine until you hook the MGM to it (if I read the problem correctly). It just sounds like the receiver is getting more voltage (somehow) than it can handle and blows up.

try this, just for trouble shooting. Measure the voltage at the receiver, maybe use some small wire to hook up in the there. Then use a multimeter on that, just don't let the wires touch!! :026:

My Sensor read a constant 5.57-5.58 for receiver voltage with the ubec. It has never been wrong (I love this radio). Just for giggles, I hooked up a receiver pack and got a reading of 6.78on the display. I then took a multimeter to the pack and got a reading of 6.82.

Well, something has to be killing your receivers. I don't know how often the radio samples the voltage which it simply isn't picking up, maybe there are spikes of voltage. Although I can't imagine why...

Let me help you out:

Opto Isolation as relating to R/C is the same OI as in all other electronics pertaining to OI. OI allows a low voltage/power circuit to control a much higher voltage/power circuit. Your Opto-ESC contains two basic parts, the Control side and the Power side. Between the two sides are three OI Semi-Conductors. Three because the ESC has three phases, usually. Each OI SC contains an Infrared LED and an Infrared Phototransistor. The Control side of the Opto-ESC simply turns on each IR LED in sequence, which turns on each IR PT in sequence, which activates each phase of the Power side, yes, in sequence. There is absolutely no hard-wired connection between the Control side and the Power side of the Opto-ESC thus you need a reciever pack to supply power to the Control side of the Opto-ESC as well as the reciever and servos.

Thank you. That does not have anything to do with the BEC circuit though! I then take it OI has nothing to do with the BEC...

You and me both!!

As a recap of op:
The MGM is giving the error beeps with or without the switch on. What really trips me out is that if I have one of the power leads bullet plugs pulled out of the MGM, it still gives me the beeps!

So like I said midway through this thread, it's pulling it's juice to do that through the receiver.

I think I'm gonna sell this damn thing and give up on running 6s and get a Quark!

OK, that symptom sounds familiar. When I first got my MM ESC, I wanted to test it out and set up some basic programming. So, I put in a receiver pack into the RX and plugged in the MM controller cable without removing the red wire and no main battery pack. As soon as I did this, I heard arming tones from the motor! And, like you, it didn't matter what position the switch was in.

All I did was remove the rx pack and it worked fine. It also worked fine if I used the rx pack but removed the red wire in the throttle cable. This sounds A LOT like what you are seeing, but I didn't blow the ESC or receiver.

What might be happening is the ESC is pulling power to arm the motor through the throttle cable. It would then make sense that this would blow receivers because the PCB traces aren't designed to handle that kind of current.

I'm sorry if I wasn't clear enough before. OI relates to BEC in that OI ESC's do NOT have BEC capability at all if they are truely OI. This is because the main battery is not connected to anything except for the Power Side of the OI ESC. There is no physical connection between the Power Side of the OI ESC and the rest of the system. This is why you need a second battery (reciever pack) to power EVERYTHING including the OI ESC itself.