MCB-E ("blue box") Issues, Post up your experiences

[Seaharrierman]

I'm having the rudder and nose wheel steer issue on my Flightline 1600mm Corsair. I fitted a Spektrum AR9020. I want to use a sound unit as well as a hobby eagle A3S3 gyro so need the extra channels. I use a DX9 Tx what do i do?

[Skosh25]

I have the Corsair, T-33 and L-39. No issues so far. Corsair has over 100 flights on it. All stock and running Futaba.

[mshagg]

Just to add a data point. The rudder on my Avanti demonstrated some uncommanded inputs until I bypassed the multi function box for that channel. Interestingly the nose wheel steering didn't display the symptoms.

And recently just had issues develop on an aileron servo on the F22, which was twitching from one end point to the othet. Bypassed the multi function box for flap and aileron servos, so far so good (thanks for putting the retracts in the fuse!).

The Avanti runs an AR636 Rx on the stock BEC, the F22 is running an Frsky S6R on the stock BEC (the joys of open source radios!).

Neither faults have caused crashes and have presented in preflight inspections.

[Johnnyrabuse]

I've got at least a dozen ships with blue boxes rule one

Beware the loose receiver to wire issue they can vibrate loose or get bumped by a battery

I've never lost a jet to a bad blue box I have lost them because of cheap receivers off brand with weak antenna or inadequate voltage outputs causing fades holds and brownouts

I don't use thirty dollar or less receivers in any ship that cost over 300 bucks

Gains on gyros set too high also burn out servos

So it's likely not a blue box issue

[SBN]

Alpha , you might want to know about this...

I bought a Freewing L-39 from MotionRC and expected a nice airplane that worked out of the box.

The problems started when i connected my rx to the MCB-E box.

4 servos was twitchy and i got RSSI critical @ 40 meters and Telemetry lost @ 45 meters away from the radio. Mind you it was not in range test mode. It was at full transmitter power. A interesting thing, servos stopped twitching 3-4min after power on. But still problems with rx/tx.

The rx is a Frsky S8R running FCC firmware that has been working perfect in another plane just before i but it in my L-39. My TX is a Radiomaster TX16s that is also working great with all my other models and with the S8R rx before i put it in the L-39.

Funny thing was that the twitchy servos stopped witching when i moved the rx away from the MCB-E. If i placed the rx just behind the MCB the servos started twitching again.

After a lot of testing i contacted MotionRC support and i was a little shocked with the replay i got.

In short they told me to bypass the MCB--E box to fix the problems!

This is what they wrote:

"There has been a long investigation into the mcb box that Freewing has been conducting to figure out these isolated incidents. There hasn't been any real concrete evidence on the cause but it's believed that the mcb box doesn't play to well with certain radios/rx's. The mcb box at the end of the day is just a fancy Y harness. If you're having issues with the mcb it's best advised to have everything plugged directly into the receiver via extensions/ Y harnesses as another mcb box would likely cause the same thing you're experiencing with your radio/rx setup."

They are telling me that a new MCB-E box will not fix my problems. And that the MCB-E box does not play well with all radio systems!

Then i responded that i was shocked that the product i bought as a complete airplane that only need rx and battery is not working.

Now i got a respons that they will send me a new MCB-E box, but wait a minute didn't they just say that a new MCB-E will not fix my problem?

I told support to keep the MCB-E box, i will not risk my lovely L-39 to a MCB-E box that might work or might not work.

What i did ask for was i solution for controling the lights in my L-39 with out the use of the MCB-E. I got no response...

I ended up taking out the MCB-E and replacing the harness from end to end. Now my L-39 is flying with the S8R rx with no range problems and no servos twitching.

At the end of the day, my L-39 is now working with out the MCB-E box.

My problem is that i bought a product that was supposed to work out of the box, but it didn't and MotionRC know about the problems but they are still selling the product that they know does not work on some radio systems.

For the fun of it, i did a test with my Hitec Aurora 9 and a Optima 7 rx before i tok the MCB-E out of the airplane. Funny thing was the servos stopped twitching, and the retracts stopped working. So no joy there. Both my radio systems failed with the MCB-E box in different ways. Motionrc/Freewing knows that the product is a bit of hit and mis...

Why does MotionRC not mention this on the product page?

And way are they selling this MCB-E box with out warnings that this might not work with all radio systems?

And ho is paying me for fixing a problem that MotionRC/Freewing is supposed to fix?

For the record, MotionRC never sent me a new MCB-E box. And my landing lights is still not working.

Dont get me wrong, i love my Freewing L-39. It is really nice airplane to fly.

Freewing airplanes are way too expensive to not work out of the box.

My 2 cents

Simon

[xviper]

And my landing lights is still not working.

The control box is not just a fancy "Y". It's also the light controller and even gear sequencer for other applications. If you want the lights to work, you need to use the control box or get a separate light control box. The other caveat is that in order to work the lights thru the control box, something else has to be plugged into it to provide power. I bypass the critical stuff like AIL and ELE, leaving everything else plugged in to the box. I use Spektrum but you might try that and move the RX or the box or both to create more distance between the two.

[radfordc]

[QUOTE=jaldendifer;n202207]Motion sent another box, and I flew it approx 15 or more flights no issues, until one day after initial flight went to connect new batts and heard pop. I have no idea what happened, but every servo except the two main gears, died. no smoke, burnt smell or any indication of short could be found. Motor worked fine. /QUOTE]

I had an eerily similar occurrence on a different Freewing jet with a different "blue box". I had a 70mm BAE Hawk that had flown successfully many times. On the day I had flown two good flights and was starting the third. As soon as I added throttle I heard a pop and the motor stopped. Then smoke started pouring out the tail pipe. The ESC is completely vaporized. I found some of the strangest stuff I've ever seen. Half of the channels on my FrSky Rx are dead....4 work, 4 don't. Four out of eight servos were completely dead and the other four seem fine. All three retract units are dead. I assume that there was an overvoltage that got through to some of the channels but not all?

MRC basically told me to suck eggs when I contacted them. (What they actually said was that it was out of warranty and they wouldn't do anything).

[SBN]

The control box is not just a fancy "Y". It's also the light controller and even gear sequencer for other applications. If you want the lights to work, you need to use the control box or get a separate light control box. The other caveat is that in order to work the lights thru the control box, something else has to be plugged into it to provide power. I bypass the critical stuff like AIL and ELE, leaving everything else plugged in to the box. I use Spektrum but you might try that and move the RX or the box or both to create more distance between the two.

Thanks xviper, i do know about all that.

I am trying to make a point and get MotionRC to step up and fix this. Not only for me, but for all of us.

I know i can do the lights with the MCB-E, but i don't want that thing in my plane. I lost range to the point of not being able to fly the thing when i had that box in the plane.

Again, i want MotionRC to step up and fix this. I paid for a working L-39. I did not get that and the tech support did not fix it...

Simon

[xviper]

This topic started nearly 2 years ago and we continue to have input from those who have issues. As for a "fix" being addressed ......................... you know the old saying, "Time will tell". Well, time has passed. What does that tell you?

[SBN]

This topic started nearly 2 years ago and we continue to have input from those who have issues. As for a "fix" being addressed ......................... you know the old saying, "Time will tell". Well, time has passed. What does that tell you?

It is telling me that my Freewing L-39 might be my first and last plane from MotionRC...

[xviper]

It is telling me that my Freewing L-39 might be my first and last plane from MotionRC...

Well, that's one way to look at it. However, in my mind, I know the limitations of these planes (control boxes being one), so I know when, where and what to by-pass. Freewing has so many exceptional models that I won't handicap my selection process purely on the basis of one or two things that can be easily bypassed. No model is perfect and we're beginning to see that in other different brands. The current example being the really pricey Eflite Draco. The hype was and still is unbelievable. They sold out the first batch in 35 minutes. Now were beginning to see issues with loose horizontal stab, really hard to remove wing pins, cockpit dash that gaters in 2 minutes in the sun, bouncy landings. Will that make me eliminate is from my list? Hell, no. I can't wait to get mine from the second batch.

[SBN]

Well, that's one way to look at it. However, in my mind, I know the limitations of these planes (control boxes being one), so I know when, where and what to by-pass. Freewing has so many exceptional models that I won't handicap my selection process purely on the basis of one or two things that can be easily bypassed. No model is perfect and we're beginning to see that in other different brands. The current example being the really pricey Eflite Draco. The hype was and still is unbelievable. They sold out the first batch in 35 minutes. Now were beginning to see issues with loose horizontal stab, really hard to remove wing pins, cockpit dash that gaters in 2 minutes in the sun, bouncy landings. Will that make me eliminate is from my list? Hell, no. I can't wait to get mine from the second batch.

That is your choice, i am normally not a foamy pilot, i fly mostly balsa or composit and i almost never buy a PNP airplane. And when/if i buy a PNP i expect it to be exactly that PNP.

The L-39 was a test for me, and it went bad.

What really pissed me off was that MRC support closed my ticket without a solution to fix my problems with this MCB-E box. I was lucky that the L-39 does not have doors for the wheels that need a sequencer. It was easy for me to make a new harness with out the MCB-E box. But doing that on a PNP plane feels wrong. It is not what i am paying for.

I agree with you that MRC has a lot of nice looking airplanes, but my experience with this L-39 has put me off from buying more airplanes from MRC/Freewing.

[xviper]

That is your choice, i am normally not a foamy pilot, i fly mostly balsa or composit and i almost never buy a PNP airplane. And when/if i buy a PNP i expect it to be exactly that PNP.

The L-39 was a test for me, and it went bad.

What really pissed me off was that MRC support closed my ticket without a solution to fix my problems with this MCB-E box. I was lucky that the L-39 does not have doors for the wheels that need a sequencer. It was easy for me to make a new harness with out the MCB-E box. But doing that on a PNP plane feels wrong. It is not what i am paying for.

I agree with you that MRC has a lot of nice looking airplanes, but my experience with this L-39 has put me off from buying more airplanes from MRC/Freewing.

I don't fault you for your feelings on the matter. You've been stung and it left a bad taste. I'm the same with Ford. They screwed me over when I was a young man and I've purchased nearly 40 new and used vehicles over the subsequent 54 years and not a single one of them was ever a Ford again.

[Gilatrout]

T33. Intermittent nose gear retract failure. Sometimes it fails to come down. Mains always work

Bypassed blue box for nose gear only and now it's 100% reliable.

[dblewis76]

I just bought the FreeWing F/A-18C Hornet. I have the Spektrum DX9 and AR10100T receiver with SRXL2 output to the Aura 8 gyro. I have everything connected and working except the BB is controlling the nose wheel steering servo when the gear are up. Any thoughts on TX or Aura 8 configuration that may cause this or is it an issue with the BB? Yes, I could put the nose wheel steering on a separate RX channel and mix with gear up/down, but having paid for a device to do this, it doesn't seem right.

[JDill]

I thought from the beginning that the MCB-E should be powered directly from the BEC, with a separate feed from the BEC to power the receiver, and then single leads from the receiver signal pins to the MCB-E. Why feed the power for everything through the receiver? It's not what I do when I install an external BEC on a model. So I "modded" mine in this way on the L-39 and am in the process of doing the same on my new OV-10 Bronco.

No problems at all on the L-39 with the mods. Maybe it would have been OK with out them, of course, but it makes me feel better 🙂

Oh, and I opened up the MCB-E box in my OV-10 and there's an ON/OFF switch in there that looks like it was soldered in after manufacture. It's in the ON position. Wonder what that's for?

[Evan D]

Did you take a picture of the switch by chance? I agree that electrically it would be better to power the MCBe directly especially if you use it to the max connecting everything to it, or a Y to it and the receiver. But that said I usually bypass most of the MCBe and I have never had a problem with one, knock on wood.

[kallend]

Be aware that if the receiver and MCBe are powered directly AND the -ve from the receiver is also connected to the MCBe by way of the servo leads, you have created a ground loop. It probably won't be an issue but in general ground loops are best avoided as potentially they can cause interference.

[JDill]

Did you take a picture of the switch by chance? I agree that electrically it would be better to power the MCBe directly especially if you use it to the max connecting everything to it, or a Y to it and the receiver. But that said I usually bypass most of the MCBe and I have never had a problem with one, knock on wood.

Sorry, no photo and the box is buried in the OV-10 now. I looked at the circuit board traces it was soldered to but couldn't tell what it would affect. The switch itself was like the attachment.

[JDill]

Be aware that if the receiver and MCBe are powered directly AND the from the receiver is also connected to the MCBe by way of the servo leads, you have created a ground loop. It probably won't be an issue but in general ground loops are best avoided as potentially they can cause interference.

Thanks for making this point as I didn't state it in my post, and it's a valid concern. To avoid this the only ground wires (black leads) on my install from the BEC are on the 2 plugs (I created a Y connector), one to the receiver and one to the MCB-E box. All connections between the receiver and MCB-E are single leads for the signal channels, so no ground leads.