I have a faulty ESC on an AVIOS Hercules c-130

[alex4orly]

If I want to replace that ESC, must I replace all the 4 if the one I can get is a different make / type?

Cheers

[xviper]

It's possible so long as it's the same amps and you disable the BEC if you use a non-opto ESC. If you do use an ESC with a built in BEC, just pull out the red middle wire from the receiver plug. It's always better to use the exact same brand and type of ESC, however, even with those, there will be slight variations between one unit to another. I've used different brands (but the same amps) of ESCs on the same multi and it seems to work OK. You should try to get HobbyKing to send you a free replacement since it was this way out of the box.
In your post in the "other" thread, you said you want to replace just the one with a 20A ESC. Since the stock ESCs are 18A, it's a risk but I think you could give it a try. You may not have any really bad adverse effects in doing that but if you're going to buy a new one, why not get an 18A one from HobbyKing? Pull out the bad ESC and see exactly what the brand name is and get it from HobbyKing.

[alex4orly]

Hello again,

Well, I will repeat my "Story" from the other thread.

The wiring from the Rx comes into the wing in Black/White wires. It goes to the inner mottor and at that point splits like a "Y" junction to continue to the outer motor that shows the problem.
This pair goes to the ESC and is soldered directly into it. Usually, the ESC gets a signal cable including Red, but this is not the case here.

The POWER to the ESC goes in by a pair of RED/BLACk and also soldered directly into the ESC. Obviously, the RED is also feeding power into the ESC.
The existing ESC has no brand on it, nor can I find a spare ESC of that type at Hobbyking, but I have spare Turnigy 18A ESC which I intend trying.

But, I suspect it is maybe not the ESC itself, but the "Y" junction, where maybe the black signal wire is not soldered properly, so I intend to bypass that junction and go to the ESC directly. What makes me think that this maybe the problem, is that the ESC gets the throttle command to spool up by the WHITE / Signal wire.

Will report the outcome

Many thanks again

[xviper]

Alex, you are getting a couple things mixed up in your description. I don't know if this is because that's the way you understand it to be or if you are just using the wrong description for various things. Nevertheless, it's hard to follow what's going on with your plane.
1. The red and black wires going into each ESC is POWER and GROUND from the flight battery. I think you've got that right. Then you say "RED is also feeding power into the ESC". By "also", you are implying that power is being fed to something else. What is the "something else" you believe is being supplied with power?
2.The black and white wires between the RX and the ESCs are the throttle signal wire (white) and the throttle ground (black). Normally, there is a RED wire and this is sending power back to the RX to give it power. RED is not a signal wire and is not needed on this plane because all the ESCs are "OPTO" ESCs (no BECs within). A single external BEC is what provides the RX with power and that is wired to the battery lead. The black wire is not a signal wire. It is a ground.
3 Yes, do try the 18A Turnigy ESC that you have BUT, if it has a red wire, either cut that wire or pull that pin out of the plug and tape it so it doesn't contact anything. Previously, you said you had a 20A ESC to try.

[mshagg]

Only other thing to be mindful of are potential differences in the ESC setup - timing, startup power, brake etc. Changing the setups with beeps and stick inputs isnt fun on multi engine planes. On the plus side it wont be the end of the world with a 4 engine beast, on the down side it wont be that easy to diagnose lol. Agree that getting an exact replacement would be Plan A, with a substitute being Plan B.

[alex4orly]

Hi xviper,

I will start from the end - problem resolved! The culprit was the ESC. Now, a few comments:

1) I am a certified electrician, or at least was one during my working life.
2) I had incidents in the past, when I used technical terms, GROUND, SIGNAL etc... and people asked me to specify wire colours...
3) SInce that time and due to not knowing who are the members I am addressing my queries to and what their background is, I switched to talking in COLOURS....
4) Yes, I know that the pword DOES NOT go from the Rx into the ESC, but the other way around. When I said - the wire going into the ESC, I meant - it is COMMING from the RX into the ESC, I didn't mean that this is the direction the power signal goes. In this case here, the POWER to the RX to feed itself and the servos comes from the BEC of course.
5) Hobbyking and most other distributors for our hobby, are just pimps / box pushers. THey do have some spare parts, but only for the main components. AT present, I am waiting since March for replacement motor for this model, as the initial thought was that the motor is faulty... Lucky I got sick of waiting and started thinking, that maybe the motor itself is NOT the problem. I reached this conclusion after swapping two of the motors and seeing that the problem remains in the same place where it was found at the start.

So, I checked first the wire (Black / Ground) to the location, see attached Pic1 - which clearly shows the welding is nice and clean, so the problem is not that and had to be the ESC itself. The 20A I had was too big, even the 18A which I used was way to big to fit into the gap under the motor mount. Please see Pic2 of the original ESC next to the one replacing it. I am used to ESC including a capacitor to overcome spikes, in this case, that ESC doesn't have one... They cut whatever corners they could cut.

Pic3 shows the cut I had to make in the foam nacelle to enable th ereplacement exercise, pic4 shows the new ESC in place after I ended up rewiring and soldering. I used the 3 pins of the old ESC so that I could connect them onto the exisiting motor pins. Pic5 is the final setup before gluing back the part I had to cut.

I re-synced the ESC, took the bird out and - it was just all good, open throttle, the 4 motors start and run ok and the model tracks streight ahead...

Now, to conclude this saga:

1) Looking inside the fuselage with all the mess of wires inside, how can I trust this machine? I read on the various forums crash stories, not one...
2) What if one of my landing gears is faulty? Where do I get a new sequencer for the doors? I could not find any details
3) I tried contactinc AVIOS, but the only option I found was on Facebook
4) I tried that, the auto response was to contact Hobbyking for any technical support - nice arranement I must say...

So, thank you and mshugg for your suggestions and feedback.

Now, I have to check the lateral balance and adjust if the bigger ESC is adding too much to that wing. Will also check now the CG and see if I can use a larger battery which some people suggested that it made it a bit nose heavy ...

Will report back after I get to maiden it.

Cheers

[xviper]

Glad you got it sorted out (on the most part). That replacement ESC is huge by comparison. Don't forget to disable the red wire (of the triple wire set) coming out of the ESC or you'll have dual power for the RX, which may not be a good thing, especially if the volts and amps are not the same as the stock external BEC.
Door sequencers can be had from Freewing or FMS. They should work the same. It's too bad that HobbyKing's customer service is so bad. They've never really been that good in the first place. As for the wiring mess, don't let how it looks make you think the plane is unreliable. I've got Freewing planes and FMS planes that have similar rat's nests and they operate just fine. I haven't read much about this plane's crash record. All I can tell you is that mine has been very good from the beginning. I broke the little arm on the nose gear door on the grass but a little epoxy and it's been good ever since. Other than, I've had zero problems with mine. As for one of the gears failing, it's basically has only 2 retracts. One servo controls all the main wheels and another controls the nose gear. Worst case scenario, I believe this plane would be able to belly land quite well since the bottom is fairly flat and big in area.