Beefing Up The Spektrum AR6200

The following article is nothing more than a project report. I take no responsibility for how others may use this information.
There has been a decent amount of talk on the forums about the Spektrum AR6200 receivers failing when used on bigger helis. I have been using an AR6200 in my Protos for almost a year now with no problems and so when I got my new TRex 550e, I grabbed another. When I told others about my choice of rx, a few warned of problems and linked to a few threads on the issue. It would seem that the AR6200 uses a very small circuit trace as the power buss for the servos and it can fail when using full size digital servos. Intrigued, I took the AR6200 out of my 550e and opened it up. Sure enough they are using a single, very small trace to handle all the current needed by the servos, a current that can be in excess of 10A for short periods. So I thought why beef it up? And so I did and here is what I did.

The subject

Opening Up The AR6200
I found this to be the hardest part of the whole project. Even being careful, I snapped off one of the little catches. I am pretty sure there is no perfect tool for this job. I used a little flat blade on my pocket knife and took my time. Once it is open, here is what I found.

Snapped off a catch …

Taking the board out and flipping it over shows the trace that started me on this project.

That little trace has to handle all the current the servos use!

I have seen several photos of that small trace burned out. Knowing the pin-out for servos, I knew the left row of pins are the signal connections, the middle row is the V+ connection and the right row is the ground connection. My goal was to beef up both the V+ and ground rows.

Time To Get The Soldering Iron Out
Because I was working on factory made board, I re-remelted each solder joint I plan to work on and added a little of my own solder. This removes any oxidation or coverings on the solder joints and makes them much easier to deal with.

Melt each joint and add in a tiny bit of new solder to each.

Next up I prepared the wire used to beef up the bus. I used standard solid phone line wire. This is the same type of wire that comes in cat5 wire used for networking. It is 22 AWG I think. The wire is about the same size as the pins on the other side of the rx.

I started by stripping off the insulation on a few inches of the wire and then I tinned an inch or so of it.

Once I got the wire well tinned, I cleaned the tip of the soldering iron well and added a tiny bit of new solder. I placed the tinned wire exactly where I wanted it and melted the solder to connect it to the the first pin. I wasn’t too worried about getting it perfect right away, I just wanted the wire to hold in place. Next I lightly soldered the wire to the last pin. Once I was happy with the position of the wire, I then went to the middle pin and worked my way out. I made sure not to hold the iron on the board too long, as I didn’t want to hurt the board. My soldering philosophy is “get in and get out quick”.

Once I had the middle row of pins is done to my liking, I clipped the end off the wire and got ready to do the other row. Below is the end result.

Testing The Receiver
Once the mod was done, I double checked all the solder joints. I used a camera to get a nice clear macro shot of the end result and studied it for a minute on my computer. Everything looked good and solid, and most importantly clean. Next up was a range test. I used an extra bec and old servo. All checked out fine, but I was still careful on my first flight.

In Conclusion
Was this mod worth the effort? The risk? Would I have been better off to just use the better AR7000 receiver instead? These are all questions that I asked myself but being a tinkerer, and I knew I could pull it off with a problem. In the end if this mod allows me to run the AR6200 receiver in my larger models without the fear of toasting a trace and causing a crash, then it was worth it.

All information has been referenced from the Tjinguytech.