I'm stumped

[Mattx222]

Hey guys. I had a hard crash with the throttle on today and now when I plug the battery in and wait for it to connect and the blue light to come on and the blue light flashes really fast and I have no control over it. Sometimes when I connect the battery it come on like it should and I can start spoiling it up then the light goes off and it shuts down. When I crashed the main gear came off and I hit Th to late but there was no throttle inputs done by me And as I was running to where it hit it sounded like the motor was still running full speed then it stopped. Btw it crashed onto a dirt road. So any ideas what is wrong? ....sorry for the novel
Thanks,
Matt

[Derfman]

Originally Posted by Mattx222

Hey guys. I had a hard crash with the throttle on today and now when I plug the battery in and wait for it to connect and the blue light to come on and the blue light flashes really fast and I have no control over it. Sometimes when I connect the battery it come on like it should and I can start spoiling it up then the light goes off and it shuts down. When I crashed the main gear came off and I hit Th to late but there was no throttle inputs done by me And as I was running to where it hit it sounded like the motor was still running full speed then it stopped. Btw it crashed onto a dirt road. So any ideas what is wrong? ....sorry for the novel
Thanks,
Matt

im not sure, but have you tried to re-bind it with another battery?

[koi-fish]

You might have damaged the board, troubleshoot out as much as you can, en PM mega stumbler...........

[Mattx222]

Who's mega stumbler? I really hope the board is okay... There is no obvious damage. And yes I tried with fresh battery's.

[koi-fish]

Spelled his handle wrong....Megastumbler. He's on this forum and can fix many problems on mcpx, msrx boards. Send him a PM...................

[Mattx222]

Sent him a pm, thanks for that guys. Hopefully he can figure it out for me.

[Mega Stumbler]

Crashing on a hard surface is no good for the 3 in 1. There are a few things that may have happened. All of this is assuming you have a good battery, motors, and TX.

The rapid flashing light is the board entering bind mode. It does this because either the RX can not interface with the TX or the MCU can not interface with the RX.

1. The 2.7V voltage converter fell off or has a cracked joint. This happens fairly often in a nasty crash resulting in a board that will not bind. It is the 3 pin part on the front of the board under the negative battery cable. Inspect this under magnification for errors.

2. The crystal is cracked. There is a 12MHz crystal on the bottom center of the front of the board. In a bad crash the crystal under the metal shield can break. This kills the 12MHz reference used by the RX chip to tune to your radio. There is no easy test to check the crystal. If it has physical damage, it is probably bad. If there is no physical damage, you can still not be sure that it is good.

3. The most common cause of failure to bind is broken solder joints on the RX IC. The legs of the RX break away from the board in a nasty crash. These often can not be detected by visual inspection. Removing the epoxy and reflowing the connections is the best method to eliminate the problem. The RX IC is the large black chip on the board's front side bottom right corner.

4. Another common cause is broken solder joints on the MCU. The RX interfaces with the MCU using the pins on the MCU's left hand side. You will have to do the same thing as the RX to repair by removing the epoxy and reflowing the connections. The MCU is the big black chip on the boards back side.

5. The last thing that it may be is a broken IC. It is fairly uncommon that the MCU or RX chip sustains fatal damage but it does happen from time to time. When this happens there is no feasable repair. A new 3 in 1 will be required. I see faulty chips in about 5% of the boards I repair.

There are a few methods for at home repair. If you search the interwebs for toaster oven reflow you will find methods for possibly repairing your board. You may attempt these methods at your own risk. I use a temp controlled hot air rework station for the board repairs. I find it to be much more accurate and safer for the board.

Hope this helps.
Kevin

[Mattx222]

Jesus you know a ton about that. What is reflowing the connections? Thanks for the help.

[Mega Stumbler]

Reflowing is heating the solder to its melting point on both the board and the chip. When solder is melted we often refer that to flowing the solder. Reflowing is just melting it again. Doing this will repair the tiny cracks and cause them to stick together again.

[clough42]

Reflowing is the process of heating part or all of the board to re-melt the solder, repairing cracked solder joints. You can do it one joint at a time with an iron or you can use equipment to heat the whole board.

[everydayflyer]

Goggle is your friend

[Mattx222]

Would that not melt the plastic connectors for the motors and servos? Sorry for all the questions, trying to learn as much as possible.

[Mega Stumbler]

Originally Posted by Mattx222

Would that not melt the plastic connectors for the motors and servos? Sorry for all the questions, trying to learn as much as possible.

The plastic is designed for reflow soldering. If you keep your temps under controll they will do just fine.

[Mattx222]

We have a toaster oven, your saying I can do this just by putting it in there under a set of guidelines I would read on tutorials of course.

[Mega Stumbler]

You can try. Many people have repaired various circuit boards using this method. Its cheaper than a new board and cheaper than sending it to me. But the cost of failure is destroying the board completely.

[Mattx222]

I see. Well I guess I will take a look at it after school today and see if I can figure it out. Hopefully I don't cook my board. Do you know of any toaster oven tutorials other than the random ones on google?

[Mega Stumbler]

If I recall correctly, sparkfun has a good one.