Interesting conclusion on disconnects from app and rc

mnoutdoors · Jan 8, 2018

Update, sent MP in to be repaired it turns out it was the rc controller board on the MP was bad, it was covered under normal warranty no refresh used. They received the MP last Friday, I got the email today, (so 2 days )it’s being repaired Today, pretty good turn around time, as long as it works as it should when I get it back I’ll be pleased.

Mossiback · Jan 8, 2018

mnoutdoors said:
Update, sent MP in to be repaired it turns out it was the rc controller board on the MP was bad, it was covered under normal warranty no refresh used. They received the MP last Friday, I got the email today, (so 2 days )it’s being repaired Today, pretty good turn around time, as long as it works as it should when I get it back I’ll be pleased.

I am glad your problem has been solved. Where did you send it for repair?

mnoutdoors · Jan 8, 2018

They had me send it to Texas

mnoutdoors · Jan 11, 2018

Further update, Mavic AC was returned after about 2 weeks, they installed a new RC control board in AC and supplied a new RC also. so I bound RC to AC and just sat it on a table to test.............and same exact thing
4 minutes 13-15 seconds RC disconnects app says weak signal readjust antenna and immediately disconnects
For about 2 seconds and comes back online and in 4minutes 13-15 seconds it does it all over again. So I called DJI talked they said install new FW which I did I really had my doubts I even told the Tech I would bet a $100
It would not change a thing. It didn’t............. so now I have a new case number and back it goes they think it’s the mother board now........ at least my other Mavic is working fine

I did ask if they could test it this time before sending it back .........

mnoutdoors · Jan 18, 2018

Ok, I received a email the MP is getting a new core board, I hope this does it.

cfoxtrot · Jan 18, 2018

mnoutdoors said:
Ok, I received a email the MP is getting a new core board, I hope this does it.

Good luck!!!

SouthernComfort · Jan 18, 2018

This is quite interesting to follow! We have some very smart sumbitches on this forum. Present company excluded of course.

mnoutdoors · Jan 25, 2018

Update, MP appears to be cured they installed a new control board........ hurray

grinder · Jan 25, 2018

It does make you wonder if the repairer fully read the problem you are having and actually tested it for 4 minutes 13 sec or the more likely situation is they replace the part, 30 second test and have boxed it up in less than 4 min. Would be cheaper if they slowed down and fully addressed the problem. Unfortunately their productivity is measured by jobs completed rather than successfully completed.

mnoutdoors said:
Further update, Mavic AC was returned after about 2 weeks, they installed a new RC control board in AC and supplied a new RC also. so I bound RC to AC and just sat it on a table to test.............and same exact thing
4 minutes 13-15 seconds RC disconnects app says weak signal readjust antenna and immediately disconnects
For about 2 seconds and comes back online and in 4minutes 13-15 seconds it does it all over again. So I called DJI talked they said install new FW which I did I really had my doubts I even told the Tech I would bet a $100
It would not change a thing. It didn’t............. so now I have a new case number and back it goes they think it’s the mother board now........ at least my other Mavic is working fine I did ask if they could test it this time before sending it back .........

chazz · Feb 20, 2018

Keule said:
@mnoutdoors Interesting find.
Being in IT for a long time, i'm always looking for bugs, flaws or other glitches in software code.

So, t seems there could be a buffer overrun somewhere in the code (either on the RC or AC).
Why? Covert your finding into seconds will give you 254 seconds. [(4 min * 60) + 14 seconds)]
Thinking in Bytes, then there is 1 Byte = 8 bit = 256 decimal. (2^8)

Given the fact that your measurements are precise, whenever an internal counter (for whatever reason) or buffer, an array reaches 254 or even 255 (more likely), the firmware initiates a 'mini' reboot of a module, leading to the disconnects.
Counters, variables are reset, and 'redo from start' for another period of 254 seconds.

Note: the above is only an assumption! So don't take it as granted! But i am on it.

What firmware did you tried?

This is interesting to me. I don't know if you ever looked in the parameters but there are some parameters called "map" and they're numerical 1 to 29 (map_1 to map_29) and they all have a value of 255. Is it possible they add these up for some different parameters for use in time settings?. Like you said 255 seconds = (4min 15 sec). Lets say they want something to happen after 1275 seconds would they use a value of 5 (255 x 5)?