IT'S ALIVE!!!!!
First test is promising. I don't want to get over-excited... but am! Think the mod worked... tomorrow I will test it extensively but made a flight today to 230 metres (755 ft). It does not sound much, but it is a big difference from what I was getting before the MOD.
UPDATE: Flown line of sight over the sea at 50 m height (165 ft) to a distance of 498 m (1634 ft) before it lost signal and started auto rh. Not the best range ever, but much better than before.
So, first of all, thanks to several people for pointing me in the right direction:
@HappyStandardOwner @agteigarnet @RodPad &
@Stazz. Thank you Alll!
I thought that I could leave here some tips to those who follow. To apply the MOD that was proposed by
@HappyStandardOwner with the tweak by
@agteigarnet you will need to make some preparation, and have basic knowledge in soldering. However, it is not impossible to the humble mortals like me. Here are my tips:
1. Read the posts before this one, especially those by
@HappyStandardOwner &
@agteigarnet
2. Get a decent workshop; you will need a few tools and material:
a. Soldering iron and good quality solder
b. A short length of thin insulated electrical wire. I used a wire that was 0.7 mm (0.03'') in diameter (measured with a calliper)
View attachment 100837
c. Fixed magnifying lens. Optional, but it will help a lot!
View attachment 100838
View attachment 100839
d. Tweezers
e. Scalpel, X-acto or other very sharp tool to remove the malfunctioning S20 chip
f. Good lighting
These are VERY small parts, and a challenging soldering. Just to give an idea, here is my finger close to the working area
View attachment 100840
3. Make sure your soldering iron has a small enough tip. If not, you can improvise one using a copper wire twisted around the iron tip; if necessary you can further sharpen the tip with a file.
View attachment 100836
4. DO NOT attempt to make the MOD without training. I spent one afternoon practising with an old electronic board and the next morning I trained a little more before attempting the MOD. This will show you what can go wrong and give some muscle memory.
5. Cut the wire to the desired length (less than 1 cm; 0.4''), expose a small amount of the metal wiring (~1 mm; 0.04'') on both sides and apply solder to the ends, leaving a very small (almost undetectable) drop of solder.
6. Crack the drone open (if you never did it, watch some videos before you do it). REMOVE BATTERY! Locate the metal rectangle with the little holes and gently pop it open with a small screwdriver.
7. Remove the damaged chip (refer to the posts by
@HappyStandardOwner &
@agteigarnet). For me, this was one of the trickiest parts. Perhaps I should have tried to de-solder it, but I was assured by a friend it should pop out easily with the stroke of an X-acto blade. It did not. I finally used a scalpel blade and it took me a few trials before it popped out. I have no way of saying which is the best method to do this, HOWEVER, this seems to be an essential step to make the MOD work properly.
8. With a COLD soldering iron, practice your movements over and over again.
9. When you are confident you nailed it, plug in the soldering iron and do the soldering: with the tweezers hold one of the ends of the wire to the end of the SMD capacitor close to the chip and touch it with the soldering iron for just one second, max. It should stick there really fast. If not, let everything cool, review the solder on the wire and try again. Then do the same with the other end of the wire to only one of the antenna capacitors (again, refer to
@agteigarnet post on this).
Below an example of the finished job
View attachment 100842
10. The choice of antenna capacitor seems to be free. Other people here made it to the top one; I made it to the top one and then changed to the lower one, and it seems to be working.
Below an example of the connection to the top capacitor (top image) and then to the bottom capacitor (bottom image). Notice that in these pics the chip was still attached to the board. It needs to be removed to ensure the mod works, as in the image above.
View attachment 100841
11.Finally, I suggest isolating the area from moisture in some way. I used a professional coating spray (nano protect) but I believe a drop of hot glue would do the trick.
REMEMBER: this is a delicate and dangerous MOD. If you choose to do it, be aware that you can damage the drone to a point of no repair. Be warned: some people have attempted this and bricked the drone. If you have a choice, send it to servicing by DJI. If you do not have a choice, make sure you understand all the steps, practice, practice, practice, and GOOD LUCK! As anyone in here, I cannot take any responsibility for the outcome if this MOD...
Just for fun, here are plots of the signal before and after the MOD (from AirData)
Before
View attachment 100848
After
View attachment 100849
Wish everyone well and happy flights!
