Core board power supply?

[ChipZ_601]

Hello fellow Mav owners. I crashed my Mav early August in about 20' of water. I looked extensively with sonar but no luck. I finally found it using another Mav with the Litchi app installed and using the gps coordinates from the flight records. Dove down and got it on the first dive. I soaked it in 91% isopropyl for a few hours and let it dry for a while. When I powered it up there was two arc's from below and a little smoke. Since then I have no power on the lower board (core board a). I'm looking for help figuring out how this board receives power. I think it comes from the upper board via a ribbon cable located on the upper board top right. But I'm not sure. Of coarse I looked all over for a diagram or schematic on the web but no go. Any help would be greatly appreciated!

 

[Darth SHO]

View media item 2294Maybe this will help:
Dji Mavic Pro Parts Diagram Beautiful Preview | Wire Diagram

 

[ChipZ_601]

View media item 2294Maybe this will help:
Dji Mavic Pro Parts Diagram Beautiful Preview | Wire Diagram

Thanks. But this isn’t for a Mavic. Nase 32 board.

 

[Tesadorn]

Hello fellow Mav owners. I crashed my Mav early August in about 20' of water. I looked extensively with sonar but no luck. I finally found it using another Mav with the Litchi app installed and using the gps coordinates from the flight records. Dove down and got it on the first dive. I soaked it in 91% isopropyl for a few hours and let it dry for a while. When I powered it up there was two arc's from below and a little smoke. Since then I have no power on the lower board (core board a). I'm looking for help figuring out how this board receives power. I think it comes from the upper board via a ribbon cable located on the upper board top right. But I'm not sure. Of coarse I looked all over for a diagram or schematic on the web but no go. Any help would be greatly appreciated! View attachment 47079View attachment 47080

Can you post links to the schematics? I will try to help.. This interests me as I just picked up a damaged Mavic myself to repair

 

[Tesadorn]

Can you post links to the schematics? I will try to help.. This interests me as I just picked up a damaged Mavic myself to repair

Ahh sorry! misread... Thought you had FOUND them!
I will recieve the crashed drone today... I'll poke around for you if possible. Can you post a pic of your core board? front and back?

 

[Red Baron]

If it arced when you fired it up the mother boards are toast

 

[ChipZ_601]

Yea, not so sure about the boards all being fried. I’ve had smoke come out of other boards and had them still work. These new mosfets can take a beating! I’m pretty sure the ribbon cable from upper board had insulation that was exposed and it touched something. Also, the screws that hold the board might actually be for grounding. I didn’t have them installed as I wanted to see if it was actually going to fire up. Anyone know if the board uses mounting screws to pass current?
I ordered new ribbons that should be here today. If this fixes it I will let you all know if it works. Fingers crossed.

 

[Tesadorn]

Few things...
1. The screws do NOT carry voltage.
2. The screws do not form a grounding plane as the entire body is plastic.
3. If you have seen and smelled electrical burning chances are something is damaged..
4. Post pics so we can help!


I spent my time last night testing the damaged drone and re-flashing it to .700
It does look at first glance that the core board gets power from the one ribbon connection. I will know for sure when I swap frames in a few days.. (waiting for a few parts and silicon).

 

[ChipZ_601]

Thanks! I would post pics but they don’t look any different then any image you would find on the internet.

 

[Tesadorn]

Without pics it will be VERY difficult to help troubleshoot... I disagree about them being the same!

 

[ChipZ_601]

@Tesadorn, my question was asking about the power to the main board and if the screws actually do anything. Being some of the screws that hold the two boards to the frame have gold/copper exposed. They definitely are grounds as I have used a meter to check for power and they all act as ground. As to the frame being made from plastic, I wouldn't put it past DJI to have used some filament inside to conduct so the boards could be grounded evenly. Preventing a spike.

 

[Tesadorn]

ok....

 

[Tesadorn]

So... did you get it in the Air??

 

[Kilrah]

Power is supplied through the one flex cable that goes between the 2 boards.

 

[Darth SHO]

Thanks. But this isn’t for a Mavic. Nase 32 board.

Sorry! I'm not that familiar with the Mavic circuitry. I found that with a quick sesrch. That site has a lot of wiring diagrams....

 

[ChipZ_601]

Update: New ribbon cable smoked just like the last one. There is a short on the core board. Esc board is good. It turns on, motors spin on turn on, and camera gimbal goes through its normal check. I think a new core board would fix it. They cost $195 on eBay and Amazon. If anyone has a used one that works and they want to sell let me know.

 

[Tesadorn]

Buy a crashed unit.. you will also get spares...