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Repair Help - Inspire 1 still powering up after 24hr water immersion

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I recently crash landed my Inspire 1v2 X5r into a fresh water lake where it remained submerged for 24 hours until I was able to recover it. After thorough cleaning and drying of the I1 and the x5r, I was amazed to see that the x5r (tested on an Osmo) was still completely functional ( including the SSD and footage). However the I1 did not fair so well, even though it still powered up it did not complete the start up sequence - one motor started to smoke and the RC would not connect with the Inspire (the motor felt pretty stiff before power up anyway so smoking was no surprise). So I’m wondering if the my I1 is repairable and in what order to test and replace components? Is it best to swap out the motor and ESC first to see if this would allow the start up sequence to progress allow a connection to the RC? Or does the lack of RC/I1 connection indicate that I’d be better swapping out the I1 flight controller/ motherboard first? Any advice gratefully received.
 
Well, honestly, your bird needs:

- All 4 motors and ESC to be replaced (none of the motor internals are stainless steel, thus all the bearings and other parts are corroded)
- The lightbridge module needs to be replaced (it has a ton of connections and they are all compromised, and it has no potting to allow for water submersion so it will have problems)
- The main power board might be OK, but all the small white connectors need to be unplugged, cleaned and plugged back in to make sure there is no corrosion issues in the future)
- The center landing gear lift-screw module needs to be removed, torn down and cleaned and lubed. Honestly, again, it is not stainless so the bearing and motor WILL have issues in the future, so it is best to replace this assembly as a whole as well.
- The remainder of all the white connectors everywhere need to be disconnected, cleaned and reinstalled. This includes all modules, lights, sensors, etc.
- The heavy-duty power wiring needs to be disconnected and reconnected at every connector (you will do the ones at the ends of the wires near the motor/ESC modules when replacing those and need to do the ones at the main power board).

So, a complete tear down of everything is required to make it reliable.

If you do not do all of the above, you run the risk of the aircraft having a critical failure while in flight and the almost certainty of it falling out of the air while in flight and hurting someone and damaging property.

In other words it is NOT air worthy without all the above. It would be irresponsible to put it in the air.

No different than a flood damaged car.

If it was in the water for less than a five minutes it would be no different. The only thing that would have made it worse would be if it went into salt water. Even then a few minutes is the same as your 24 hours in fresh water. Submersion in salt water for 24 hours and NOTHING outside of the plastics and carbon fiber parts is useable.
 
Salt water would definitely short things. That said, distilled water could be used to clean the salt. The problem is being on when it goes into the into the water, causing shorts and other damage. When things like this happen, it's best to disassemble everything, use an air compressor everywhere to get most of the water out right away to minimize rust and corrosion. The rice thing isn't a bad idea it's just an alternative to a more efficient commercially available desiccant. Best to let things dry after that for about a week. Patience is key. Being anxious to fire it up to see if it works will inevitably cause more damage.

But as was previously mentioned, definitely irresponsible to put it in the air with out through air worthiness testing in a safe and secure environment to determine the extent of the damage and assess what needs to be replaced. Ideally you would have another identical working drone to test components on but realistically this isn't an option for most of us.

Like a flood damaged car, it might be better to cut your losses, salvage what you can for spare parts, and just get a used replacement from eBay. There are quite a few Inspire 1's on eBay and many without camera's that people are trying to unload that are fairly priced. I have to believe getting a used replacement wouldn't be any more expensive than getting replacement parts.
 
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I had an S900 that ended up in a freshwater creek submerged for about 8 feet for 10 minutes until my frantic diving skills retrieved it. (A red-tailed hawk did not agree that the FAA controls the airspace.). It took about 30 minutes to get home, where I immediately started disassembling everything and liberally using compressed air everywhere. After tracking every bit of liquid I could find, I spread all the parts that were not carbon fiber and simple plastic (they are immune to the simple rinsing that the creek provided) on small towels in the kitchen electric oven and left them at 115 degrees (F) for 24 hours. Tossing the 22,500 mAh battery nearly brought me to tears. Luckily, the GH4 and gimbal weren't attached because I was testing the newly upgraded arms and motors.

After another two days of room temp drying and in the sun on the patio, I re-lubed all the bearings, spun everything and re-assembled. I put lead weights on the landing gear to hold it down and finally powered back up. I ran it through all the tests I could and then took off and let it hover (tethered) in the back yard at 4 feet for a couple batteries. To my surprise, the A2 controller, GPS and all the other components survived.

Corrosion with fresh water contact is not a problem for short time frames. The battery contacts directly short out and quickly eliminate any power to the unit. The biggest mistake is impatiently trying to apply power without COMPLETELY DRYING EVERYTHING. All components will handle the 115-120 degree oven temps. I've flown in those temps in the desert!

I cautiously tested for several more simple flights before attaching the gimbal/GH4 and returning it to normal service. Still pull it out ant fly it occasionally to keep the big batteries working.
 
Back in the day I had an entire vase of water fall into my horizontal computer tower. The motherboard was literally submerged in water, but the power was off. Like JimBinDallas, I completely cleaned and dried everything with compressed air and then I let it dry over a period of 2 days. 2 days later I was able to re-install and fire up the motherboard. Success! I continued to use that motherboard for about 2 years after that.

As long as electronic parts have not had power applied to them, they CAN be dried and restored.

D
 
Back in the day I had an entire vase of water fall into my horizontal computer tower. The motherboard was literally submerged in water, but the power was off. Like JimBinDallas, I completely cleaned and dried everything with compressed air and then I let it dry over a period of 2 days. 2 days later I was able to re-install and fire up the motherboard. Success! I continued to use that motherboard for about 2 years after that.

As long as electronic parts have not had power applied to them, they CAN be dried and restored.

D
For stuff like motherboards and pure electronics I completely agree. With power off you run the real possibility of being able to dry it out and it works just fine.

I was referring to speed controllers and power circuits (like the main power board and the ESCs for the motors) along with things with bearings of any sort (motors, landing gear worm gear motor and lower bearing, fans in the Lightbridge module, etc) that can be compromised with corrosion. Honestly, I am not sure the antennas in the legs are impervious to corrosion in regards to being properly functioning antennas. Does corrosion change the attenuation?

It is well known that most bearings used in a lot of stuff today are low-cost bearings sourced from Chinese companies with minimal specs, which means they are most certainly not stainless steel construction and with minimal grease. Thus submerging any of them now leaves them in a highly questionable state. The longer the submersion, the more likely they are compromised.

The big issue with the power board and ESCs is that current WAS flowing through them when it crashed. No idea what was compromised in the "shorting out" that happened during submersion while having powered applied. A weakened ESC is unreliable for flight as it can fail at any time. Thus the reason why I stated the main power board and all the ESCs/motors need to replaced at a bare minimum.
 
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You could sell the mechanical parts: arms, frame, propellers and junk the electronics. Buy a used I1 and you'd almost be back where you started. All the parts you should buy are more than just buying a flying airframe.
 

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