Because of inverted compass, as described in another thread, my 3DR + brand new APM2 went down, and it took 5 days to get a SCUBA diver to get it (I sold my SCUBA equipment a while year ago)
I memorised the position where it went down by observing the background and the fence, so I could guide the diver from land to the right spot.
-submerged in fresh water.
-gently dried off with towel.
-GPS shield and metal shield over switchmode 5v regulator desoldered.
-slowly baked with increasing temperature to 70degree for 2 hrs.
-Then everything got 10 minutes in ultrasonic bath filled with acetone.
-baked slowly up to 70 degrees.
- all gold plated pin headers got deposits wiped off on each side, all look good.
My APM2 is now rusted will never be reliable: (before ultrasonic bath.)
1 prop broken on impact.
prop adapters and not shiny anymore - interesting how they corroded.
Motors; ball bearing certainly die soon. Otherwise, I guess the wet part of the cables can be cut away, and they can work for testing - not reliable ?
Power distribution board; very corroded, can be made usable.
DEAN connectors, certainly not gold covered, destroyed. Some female DEAn connectors most damaged.
EC3 battery connector; connector surfaces good as new (gold plated), some corrosion on the soldered end.
-3A 5V Switch mode regulator ; (with the metal cover off) - little corrosion, works fine.
-Bluetooth module - works fine
-ESC's (4x Turnigy plush) - all burned, logic starts, but FETS are burned.
-Graupner HoTT GR16 , RX/TX, works fine, very little corrosion, lost one antenna, will be reattached, and then tasted for range. - looks very good.
-Micro SD Card, never worked, (did not got any reply on this from support) it looks very good.
-APM2 looks awful - -The small plastic connectors are not gold plated, and are destroyed.
- I will now bake the working parts again for moisture - then cover in acrylic
Will test APM2 - to see it it can be used for unimportant testing - as it will never be a fully reliable APM again.
Still hoping that DIY will warn all users of this dangerous Compass reversal problem.
They did not bother to do so when I mailed them right after analysing the crash - nor did I ever got any resonse to the uSD card that never appears as inserted.