Was given this 2 years back.  Never been able to make it operate

Charged the batteries
Fitted propellors as instructed
Downloaded the App to iPhone
Attached phone to controller
Switched it on
Switched on aircraft
Light to left on controller turned green
App said "Calibrate".  Turned drone 360deg horizontal, then 360deg vertical
App still said Turn vertical, so did this another 3 times
Two lights on drone flashing red, two steady green
Took it outside, 5m from controller
Can see pic from device camera
Selected "Take off" on app.  Nothing happened
Looked at Aircraft Status - next to Compass it says [Calibrate].  Did this another 5 times, but Calibrate won't go away
Downloaded manual, but there is no troubleshooting guide
Took it to dealer, he takes one look and says it is out of guarantee and is disinterested
Really have no idea how to proceed
Thank you

You're in the right place for beginner info! We were all beginners at one time, myself a couple of years ago at 80!!

Advanced or Pro (not that it makes a lot of difference).
Sounds as if everything is on and linked - green lights.What position is the Flight Mode Switch on the controler in? Should be on "P".
Check on the screen that you have satellites - top left.
Did you manually start the motors up? No? Pull both left and right sticks downwards and inwards? The motors should start up, a burst of power, and then idle, let go the sticks. You are ready to take off.
Check you are clear to do so and now manually take off, using the L/H control stick on the remote controller, push it very slowly forwards. The motors should increase and the drone lift off.The big advantage of being in "P" mode is that let go the sticks and the drone should just hover where it is!

Thanks, the first YouTube clip was very informative

When both sticks are pulled downwards and inwards, all that happens is that the Status screen reappears and covers the camera image and the two green lights flash red
The Flight Mode Switch is on "P"
The Satellite indicator shows 9, sometimes 11

I thought as a beginner to use the (^) symbol on the left and use the Slide to Take Off >>.  This just brings up the status screen and the green lights flash red

Later today:

Just come back from 2 hours on a farm, at least 1km from any Wi-Fi signals

As soon as I try a Take-Off, a message "Calibrating IMU" appears.  I tried it on an off for 2 hours, seeing the green lights turn to red when I rotated the sticks as above

Is there a procedure to calibrating the IMU?  I cannot see any reference to it in the manual

In the Status screen, the IMU changes from Normal to Error frequently

Welcome chrisc !! Hope it helps ;)

I would review these tutorials, maybe you skip some step Good luck

JetSam Posted at 1-24 02:30
I would review these tutorials, maybe you skip some step  Good luck

I think one problem I can see, there is no wi-fi from the device

It was like this from day one, Jan 2019.  Maybe it is switched off somewhere?

Very basic but have you selected the correct drone from the GO App start-up screen?

chrisc@14 Posted at 1-24 05:38
I think one problem I can see, there is no wi-fi from the device

It was like this from day one, Jan 2019.  Maybe it is switched off somewhere?

Can you confirm exactly what model Phantom 3 you have?  Pro, Advanced, Standard...  Start with the colour of the stripes on the arms and what is on the front nameplate if you don't know how to tell.

It is a Phantom 3 Advanced
This is shown on the initial screen and on the silver label on the device

We both went through this for about 2-3 weeks when I was given the device just 2 years ago.  Then the person who gave it to me visited the country again and came around in December and we tried to get it going
Both batteries were charged and also the controller
We went through the procedure as explained in the very brief documentation, but it would not start
Yesterday I did this IMU calibration as described in the YouTube clip.  It took about 10 mins
Taking it outside again, as soon as the levers are rotated, or Take off is selected, the two lights that are green flash red

There are three different Red Flashing indications, you need to decide which one it is. It is quite possibly the batteries if they were not used for two years and allowed to go below their critical voltage. Even though you have apparently "charged" them, they may well be duff!Look up the battery section of the manual and it gives you various tests you can do to establish the usability of the battery.

There are 2 green lights and 2 yellow ones

When the "Start" command is given, the two greens turn to red and flash

During the time the device was not used, I took out the two batteries and connected them to the charger.  The battery lights illuminated for about 30 mins or so.  I did this about 6 times during this period

There is a battery graphic on the iPad showing about 95% in each of the 4 cells

The lights on the drone front legs are RED, just to show that that is the front. It is the back lights, where the battery goes, that tell you the condition of the drone, there is one light on each leg.
Not sure what you mean by "There are 2 green lights and 2 yellow ones".  Which are Green and which are Yellow?

Have you got the  USER MANUAL

Look at page 12.

Sorry about all this

I have put it back in the suitcase for another day

That's a bit defeatist chrisc!
In your last post you said "There are 2 green lights and 2 yellow ones".
Are the back lights flashing Green and Yellow alternatively? This just means that the drone is just warming up.
It could take a minute or two to settle down, then what colour are they?

Does this not mean the machine is ready?

Another friend who has his own drone (A Parrot) drone expressed the opinion that there might be something missing or defective

YES! The BACK lights on the drone should now be GREEN and the small, left hand light on the Remote should also be GREEN.

You should;d now be able to pull BOTH control sticks downwards and inwards to start the motors.