Q500 4K No GPS Lock, No GUI

WTFDproject · Jun 2, 2021

There is supposed to be a heavy copper shield inside the Q500, covering the GPS unit to prevent interference from the electronics.
Have you lifted the top shell to ensure the shield is in place?

Foxtrot1 · Jun 2, 2021

WTFDproject said:
There is supposed to be a heavy copper shield inside the Q500, covering the GPS unit to prevent interference from the electronics.
Have you lifted the top shell to ensure the shield is in place?
View attachment 25823

No, I haven't yet. h-elsner made a good suggestion to ground that shield which I will definitely do (if it still does have one) this evening as I'm at work right now. I feel we're really close to what causes this issue. All of your troubleshooting suggestions and those of h-elsner make total sense. After all I've read about ebay sellers, also here and there on used drones, anything is possible. The seller admtted to changing both body shells, so the posibility that this aircraft might not have it's shield in place sounds plausible.

Thank you so much for your assistance and followup. Will post findings as soon as I get back to my bird this evening.

h-elsner · Jun 2, 2021

Another point that comes in my mind is wiring of compass chip. Compass has strong influence on computing of the GPS position data. And the compass is near the camera mounting in the nose of the bird. Some very old Q500 had the compass mounted on landing gear. But usually it should be mounted on a white plastic holder in the nose of the Q500.
- Check if it is tight and correct directed (only one screw holds this thing).
- Avoid compass wiring in parallel with camera wiring. Maybe a small change in how the wires go make a big difference.
- Plug/unplug all connections to reduce resistance made by oxide film on contacts.

br HE

Foxtrot1 · Jun 2, 2021

No dice guys, it has the copper sheet properly placed. So that needs to be scratched out and the wiring is properly isolated also. Wiggled cables and plugs here and there. it has to be in the board. Will have to look at voltage reference points if they are available.

WTFDproject · Jun 2, 2021

We're starting to run out of "home" solutions. The next suspect would be the small circuit board in the belly of the Q500 associated with the pigtail cable. It may have some sort of problem. If so, the problem could be bypassed by re-attaching the three black wires and using the normal hot-shoe circuit board. Your photos indicate the "pwm" solder pad and trace were ripped out. That one you will have to solder to the back of the pigtail connector on the gimbal board. It goes to the pin on "drone left", closest to the area of the other two wires.

Foxtrot1 · Jun 3, 2021

WTFDproject said:
We're starting to run out of "home" solutions. The next suspect would be the small circuit board in the belly of the Q500 associated with the pigtail cable. It may have some sort of problem. If so, the problem could be bypassed by re-attaching the three black wires and using the normal hot-shoe circuit board. Your photos indicate the "pwm" solder pad and trace were ripped out. That one you will have to solder to the back of the pigtail connector on the gimbal board. It goes to the pin on "drone left", closest to the area of the other two wires.

It seems it's not an isolated problem, there are others experiencing this. The video below details the same exact issue, that removing the camera and gimbal, the Q500 will collect enough sats to get a proper lock. Ironically the video itself has more thumbs down that up.

Will disassemble again tonight and start collecting voltage readings.

h-elsner · Jun 3, 2021

Would you like to show us flight logs with and without camera? In the video above he had not GPS lock and the the cam is powered down (not connected). Do you have the same? Means No GPS when camera is mounted without power? You must remove the cam away to get GPS?

br HE

Foxtrot1 · Jun 3, 2021

In the video, actually he does have power to the camera as seen on the controller screen, the camera seems to be pointing downward showing grass and the GPS icon is showing "Acquiring" which is exactly what my Q500 is doing.

Yes, when the camera is removed (Q500 turned OFF, remove gimbal/camera, then turn Q500 on again), I get GPS "Ready" or locked. When the camera is attached (by the ribbon), the camera actually works fine, I can control camera movement like nothing is going on, but I will not lock into GPS and fly unless I would manually turn the GPS off.

I have NOT flown the Q500 yet since I received it as-is from the ebay seller a couple of frustrating days ago in fear of losing it. I would prefer to have GPS with a new bird until I feel comfortable flying it.

Foxtrot1 · Jun 3, 2021

Foxtrot1 said:
In the video, actually he does have power to the camera as seen on the controller screen, the camera seems to be pointing downward showing grass and the GPS icon is showing "Acquiring" which is exactly what my Q500 is doing.

Yes, when the camera is removed (Q500 turned OFF, remove gimbal/camera, then turn Q500 on again), I get GPS "Ready" or locked. When the camera is attached (by the ribbon), the camera actually works fine, I can control camera movement like nothing is going on, but I will not lock into GPS and fly unless I would manually turn the GPS off.

I have NOT flown the Q500 yet since I received it as-is from the ebay seller a couple of frustrating days ago in fear of losing it. I would prefer to have GPS with a new bird until I feel comfortable flying it.

Wait...I just realized what you are most probably refering to regarding powered down, meaning it is working but not leveling out as in ready to record mode, maybe?

If my "new" understanding is correct, then my Q500 does power up and connect properly to the camera and it does level out perfecly. I hope this is the answer you were expecting.

Foxtrot1 · Jun 5, 2021

How about the GPS module itself.

- Wouldn't it be part of the equation on this issue? It does have a battery.
- What if...the battery is low, wouldn't that impact in some way the module's operational capacity?
- It is plugged into the main board so there is some obvious communication happening.

I have seen how complex the on-board electronics is on these birds and because the GPS is working to some extent, (the battery drain of this module must be very, very low) as the GPS module has to be registered on the main board's processing unit as a powered accessory and a voltage below the necessary level might not be providing the necessary signal output (?). These are just things I'm bouncing off the wall here, don't take them as an informed point of view : )

Is there a trouble-shooting flowchart on this board?

I'm taking it all apart again tonight to take a really good look at it all and test what can be tested without a service manual, just by common sense.

DoomMeister · Jun 5, 2021

The battery is there to retain the ephemeris data when power is removed from the aircraft. If the battery were the issue you would have the acquiring issue with the camera removed. There has to be an issue with the camera pulling voltage levels down or causing interference with the GPS.

Foxtrot1 · Jun 5, 2021

I'll be scratching that one out too then. Back to square one.

Foxtrot1 · Jun 13, 2021

Ok, I have an update.

I was finally able to get the Q500 working with the GUI which brings one question:

- Does the GUI identify between the basic Q500 and Q500 4k versions and state it as such? Checking the enclosed image on identification, it reads Q500.

All other sujects appear to work as intended and check out ok with the green checkmark, same with the rotor motors, they all pass.

WTFDproject · Jun 13, 2021

There is no difference between a Q500 and Q5004K related to the GUI, other than the gimbal calibration. The one on the GUI will only work with the older CGo2 camera. There is none for the CGo3.

Foxtrot1 · Jun 13, 2021

Woah...when you say "the one on the GUI will only work wth the older CGO2"...does this mean the one I have hooked to the GUI?

WTFDproject · Jun 13, 2021

Foxtrot1 said:
Woah...when you say "the one on the GUI will only work wth the older CGO2"...does this mean the one I have hooked to the GUI?

Not sure what you have hooked to the GUI. All I meant to say was the "Calibrate Camera Gimbal" button was there before the 4K camera was released, and only works with the CGo2 camera that came on the previous Q500 models. It does not work to calibrate the CGo3 camera that came on the Q500 4K. But everything else on the GUI works for all of the Q500 series drones.

Foxtrot1 · Jun 13, 2021

Thanks for the clarification.

How can I define the version of Q500 that I have? This is actually what I'm getting at. I just can't seem to find anything wrong on this aircraft and am thinking since I can't get GPS to lock with the camera hooked on but can manage to control the camera, and on the other hand, I do get a GPS lock without it, maybe I have the prior model version that uses the CGO2 (this is my uneducated reasoning here).

Please recall that the seller changed the upper and bottom body shells and away went the factory model tag and serial number, hence there's nothing user-obvious to reference it and if in fact I have the Q500 4k that I paid for.

h-elsner · Jun 13, 2021

The Q500 is a Q500. There is difference at the drone itself. It can carry a CGO2, CGO2+ or a CGO3 or a gimbal for GoPro camera + MK58 as WiFi video transmitter. CGO2/CGO3 have the WiFi video transmitter build-in.

Your problem with GPS lock seems to be caused by interferrences between camera and Compass or GPS module. I do more refer to compass chip in this case because it is near to the camera.
Check following:
- Are the wires to compass correctly drilled? This needs be the case to avoid interferences.
- Are the plugs all tight? Disconnect/connect both sides of the wiring.
- Is the compass orientation correct and is it tight?
- Move wiring of camera and compass away from each other as good as it is possible.
- Is compass calibration successful with camera powered on?

For debugging it would be good to exchange the possible sources of the problem to isolate it:
- Camera
- GPS module
- Compass inclusive wiring.

Do you have the possibilty to test with another CGO3 camera (one from a friend or so)? This would be my first try...
And again the question for FlightLogs with/without camera.

br HE

WTFDproject · Jun 13, 2021

Foxtrot1 said:
Thanks for the clarification.

How can I define the version of Q500 that I have? .....
.... the seller changed the upper and bottom body shells and away went the factory model tag and serial number, hence there's nothing user-obvious to reference it and if in fact I have the Q500 4k that I paid for.

Your GPS issue is not a model compatibility issue. All versions of the Q500 are compatible with all cameras designed for the series.

To address the issue of true 4K or not, the main difference is the camera mount on the drone. The 4K camera mount has contacts in the mount itself, allowing you to mount and dismount the CGo3 camera without using the pigtail cable and the connector located on the drones belly just behind the camera mount. If your drone has the contacts (hotshoe mount), it is a legitimate Q500 4K.
The 4K also has the belly connector to use if needed for other camera models.

Foxtrot1 · Jun 13, 2021

h-elsner said:
The Q500 is a Q500. There is difference at the drone itself. It can carry a CGO2, CGO2+ or a CGO3 or a gimbal for GoPro camera + MK58 as WiFi video transmitter. CGO2/CGO3 have the WiFi video transmitter build-in.

Your problem with GPS lock seems to be caused by interferrences between camera and Compass or GPS module. I do more refer to compass chip in this case because it is near to the camera.
Check following:
- Are the wires to compass correctly drilled? This needs be the case to avoid interferences.
- Are the plugs all tight? Disconnect/connect both sides of the wiring.
- Is the compass orientation correct and is it tight?
- Move wiring of camera and compass away from each other as good as it is possible.
- Is compass calibration successful with camera powered on?

For debugging it would be good to exchange the possible sources of the problem to isolate it:
- Camera
- GPS module
- Compass inclusive wiring.

Do you have the possibilty to test with another CGO3 camera (one from a friend or so)? This would be my first try...
And again the question for FlightLogs with/without camera.

br HE

Thanks h-elsner,

I really have to disassemble it and work my way through, you may very well be correct with your reference to interference. I should be receiving a new GPS module in the next few days, so I will be able to compare, also the cable that connects the gimbal to the belly of the Q500 is being replaced. I will try to get another compass on ebay. The camera will be the last thing on my list. I am trying learn on what might be the cause before I render myself to just swap the camera.