Professional Camera lost communication

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I was shooting a 360 pano when the FPV stopped but I could continue with taking photos. The FPV came back alive for short periods but was lost again. I could still take photos and video but that eventually ceased to function also. The camera control menu on the DJI GO app has gone gray and unresponsive. The shutdown is delayed as the light on the aircraft battery on/off switch continues blinking red for about 13 seconds.

According to what I have read, the camera has stopped communicating. What I am hoping for is that someone with more knowledge than me can recommend to me the best method of repairing it and point me to a clear explanation of how to do that.

Thank you in advance for sharing your knowledge and experience.
 
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The shutdown is delayed as the red light on the battery switch continues blinking for about 13 seconds.
What battery switch? Do you mean the light on the controller? If so, that indicates complete signal loss. The aircraft should RTH within 2 seconds of that, if you have your settings configured correctly. Your description is very vague to help you.
 
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I mean the on/off button on the aircraft battery when turning off the aircraft.
 
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The shutdown is delayed as the light on the aircraft battery on/off switch continues blinking red for about 13 seconds.

According to what I have read, the camera has stopped communicating.
Yes, this happens when FC cannot communicate to the camera.

What I am hoping for is that someone with more knowledge than me can recommend to me the best method of repairing it and point me to a clear explanation of how to do that.
Repairing requires to diagnose the issue first.

Here are possible issues in your case; you need to figure out which one is true:
1.SD-card inserted into ESC Center Board is damaged
2. Gimbal Top Board does not get power from ESC Center Board
3. Gimbal Top Board is damaged, either by software or hardware
4. Gimbal Top Board cannot communicate with OFDM board

ad 1:
Easy to check - remove the SD-card.

ad 2:
Easy to check - if this is the case this case, gimbal will be limp.

ad 3:
If you cannot take photos, that would mean Ambarella chip on that board is not booting. Possible causes:
a) Buck converter which powers Ambarella chip could be damaged.
b) NAND chip which stores software for Ambarella chip could be de-programmed or damaged (most often case)
c) the Ambarella chip itself or its RAM chip is damaged - it is usually not worth trying to repair the board in this case

We don't know how to solve most of Ambarella issues, but we know how to get some additional logs from that chip.

ad 4:
Check the ribbon cable connecting the two boards, and connectors into which the cable is inserted. Often the connectors are ripped out of board during a crash.
 
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Thank you for this very helpful reply.

I had previously confirmed it was not 1, or 2, but I need to thoroughly confirm 4 (the ribbon connectors) as I noticed one of them had one wire smashed between the top gimbal plate and the aircraft shell when it was assembled. Could potentially be a bad connection there.
All camera functionality didn't fail simultaneously. First the FPV was on/off periodically. Then FPV remained off but other camera functions continued to work. Then camera stopped working but I could still access the camera controls on the DJI GO App but finally lost that also.

I'm hoping it is the ribbon cable. If not, then I would suspect the Buck Converter due to the way the functionality deteriorated. Any knowledge on how to test this? Is it worth replacing?

Thanks again.
 
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If not, then I would suspect the Buck Converter due to the way the functionality deteriorated. Any knowledge on how to test this? Is it worth replacing?
Yes, buck converters are easy to test with a multimeter, and easy to replace.
Some test pads on the board are marked with voltage values. Those are outputs of various buck converters. Check if all voltages match.

Ambarella is required for both FPV and camera recording/photos. Additionally there's DaVinci chip which is responsible for FPV only.
When only FPV stops working, the issue is DaVinci NAND chip in most cases.

See my drawing for details:
Fixing flash in DM365 chip within Ph3 Pro gimbal
(the drawing is simpilfied, ie. it does not show NANDs and RAMs of Ambarella and DaVinci, and it does not show the buck converters)

If Ambarella starts booting and re-starts at some point, often people report that the LED on gimbal blinks in some pattern which repeats after less than 15 seconds. It is possible to connect to Ambarella via USB-to-TTL converter, or tell the chip to store logs on SD-card.
 
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I tested the ribbon cable and it turned out to be fine. I'm glad to hear the buck converter is easy to test and replace. I'll test the buck converter and if that is not the culprit I will likely replace the board. I will report back about my findings on the buck converter or maybe seek more help if I have have trouble with the tests. I need to get on to a more pressing chore at the moment. I appreciate your time.
 
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Here is a photo of the test points I found to test. They all showed less than 0.2VD below the market values except the one marked with an X which showed no reading. Does this present a clear indication of the problem (buck converter?) orTested points.jpg do I need to do some more testing?
Tested points.jpg
 
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Did you measured the resistor at end of your red line? Because the test pad is below "9".
Also, there are some "VCC" pads - you can test their voltage as well. And the 1V2 pad - means 1.2V.
 
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Thanks for pointing out the other testing pads. Here are the voltage readings I have now. The A95_3.3VD pad has no power so I believe this could be directly related to my problem. I haven't yet done any research on that yet so I don't know what circuit that might belong to.
Inked Test Pads.jpg
 
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The 1V2 should be 1.2V; if it's 12V, then it probably burned one of the chips. Hopefully you just made a mistake when placing the dot.

So the issue clearly is A9S_3.3VD.
Now, the buck converters are on other side of the board. Each of them has an inductor at output. There are 5 inductors in total. Check whether one of them is missing voltage, or whether any of them is shorted to A9S_3.3VD - I don't know which one creates that voltage.
The DAJ one creates voltages for DaVinci, so it is probably the source for your 1V2. One of the VUBIs creates 5V from the 12V it receives from ESC Center Board. The second VUBI - partial schematic says it creates 1V1, but that sounds suspicious.. maybe a mistake. Anyway the most likely source of your voltages is the National Semicon. double buck converter near sd-card slot.

The partial schematics are linked at bottom of this page:
Github OGs - WM320 Gimbal top board
 
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Okay, back to trying to sort this out.
I turned the board over and checked the voltage on most of the components. Nothing looked really strange until I got to the section I marked here on this photo of the board. The items outlined show no voltage and the three larger items showed nearly 17 volts. 0.0 and 16.9 volts is far out of line with the readings I was getting on the other component of the board. Does this new information give us a clear indication of what component is at fault?
 

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Nope.

Check where the traces go. I'd speculate you're measuring gimbal arm controller.
 

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