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FPV Issues: Only Static, No Video

#1
Hello! I'm Dave, first time posting here on the forums. I been following Flite Test for a while and I'm stoked to join the community. I've been flying RC Planes (inspired by the good gents here) since 2012, and Quads since 2014. Recently I've run into an FPV issue on one of my quads I just can't figure out and all similar issue threads I've found here, on RC Groups and FPVlab all don't have any solutions. I'm desperately hoping someone here can help out.

My video was perfectly fine for the first two months I flew this quad (220mm Mini Quad, 2204-2300Kv Motors, LittleBee 20A ESC's, SPRacing F3 all on a Matek v2.1 PDB with RD9s rx) Everything flew great until one time I but it down in some brush after clipping a tree branch. My FPV feed hit all static on the way down, but when it came to a rest I still had video feed-static-y but still had a video. No visible damage, other than a bent stock mushroom antenna- (ground shielding was exposed)

After repairing the antenna (taped), then going out to fly, all I got was static on my goggles (eachine Vr-007's - cheap, I know, but, they've worked great for me so far) Scanned through all channels and still got nothing. I tried adjusting channels on the Vtx, still nothing. I tested for outside interference inside the house, outside, different locations, locations I've flown in before, and still just static.

So naturally, I thought it was just a broken antenna. I ordered more and waited. Well, they came in (a matching pair of CP antennas) and they didn't fix anything, so I thought it's got to be the Vtx, so I checked it: no burns or smell. It's a 600mw TS5828 with no LED's but it does warm up running (even with antenna). I noticed the plastic 5 pin connector on the Vtx was cracked on one side and It was still getting warm plugged in, but I figured it was fried and ordered a replacement for $13- no biggie right? This will surely fix it I thought.

Well, it didn't fix it. The replacement 600mw TS5828 behaves exactly the same way, warms up, nothing but static. I don't know if makes a difference but right after I tested this replacement for the first time I noticed that the ground wire from the flight controller to the PDB was loose, and I re-soldered it on. Then, when I was troubleshooting the replacement I also found a 5v LED wire touching the carbon fiber arm at the solder joint to the LED's under the motors, giving the entire frame power which I metered at 3.9v. Fixed it with some new solder now the frame reads a nice 0.00.

Now ruling out components:
I have everything powered off of a 11.1v 3S Lipo with the camera getting power and ground from 12v on the PDB and then running the video line back to the PDB - Where it then passes through the PDB, and out to the Vtx along with the Vtx power and ground from a separate 12v pad. Both of these outs from the PDB meter at 11.89v.


1. Camera
My feed is static, varying sometimes, thick white lines others, but never even the faintest of image from the camera.
From what I've read, a camera issue would make the screen broadcast grey or black, and I metered .39v on the video line into and off of the PDB. I've also tried to run the Vtx without a camera attached and still only get static, never black. I don't have a replacement to test, but I'm now starting to think I should pick a cheap one up to see, just to save my sanity.

2. Goggles
The Eachine VR-007's worked perfect with my quad before the issue and still work great with my buddies quad (also a 600mw TS5828) My channel scan will always pick up the other quad with ease.

3. Video Transmitter
Trying both of them with the same results makes me think my first Vtx wasn't bad in the first place! Like mentioned previously, I've never ran them with antennas off and they both warm up when plugged in testing. I've tried 4 different antennas at this point and nothing but static. I even spent an hour flipping through every frequency and channel on both Vtx's and nothing worked. When I move the antenna near the Rx antenna, the static changes sometimes, other times it stays the same, which makes me think it's some interference or ground loop issue? I just don't know. I ordered another replacement (200mw version this time with LED's) but i'm waiting a couple days for it to come in- As I've read these cheap Vtx's arrive dead sometimes.

4. PDB/Wiring?
I've double and triple checked the PDB for defects and cold solder joints, everything looks good. Metering all my connections everything is reading right under 12v, from the PDB pads to the ends of the 3 pin connector (camera) and the 5 pin (with only 3 connected: Red, Black, Yellow-video on the Vtx) The Vtx is very obviously getting power as it warms up when battery is connected, so I haven't replaced any wiring. From what I understand (I could be wrong) the PDB shares the ground on the board, would wiring the camera and vtx ground to the same PDB pad help? It worked previously with them on separate pads before this issue. I'm not running a OSD or audio.


So, if you can, please help. Is there something I'm missing?

Is there a possibility that I fried both Vtx's with the positive charge on the frame touching the antenna connector? Or with the ground loose from the PDB to the FC?

Is it possible I got a defective Vtx? (If my 3rd Vtx doesn't work I'm giving up on this theory)

Is it a broken camera? The exposed PCB on the back of camera looks a-ok with no damage visible.

Could it be the connectors or wiring to the vtx? I worry if the first one had cracked at the connector on the vtx that maybe the male end wired to the PDB is broken too? This will be my next step to fix, I'm just waiting for the third vtx to be sure because I'll have completely remove my receiver and led lights to get a clean path to solder the new wiring. My only hesitation with this is that the original Vtx connector cracked on left side by the red wire, but, the vtx's still get power.

I'd like to solve this, as I've only found dead ends with an issue like this online. I figure this is the best place to try it. Mega-Super thanks to everyone in advance. Thanks!
 

PsyBorg

Wake up! Time to fly!
#3
Most FPV systems will not go to a blue or black screen. You WANT that static instead. As the signal degrades you will not all of teh sudden lose your feed allowing you a few seconds to turn and get back into range or to clear what ever object is corrupting the signal.

Channel scan works great.. right up until it finds a close frequency in a different band to lock on to before it finds the strongest signal on the proper frequency. Many people have this issue of getting a close channel not the actual channels.

600mw vtx is huge and WILL get warm now matter what you do. The thing is that much power will cause a ton of reflections when in confined areas where the signal can bounce around. I fly on 25 mw and have no problems for my quad. Yes I might want a little more range at times but its not a necessity as that just means a longer walk when I crash .

You also have to be wary where you run your VTX signal wire between the Camera and the VTX. If it is over the FC or crosses the ESC wires NOT at a 90 degree angle you will be injecting interference.


To sum it all up I would start by checking the signal wire between the Camera and VTX and rerouting it away from as much as possible. I would also drop down to only a 200 mw tx tops. That will reduce reflection issues. You could also try left hand circular polarized antennas or one CP antenna and one patch. Personally all I use currently are a matched set of Aomway antennas and a freebie dipole as my diversity channel antenna on my goggles.

Hopefully some of those tips help you get a better signal and gets you back in the air.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#4
It's a 600mw TS5828 with no LED's but it does warm up running (even with antenna).
From this I infer that you ran the old VTX without an antenna while troubleshooting. That will kill a VTX in a heartbeat.

Did you run the new VTX without an antenna?

If so, I'm with PsyBorg. Try a 200 or 25mw VTX and never ever run it without an antenna.
 

PsyBorg

Wake up! Time to fly!
#5
Ohh good catch Cranial. If he ran a 600mw without an antenna it is more then likely equal to a slice of toast or at the very least seriously degraded.
 
#6
From this I infer that you ran the old VTX without an antenna while troubleshooting. That will kill a VTX in a heartbeat.

Did you run the new VTX without an antenna?

If so, I'm with PsyBorg. Try a 200 or 25mw VTX and never ever run it without an antenna.
I am also having these troubles though and I have a switchable vtx but it's brand new and have only tried it on 200mw.
I do however get the odd completely grey screen when flicking through channels.
 
#7
Hey guys- sorry for the late reply.

SOLUTION: My Fpv cam was dead. Swapped it out with a new one and it fired right up.

I never ran the vtx without a antenna on it- so it was fine.

To help others, depending on your vtx (like the Aomway Tx001 I'm currently using) there may be a off switch for troubleshooting the quad on the bench to not interfere with others video channels at events. Check your documentation for that, I've accidentally activated it and worries me until I figured it out.

All the advice is much appreciated! Thanks!