This is on a Fettec FC/4 in 1 ESC but I'd imagine the principles are the same as betaflight. 

The other day I soldered a new XT60 wire to my 4 in 1, as the old one got chopped up pretty badly.  Conformal coated where I had soldered, since the rest of my board is coated as well.  Today I went to plug in and I get white and black lines across the display, no OSD or anything. 

The VTX is a Unify Pro so it takes up to 26V.  I tried running it off the FC's BEC power as well as straight from the battery leads on the 4 in 1, and I get the same results.  Removed the capacitor altogether, same results.  I checked the voltage on the battery leads and it's showing the proper voltage.  Everything else works - motors, everything.  The VTX also powers on just fine, I see the LEDs.

I took a known working VTX off another quad and soldered it up, but instead of black and white lines, I get just black.  Nothing else.  I'm starting to wonder if my FC or ESC has a problem. Any other ideas?

Try taking your cam wire to the vtx, take the FC out of the equation. If you get perfect video, the issue is the FC OSD chip. If you still don't get video, then your cam is the issue (Considering you have two vtx's used

OSD chip is the likely cause.

Thanks guys, I just did more testing and I believe it's both the cam and OSD chip somehow. I wired the cam direct to VTX and I just get black. When I wire the cam to the FC I get the black and white lines.

I tried a brand new camera and I get perfect video when connected direct to VTX, but nothing when wired to the FC.

ouch. that sucks. they do make OSD boards you can buy. No idea what they cost and what they involve wiring up wise but it's probably cheaper than a new FC, especially these days.

If the camera supports voltage OSD function then thats all you need rather than buying a new FC or external OSD boards.

Or setup voice prompts on your radio for voltage etc.

Electronics are going to fry at any point in time. No guarantees if a new FC will last long either.

Just patch it up and fly if you can.

(10-Oct-2022, 12:27 AM)kafie1980 Wrote: If the camera supports voltage OSD function then thats all you need rather than buying a new FC or external OSD boards.

Or setup voice prompts on your radio for voltage etc.

Electronics are going to fry at any point in time. No guarantees if a new FC will last long either.

Just patch it up and fly if you can.

That's right - I keep forgetting about that, and I run a Foxeer Predator so I'm sure it has that.  Good thought, Kafie!