I'm having an issue with a MinimOSD which is integrated into the HGLRC all in one pdb+fc+osd (banggood link). Video + osd look fine until I either turn my tx on (ie the rx gets activated) or if I connect the usb port to my laptop. Then the video glitches completely or just goes black totally. If I have my vcam and vtx connected directly I don't have these issues so I'm ruling out the vtx or the vcam being broken. Any suggestions? Seems that it might be a 5v voltage supply thing... Not sure how much I can influence since the OSD is integrated. Any tips are greatly appreciated!

You can see the issue here:

I've read this somewhere:
vTx and Camera connected on the same GND (on minimOSD)

You can't have a grounding issue, or in other words - if it is a grounding issue, than this board is designed poorly.

Things i would do:
- Check rx wiring or if signal cable doesn't have a short somewhere or are wires soldered properly on rx side (easy to mistake there)
- Just for test use another source of power for rx
- Add a cap on 5v close to rx
- Check if 5v reg isn't loaded too much - from what i see you have fc, osd, rx and cam on 5v. Or is that eachine also 5v?

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I've watched again - I see that eachine gets lipo V. Can you plug camera to eachine 5v out instead of PDB? Also check rx wiring as above.

(02-Nov-2016, 08:33 PM)KonradS Wrote: You can't have a grounding issue, or in other words - if it is a grounding issue, than this board is designed poorly.

Things i would do:
1 - Check rx wiring or if signal cable doesn't have a short somewhere or are wires soldered properly on rx side (easy to mistake there)
2 - Just for test use another source of power for rx
3 - Add a cap on 5v close to rx
5 - Check if 5v reg isn't loaded too much - from what i see you have fc, osd, rx and cam on 5v. Or is that eachine also 5v?

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I've watched again - I see that eachine gets lipo V. Can you plug camera to eachine 5v out instead of PDB? Also check rx wiring as above.

Thanks a ton for those tips! I've numbered them for easy answering

1 - rx totally works as intended, no wrong connections there
2 - great idea
3 - also great
4 - vtx is powered directly from lipo. Alternatively I could put it on the regulated 12v but related to my issue I don't see the difference between the two. I could power the cam through the vtx since it does 5v regulation as well, but then I wondered if the strength of the vcam video signal might not match the 5v signal that minimosd is expecting, if that makes any sense. Is that a valid thing to worry about?

Well, numbers 2 and 3 are actionable, I'll get right on it!

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(02-Nov-2016, 08:13 PM)mxclouti Wrote: I've read this somewhere:
vTx and Camera connected on the same GND (on minimOSD)

Yes, I've read that too. Seems to pertain usually to the more common issues of the OSD disappearing from the camera image on high throttle punches. That's not really my current issue. In any event, I've tried various wiring methods and common ground was certainly one of them. No difference.

(02-Nov-2016, 08:33 PM)KonradS Wrote: Things i would do:
- Add a cap on 5v close to rx
I've watched again - I see that eachine gets lipo V. Can you plug camera to eachine 5v out instead of PDB? Also check rx wiring as above.

LEGEND! I added the first cap I could find which is a 470uF electrolytic cap (rated at 24V; more than good enough for the 5V of the RX) and.. no more glitchy glitchy! The videofeed still goes all-black when connecting usb to laptop but who cares.

I've got the cam powered from the 5v out of the eachine vtx. No issues with the osd stability. All's well. 

Man, I wish I had an oscilloscope *and* knowledge of how to interpret its inputs to just understand what the hell the capacitor does that prevents this glitching state. And ideas?

update: I switched the 470uF with a 10uF (smaller = lighter = better) but that didn't cut it, the glitching returned. Sticking with the 470uF.

No idea why vid cuts off with usb plugged in. If that was a f1 board i'd guess it turns osd off to free uart port for the fc... But..its f3 right?

Is that a regular electrolytic cap? If so, you can try a smaller low esr one (look for panasonic low esr caps). Those react to noise faster than regular.

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About the caps - they act like small batteries. Charging on voltage spikes and releasing the charge on dips. This way entire line gets smoothened out.

One of the people from RotoRev (the designers of this board) said that connecting USB overrules the OSD. I guess what he means is that the usb serial port is shared with the OSD and connecting the USB switches to the usb by default. This does support the fact that all video will go black and after disconnecting the usb the video comes back and minimOSD displays its startup procedure. It's an F3 board yeah, so not sure why that was necessary.

I'll look for low esr caps, thanks.