3dr telem and minimosd not working at the same time

Having problem to make work both at the same time, Both work well alone…

I do have a Y connector going out of the APM with GND/+5/Tx/Rx going to minimosd and telemetry 3dr,

When each add-on plug seperately work fine, but together not working ether i lose 3dr telem or screen display on minimosd,

When 3dr telem work with GND/+5/TX/RX and adding minimosd with same Y (without tx on minimosd) going to APM = 3dr telemetry goes down no communication and minimosd work fine.

When Minimosd work with GND/+5/RX and TX and adding 3dr telemetry with same Y (including TX) going to APM = I lose minimosd screen display and unable to connect with PC to 3dr telem.

If someone know’s what i’m doing wrong?

APM 2.5.2
Minimosd extra 2.2

Check if you’re unplugging Tx from OSD, not Rx…
To make sure:
static.rcgroups.net/forums/attac … emetry.jpg

Thanks mkrawcz1

But i do unplug Tx from OSD when i add the Telem (as per your diagram) when both OSD and Telem are plug on the Y connector.

It doesnt seem to be the problem cause they both work fine all alone on the same Y connector respectively…

Meaning OSD work and display telem info from APM with only GND/+5/Rx without Telem module plug-in on the Y connector.

1- But OSD woulnd not displayed APM info if i would mix those Tx and Rx on OSD without the Telem on Y connector?

2- If i do mixte Tx coming from Apm to Tx on OSD (instead of Rx) will i damage something?

Thks in advance.

Still searching… :question:

Mixing Rx-Tx shouldn’t damage anything.
I’d look for reason between your wires :wink:

I try switching TX and RX without success, but I notice that i do not have a steady 5V on my APM, only have round 4,7V , maybe this is causing a problem…for sending telem info to both OSD an Telem.

Will work on having a steady 5V on my APM.

What do you thing?

P.S.: APM is giving voltage to GPS, Sonar, OSD and Telem.

That might be the reason for OSD problems, telem should work with limited output power even if powered under 4volts.

UREEEEEEKA my OSD just barked into life!! (and now I can rest)
I had to add a HEF4050 BP ,652,Hex buffer converter 3-15v 16pin
but Hey it worked.even after that I had a wrestle with the radios not
wanting to work correctly but that WAS the apm tx and rx lines being
crossed.Thanks to all those (and you know who you are) who have been suffering the
horrors of check and rechecking to no avail.these chips are very common and cheap
So if your in need of the details on how to connect it up email me OK
Cheers All,I’m off for a Fly Byyyy