Can't get FrSky Passthrough working (4.0.5)

[Alberto_Ds]

Hi, I also have a similar configuration and the same problem, even putting 0 on serial option unfortunately I have not solved. Omnibus nano F4 v6.0 and radiomaster
Here are the tests I did, can I try anything else? Thanks

Some soldering required

I bought a couple of these max3232 cheap china boards from ebay and the first one has worked for about a year and does not get hot, never tried the second one till this week. It was not working, so I put a scope on it and found some of the through holes on the board (where you connect the wires to on the end of the board) were not making contact. I had soldered the two diodes to the bottom this time and the wires to the top. And the diode that is connected to the S.Port was open (because of the…