X9D Plus 2019 SE not transmitting

[steig]

Hi,
I just purchased a used X9D Plus 2019 SE. It does not bind and shows 0 RSSI. The seller has been great and however this turn out, I am satisfied. If necessary, I'll purchase a new radio and part this one out for my needs and others' needs, but I'd like to get it running.

Quick background: It looks like the package was dropped hard because the three buttons on the left side of the display were displaced from the momentary switches with absolutely no cosmetic damage visible inside or outside. I opened the case and reseated the buttons and checked all the ribbon cables.

It will not bind with any receiver I have. I tried an xm receiver, an X8R and a S6 receiver. No bind - no RSSI. I reflashed from the transmitter. I'm on latest build.

I conclude the backboard is bad. How can I test to make sure it is that and not the main board? If I successfully test my DSMX module in the back, can I conclude that the problem is NOT the motherboard? I have multimeter and a slow 'scope. Also, I would appreciate knowing if the backboard is available in the US. HorusRC has it in CN, but of course I'd prefer not to wait...

[Kilrah]

It's most likely RF firmware mismatches between that radio and your receivers. Flash the radio's internal module to the version that corresponds to your receivers.

[steig]

It is not powering an OrangeRX DSM module either. I wonder if the Hall-effect sticks are compatible with my aging X9D (not plus).

[bob195558]

I upgraded my Taranis x9d with the Hall-effect gimbals and they work great.
I also use erskyTx for Taranis firmware.
I have been using it for a long time, you can find it here: http://www.er9x.com/

FrSky did have some troubles with some of there early internal modules.
I have found using the external modules works better.