I found that the 220 ohms resistors in 9X are extremely sensitive to any handling.
In almost any radio I migrated until now, I has one or two broken resistors after migration, some from pins not related to wire soldering.
For me a stuck switch after migration led me automatically to measure the corresponding resistor, and always I found them interrupted.
Check yours and see.

Thanks for quick reply

Checked resistors and it seems that resistor with MISO have fried (yellow line in picture in post #13)


Have you changed fried resistors or lived with constantly active switch/switches?

Changed, not my radios, fellows would kill me

In this case 9x is my own, so no risks to get killed

With my equipments changing it's like poking tiny pebbles with crowbar. So maybe I just live with it. At least I know the reason.

Is there any tool out there that can actually read the RSSI / Voltage alarm levels?

I was trying to understand if my 9X mod had any problem or not as the radio doesn't read them. But also I can't read them using module back pins.
Ended doing some code to debug and testing with my other DIY kit I have in my 9C and the same... can't read them.
I'm sending the 11byte frame that should trigger them to be output but nothing happens.

See my post previous page about the output pin shorted to ground, maybe you query packet don't reach the module

That's what I was trying to determine. But on my second radio, a 9c, I have installed a DHT kit, so there's no mods at all.
I added a BT dongle but it's plug straight into the DHT telemetry port and receiving data works fine.

Problem solved!
It was related to bad documentation from FrSky about their protocol... I need to use a frame format that's not mentioned in their docs. Only digging around the web I ended up finding mention to it.

It would be good that they provided proper documentation.

What do you mean?
What is more exactly the wrong info ?

In the doc at the FrSky site to query for the ADC + RSSI alarm thresholds it says to use:

0x7E 0xF8 0x00 ...

But this is not correct it should be instead:

0x7E 0x0F1 0x00.....

Well actually this will only return RSSI alarms not ADC.

Btw, thumbs up for FrSky support. I sent them an email about this and I got a reply just a few hours afterwards.

Telemetry problem solved as well, turns out I was using a resistor too high in the RX line.
I can now read the alarm values.

Does someone have a picture of the FrSky DIY PCB WITh telemetry?

I own the module V8HT without telemetry and I wonder if I can mod it somehow to support it?

Originally Posted by SlimTom

Does someone have a picture of the FrSky DIY PCB WITh telemetry?

I own the module V8HT without telemetry and I wonder if I can mod it somehow to support it?

I'd say that it is not possible as you won't be even able to make it talk with the RX's that have telemetry support.

The schematics are almost the same, assuming you can succeed to flash DxT firmware using upgrade lite and the four icsp pads from bottom left corner... you will miss the buzzer circuitry for acoustic alarms, and the serial output for display.
Will be a muted telemetry module, not worth the hassle.

Originally Posted by IceWind

I'd say that it is not possible as you won't be even able to make it talk with the RX's that have telemetry support.

That's my dilemma - are the modules the same only without some cables and switch - or this are two completely different modules. A picture of TX telemetry capable module PCB would be helpful...

you will miss the buzzer circuitry for acoustic alarms, and the serial output for display.

I plan to connect it to 9x display and voice module anyway....