Mesa 7i85 Smart Serial – Only Channel 4 Works, Possible Hardware Fault?

Hi everyone, I'm having a problem with my Mesa setup and hope someone can help me figure out what's going on. My setup consists of: - Mesa 7i96S- Mesa 7i85- Mesa 7i84 connected to the 7i85 via Smart Serial (sserial) The 7i84 works perfectly, but only on Smart Serial channel 4 of the 7i85. I've tried connecting the 7i84 to other channels and adjusted the HAL configuration accordingly, but it only works on channel 4. I recently wanted to connect another Smart Serial device using an additional cable, but I couldn't get it to work either. So I decided to take some measurements directly at the 7i85. Measurements with power OFF: - Channel 4: Resistance between RX and /RX is approximately 120 Ω.- All other channels: Resistance between RX and /RX is infinite (open circuit). Measurements with power ON: Channel 4: - RX to GND: 2.7 V- /RX to GND: 2.7 V All other channels: - RX to GND: 0 V- /RX to GND: 5 V These measurements seem quite different between the working channel 4 and all the other channels. My questions: 1. Is this behavior normal, or does it indicate a hardware problem with the 7i85?2. Has anyone experienced a similar issue with the Smart Serial channels on a Mesa 7i85?3. Could the missing 120 Ω resistance indicate a problem with the RS-422 termination or transceiver circuitry?4. Is there anything I can check or repair myself, or does the board need to be replaced? Any advice or suggestions would be greatly appreciated! Thanks in advance!

Sounds like you have a 7I85S rather than a 7I85.
What does the lot label on the back of the card say?

Problem solved!
I bought the board as a 7i85 and never double-checked the exact model. After investigating further, I discovered that it is actually a 7i85S, not a 7i85.
This explains why only one Smart Serial channel was working and why the RX measurements were different on the other channels.So there is no hardware fault, just the wrong board.

Thanks for your help!