7i76D TB3 power?

You can install mesaflash using the instructions at the bottom of this page:

github.com/LinuxCNC/mesaflash

That's done and seems to be working. But seems to be reporting a similar error.

muzzer_linux@LinuxCNC:~$ mesaflash
Mesaflash version 3.4.0~pre1
Configuration and diagnostic tool for Mesa Electronics PCI(E)/ETH/EPP/USB/SPI boards
Try 'mesaflash --help' for more information
muzzer_linux@LinuxCNC:~$  mesaflash --device 5i25 --readhmid
You need root privileges (or setuid root) to access PCI hardware
No 5I25 board found
muzzer_linux@LinuxCNC:~$ sudo  mesaflash --device 5i25 --readhmid
[sudo] password for muzzer_linux:       
Configuration Name: HOSTMOT2

General configuration information:

  BoardName : MESA5I25
  FPGA Size: 9 KGates
  FPGA Pins: 144
  Number of IO Ports: 2
  Width of one I/O port: 17
  Clock Low frequency: 33.3333 MHz
  Clock High frequency: 200.0000 MHz
  IDROM Type: 3
  Instance Stride 0: 4
  Instance Stride 1: 64
  Register Stride 0: 256
  Register Stride 1: 256

Modules in configuration:

  Module: DPLL
  There are 1 of DPLL in configuration
  Version: 0
  Registers: 7
  BaseAddress: 6000
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: WatchDog
  There are 1 of WatchDog in configuration
  Version: 0
  Registers: 3
  BaseAddress: 0C00
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: IOPort
  There are 2 of IOPort in configuration
  Version: 0
  Registers: 5
  BaseAddress: 0000
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: MuxedQCount
  There are 6 of MuxedQCount in configuration
  Version: 4
  Registers: 5
  BaseAddress: 2600
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: MuxedQCountSel
  There are 1 of MuxedQCountSel in configuration
  Version: 0
  Registers: 0
  BaseAddress: 0000
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: SSerial
  There are 1 of SSerial in configuration
  Version: 0
  Registers: 6
  BaseAddress: 4B00
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 64 bytes

  Module: StepGen
  There are 5 of StepGen in configuration
  Version: 2
  Registers: 10
  BaseAddress: 2000
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: LED
  There are 1 of LED in configuration
  Version: 0
  Registers: 1
  BaseAddress: 0200
  ClockFrequency: 33.333 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

Configuration pin-out:

IO Connections for P3
Pin#                  I/O   Pri. func    Sec. func       Chan      Pin func        Pin Dir

 1                      0   IOPort       SSerial          0        RXData6         (In)
14                      1   IOPort       SSerial          0        TXData6         (Out)
 2                      2   IOPort       SSerial          0        RXData5         (In)
15                      3   IOPort       SSerial          0        TXData5         (Out)
 3                      4   IOPort       SSerial          0        RXData4         (In)
16                      5   IOPort       SSerial          0        TXData4         (Out)
 4                      6   IOPort       SSerial          0        RXData3         (In)
17                      7   IOPort       SSerial          0        TXData3         (Out)
 5                      8   IOPort       SSerial          0        RXData2         (In)
 6                      9   IOPort       SSerial          0        TXData2         (Out)
 7                     10   IOPort       MuxedQCountSel   2        MuxSel0         (Out)
 8                     11   IOPort       MuxedQCount      1        MuxQ-A          (In)
 9                     12   IOPort       MuxedQCount      1        MuxQ-B          (In)
10                     13   IOPort       MuxedQCount      1        MuxQ-IDX        (In)
11                     14   IOPort       MuxedQCount      2        MuxQ-A          (In)
12                     15   IOPort       MuxedQCount      2        MuxQ-B          (In)
13                     16   IOPort       MuxedQCount      2        MuxQ-IDX        (In)

IO Connections for P2
Pin#                  I/O   Pri. func    Sec. func       Chan      Pin func        Pin Dir

 1                     17   IOPort       StepGen          0        Dir/Table2      (Out)
14                     18   IOPort       StepGen          0        Step/Table1     (Out)
 2                     19   IOPort       StepGen          1        Dir/Table2      (Out)
15                     20   IOPort       StepGen          1        Step/Table1     (Out)
 3                     21   IOPort       StepGen          2        Dir/Table2      (Out)
16                     22   IOPort       StepGen          2        Step/Table1     (Out)
 4                     23   IOPort       StepGen          3        Dir/Table2      (Out)
17                     24   IOPort       StepGen          3        Step/Table1     (Out)
 5                     25   IOPort       StepGen          4        Dir/Table2      (Out)
 6                     26   IOPort       StepGen          4        Step/Table1     (Out)
 7                     27   IOPort       SSerial          0        TXData0         (Out)
 8                     28   IOPort       SSerial          0        RXData0         (In)
 9                     29   IOPort       SSerial          0        TXData1         (Out)
10                     30   IOPort       SSerial          0        RXData1         (In)
11                     31   IOPort       MuxedQCount      0        MuxQ-IDX        (In)
12                     32   IOPort       MuxedQCount      0        MuxQ-B          (In)
13                     33   IOPort       MuxedQCount      0        MuxQ-A          (In)

muzzer_linux@LinuxCNC:~$
 
Should I try to reinstall LinuxCNC 2.8.2?

OK that looks right.

That is firmware for a 7I85 on P3 (the external DB25F connector)
and a 7I76 on P2 (the internal header) Is that how you have things
connected?

Yes, that's correct. It was working fine, up to the point I reinstalled Linux and Linuxcnc on a new SSD. I'm wondering if there's something in the INI or HAL files that isn't configured correctly for the new installation. I copied the folders over from the old SSD and initially it seemed to work OK.

Upload here the .hal and .ini files so we can have a look.

I wonder if the different RT used in this new install could be the issue (now Mint 20, was 19 previously)? Perhaps there is a reference to it somewhere in the ini or hal files although I've had a good look and can't see anything.
 

Dont know if this is the issue but you only have one serial port loaded in your hal

loadrt hm2_pci config=" num_encoders=4 num_pwmgens=0 num_stepgens=2 sserial_port_0=00xxxx"

Looks like it cant load the 5i25

After looking at the Mesaflash data, I would guess that there is a hardware issue on the 5I25/ PCI bus. Possibly a dirty slot or 5I25 pins or the card is not full inserted. (like you mentioned originally)

OK thanks for looking into this. I'll take it apart carefully and ensure it's all correctly assembled. I'll let you know what I find - once I've had a chance to get into this. Been a busy weekend on many fronts.