I think I might have finally resolved this.

Having a careful think about SupraGuy's comments, I resolved to head back to square one and test everything. First up, I swapped the Y stepper with a known serviceable item. I then went back through the Dozuki set up guide and checked that the end stops were all working.

I then disconnected the belt drive on the bed to see if the stepper would move as it should and if so in what direction.

Bingo the Y stepper was doing exactly what it should. I then reconnected the bed with a lot less tension on the belt and Home Y worked again.

Thanks to all for your help.

I have now done the changes to resolve the mirror image problem and again everything appears to be working in the correct sense.
I will now try a print of the offending item that started all this and let you know if everything is still happy happy joy joy.

@bearer Good spotting thanks. Have changed it back to S1 and appears to be working OK

@Phaedrux here is the relevant section of Config .g as it stands at the moment
; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.2 on Fri Jan 22 2021 13:39:52 GMT+1300 (New Zealand Daylight Time)

; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"Pierre's Core XY" ; set printer name
M669 K1 ; select CoreXY mode

; Network
M552 S1 ; enable network
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet
M552 S1 ; enable WiFi

; Drives
M569 P0 S1 ; physical drive 0 goes forwards
M569 P1 S1 ; physical drive 1 goes forwards
M569 P2 S1 ; physical drive 2 goes forwards
M569 P3 S1 ; physical drive 3 goes forwards
M584 X0 Y1 Z2 E3 ; set drive mapping
M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z3400.00 E420.00 ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00 ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00 ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I30 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1 ; set axis minima
M208 X300 Y300 Z300 S0 ; set axis maxima

; Endstops
M574 X1 S3 ; configure sensorless endstop for low end on X
M574 Y1 S3 ; configure sensorless endstop for low end on Y
M574 Z1 S2 ; configure Z-probe endstop for low end on Z

M122 returns: Reprap firmware for Duet 2 Wifi version 3.2 running on Duet wifi 1.02 or later

Now on to endstop set up and getting it to accept a 220v bed heater with a Thermistor that measures 138k Ohm

Having had a good read of the RepRap Dozuki, I believe I have answered all of my questions and amended the Bed.G file to make things work.
The probe is now working correctly and the machine is now working on its first test print.

DOH!!!!!!!!!!!!!!!!

Often it is the obvious mistake that will only get picked up by another set of eyes.

Thank you Phaedrux it is all working as advertised again.

Thanks David I will give that a try. Just need to build the board and then test it.

@Pierre52 Doh. Problem solved when i connected the bed Thermistor to the correct plug beside the bed heater.

@Phaedrux Aha the light finally comes on. Thanks for all your help on this.

@fcwilt . Than you Frederick I have finally got an explanation of what H2 does in the G90 command. I have been searching for this for ages and your explanations of H1 and H2 above finally made sense of everything. I was also having some fun getting my head around where and when if should be using G90 vs G91.

I have now rebuilt my Home all file and everything now works exactly as it should. No need for M594 any more.

The working Home all looks like this:

M400 ; make sure everything has stopped before we make changes

M915 X Y S2 R0 F0 ; set X and Y to sensitivity 2, do nothing when stall, unfiltered
M574 X1 Y1 S3 ; set end stops to use motor stall
G91 ; use relative positioning
G1 H2 Z5 F1200 ; Lower bed 5mm

G1 H1 X-325 F3600 ; Move X to Home
G1 H1 Y-325 F3600 ; move Y to home

G90 ; Use Absolute positioning
G1 X150 Y150 F4000 ; Move head to center of bed
G30 ; Lower Head, Stop when probe triggered and set Z to trigger height

G1 X0 Y0 F4000 ; Return Head to Home

@fcwilt Hi Frederick. Yes I did cut the relevant parts into X Y and Z homing files. Your input has also significantly reduced the number of lines in each. Thanks again for all your help.

Cheers
Peter

@Pierre52 Doh. Problem solved when i connected the bed Thermistor to the correct plug beside the bed heater.

I have been modifying a printer with a Duet 2 board. On boot up the Bed Heater connected to E1 is showing a temp of -271 degrees.
The E0 hot end heater is showing the correct ambient temp.

If I swap the two thermistor plugs Bed Heat reads ambient on E0 and Hot end faults to -271 on E1.
This suggests that there is a board fault with E1 despite the fact that a close visual inspection doesn't show any physical damage
I presume that I can connect the bed thermistor to any one of the 5 spare thermistor pins 35 - 39 on the expansion socket. As there is only one pin for each of those five spare spots, I presume the other thermistor lead is connected to ground?

I have an existing Core XY using a Duet 2 Wifi that I plan to convert to a Voron 2.4. This of course will require 4 x Z steppers.
I assume that the addition of a Duet expansion board should allow this to happen.

I have tried searching for similar posts on this issue but most seem specific to the Duet 3.

Is this concept doable? and has anyone been there done that?

Cheers
Peter

@phaedrux thanks. I think I will play safe and use a separate Buck converter

@phaedrux I do not have data sheets for either fan. The other options are to connect it to the Panel Due 5v and GND. Other option is to wire a buck converter to the 12v PSU direct.

@phaedrux 1 x Cooling fan and 1 x hot end fan both 12V

@phaedrux Sorry Duet 2 Wifi 3.2.2. Planning on using Fan 2

Hi
I am planning to use a 3 Watt high power LED (700milliamps at 5vDC) to light my print surface.

I just want to double check that it can be powered from a spare Fan connector without problems.

Peter

DOH!!!!!!!!!!!!!!!!

Often it is the obvious mistake that will only get picked up by another set of eyes.

Thank you Phaedrux it is all working as advertised again.

Hi Phaedrux
Answers to your questions:

1. The white wire runs alongside the Hot end fans, thermistor and heater but none of these are active with this current round of testing.
2. The BL Touch was working 100% correctly before the LED changes.
3. For the LEDs I plugged signal leads for R G & B into Heater pins 4, 5 and 6 on the expansion board. These can be seen in the Photo. The LEDs have their own direct feed from the PSU and are linked through a Darlington Array (ULN2803) chip.

I have also sent the following commands with results as shown:

Power On - BLT cycles and LED goes orange.
M199 - Z Probe at min stop
G92 Z50 DWC shows Z at 50
M119 - Z Probe at min stop
M280 P0 S10 Probe extends blue led illuminates
M119 - z Probe at min stop

M280 P0 S90 - probe retracts red led illuminates
M119 - z probe at min stop