@phaedrux Once I figure out how to post pictures I will upload some

Found the problem.
It was the M566 instantaneous speed change set to slow it was set to 60 now its 600 and all is well.
Machine now very quiet and surface good.
It is strange that it printed ok on the diagonal but as soon as it was aligned withe axis and both motors needed to print a straight face on the y axis the problem showed up.

Firmware is 2.01 printer is a cross between a Dbot and a Hypercube

Art

I have just discovered if I dissable bed compensation the problem disappears.
So what causes this?

My core xy printer driven by a duet wifi has been printing large parts on the diagonal axis for weeks without a problem.
However last night I printed a rectangular part aligned in x,y. As it was printing along the y axis I noticed it was leaving perfectly aligned verticle lines 26mm apart. At these lines you can feel the steppers pulse. (even the extruder motor)
I then printed the same part on the diagonal and it was perfect.
I have tried 2 duet wifi boards with the same results so I think it has to be configuration related.
Has anyone come across this or have any Idea what the problem may be?

Arthur

Thaks for your quick reply Mike that has sorted it.
I knew it would be something simple but just could not see it.

Regards

Arthur

As the bed was losing its position on power off due to the weight causing it to run down the leadscrews I have re-confured the z axis to use independent z motors.
I am using the E1 output for the second motor.
The problem is that the motors are not moving the same distance as each other.
Thankfully I removed the bed before testing.
I think it must be due to settings of the E1 output but have been unable to figure out what
Firmware is v2.01
Can anyone advise where I am going wrong?
Arthur

; General preferences
M111 S0 ; Debugging off
G21 ; Work in millimetres
G90 ; Send absolute coordinates...
M83 ; ...but relative extruder moves

M555 P1 ; Set firmware compatibility to look like RepRapFirmare
M564 H0 ; Limit axis
M572 D0 S0.18 ; Set extruder pressure advance.
M667 S1 ; Select CoreXY mode

; Network

; Drives
M584 X0 Y1 Z2:4 ; 2 Z motors connected to driver outputs 2 & 4
M671 X-80:480 Y200:200 ; Z lead screws are at (-80,200) (480,200)

M569 P0 S0 ; Drive 0 goes forwards
M569 P1 S0 ; Drive 1 goes forwards
M569 P2 S0 ; Drive 2 goes backwards
M569 P3 S0 ; Drive 3 goes backwards
M569 P4 S0 ; Drive 4 goes backwards
M350 X128 Y128 Z128 E16 I0 ; Configure microstepping without interpolation
M92 X800 Y800 Z3200 E95 ; Set steps per mm
M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
M203 X12000 Y12000 Z1200 E3000 ; Set maximum speeds (mm/min)
M201 X1000 Y1000 Z1000 E5000 ; Set accelerations (mm/s^2)
M906 X855 Y855 Z1200 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 X400 Y400 Z450 S0 ; Set axis maxima

; Endstops
M574 X1 Y1 S0 ; Set active low endstops

I have just found an extra M307 H0 line in my config.g. It was hiding in the stepper settings.
I have removed it and the bed heater is now working.

I dont know where it came from but I cant blame anyone but myself.

Thanks

Thanks Danal,

Yes I have an Identical set up apart from having the semicondutor relay connected in place of the bed heater so its looking like a board problem.
I have just removed the board and there is no visual sign of any damage. I could swap it with my other machine but dont think it will prove anything more.

I will contact the suppliers on Monday and see what they say.

Regards

Arthur

Just finished a new build 400x400x500 with a brand new duet wifi and there seems to be a problem with the bed heater. I am using a silicon bed heater switched with a SCR.
The bed temperature is showing 2000 which indicates a thermistor problem. When I swap the bed thermistor with the hot end thermistor the hot end reads room temp and bed still shows 2000C.
I am using the same configuration as my previous build which also uses a duet wifi.

Is there any other reason the bed temp would read 2000C apart from a faulty board?

Arthur