DraytonTom

Hi CMC

Thanks once again for your help.
I found the avrdude options this morning.
Going to flash 438.02 after I finish this post.
The firmware settings I posted where at the end of testing the x-axis in isolation(the problem was the same on both x and y axis and so concentrating on eliminating the problem on the axis with a single motor seemed sensible), hence why they are different between x and y.
The firmware settings don’t reflect ones that I would use to run a job. Normally the x axis settings would be set the same as the y axis.

I appreciate that Backlash is a much misused term. I am defining it as the error generated whenever the axis changes direction (due to mechanical slack in the system).
So for example if I moved the machine G21 G90 G0X1 I measured a movement of only .8mm, but a subsequent G21 G90 G0X2 moved the axis the correct distance.
Axis ended up at 1.8mm.
Reversing direction G21 G90 G0x1 resulted in the axis only moving .8mm again, so ending up at 1mm a G21 G90 G0X0 moves the correct distance and the axis ends up back at 0.
Changing the manner in which the belts where anchored at either end of the V-slot reduced this problem. I was under the impression that there was still a lingering problem, but it was a few months ago, and my notes and data dont make much sense to me now.
I suspect that illegal values I found in the TinyG when I first switched it on induced a form of paranoia and as such the last note I made was “reflash firmware”.
Hopefully, now I know how to achieve the firmware update, I will be able to make some measurements and everything should be fine.
Will keep you posted.
Many Thanks
Tom

Hi guys thanks for the prompt response.

CMC, apologies its a TinyG v8 Board, firmware build 412.01
Chmr, you nailed it, thankyou!

https://www.dropbox.com/sh/yqje28uos84uqtf/AADKtrKtHu38DtDTOttRPNWOa?dl=0

Yes I did restore machine specific commands after issuing the defa command.

I have just realised that the firmware I have been trying to upload is an older version.
According to http://synthetos.github.io/ Master is still 380.08.
Is it normal to ship TinyG with Edge firmware? Or am I misreading this?
I have now flashed the firmware quoted as Master, the upshot is that as soon as the TinyG boots, Motor 1-3 LEDs light constantly. I killed power as quickly as possible, will investigate further in the morning.

A bit more background.
I have a Routy CNC which is essentially a Shapeoko 2 built using V-Slot.
I was having an issue with backlash equating to .2mm in both the x and y direction in all parts of the machine bed. I was using a GRBL shield and decided to upgrade to a TinyG, that way I could eliminate the electronics as the cause.
I had been testing for backlash using a spring gauge and issuing direct gcode commands through coolterm and measuring the discrepancy between theoretical and actual movement(I was concentrating on the x axis only to reduce the number of variables).
Altering the method of anchoring the belts has made a significant improvement to the problem, but as I had already discovered that the TinyG was shipped with some invalid values (NUM maybe, I didnt record it), I wanted to reflash the firmware for my own piece of mind.

Thanks again Tom