Novel problem with ET5 Pro

[Indy UKCM]

As you know I recently upgraded my 5X to a PRO, and installed Marlin (Thanks DV for the Vid)
However a slight problem has arisen, I think it is Probe related

Bed is levelled. Print resolution 0.2
It Homes at Z 0
When I start to print it goes thru its homing process again, as it does. But comes back with a reading of Z 0.7
It then returns to the edge to lay down the prime, then proceeds to center to start print and slams into the bed

Also noticed that when a print finishes, the board loses all memory of having a Z Probe and slams into bed on Home command

[Ender5r]

Just speculating: is it possible an M500 & M501 right after the G29 in the start code, and maybe another 1 in the end code help? Or, as someone else posted about, is it possible the leads from the probe need to be shielded?

[Indy UKCM]

Well that's my 5 Pro put on the shelf for the time being.
One of the lugs on the Y belt has popped off. And after fitting a new one, I can't seem to get the right tension on the belt without mechanical aid
Printed the usual Calib Cube and it's skewing in both directions on the Y axis
Prints fine up to the bottom layer of the X and Y, then skews rearwards to the middle of X and Y then straight for a few layers then skews forward for rest of cube

But what has got me thinking, is it might not be the belt. It only seems to kick at sudden change of direction with print ie Jerk. Specially when it is short movement for infill

Back to my old workhorse Original A8

[Ender5r]

Just a thought: did you turn eccentric nut on the Y Axis to its minimum position before installing the belt, pull on the end pulley by hand while tightening the bolts, then use the eccentric nut to add final tightness?

[Indy UKCM]

I'll give that a try, didn't know the nuts had any part of the belt tension, thought they were just to grip the track

[Ender5r]

The larger wrench that comes with the Ender fits the eccentric nuts. The 1 you want is at the front, right of the printer. I think the easiest way to back the nut off is to:

1. turn it so the belt loosens. Keep going until it's at its loosest;
2. if needed, replace the belt;
3. loosen the bolts that lock the idler wheel assembly;
4. pull the idler wheel assembly so it's pretty much as tight as you can by hand;
5. while holding the idler wheel assembly tight, tighten the bolts down;
6. finally, use the wrench to turn the eccentric wheel, this time to tighten the belt to the tension you want. I wouldn't go too tight.

Hope that helps (and is clear).

[Indy UKCM]

The idler assembly on the ET5 is welded in place and cannot be adjusted
You can only adjust the belt tension by moving the stepper motor in the base frame. Similar to adjusting the X belt tension

[Ender5r]

I can't believe I was so stupid/forgetful. I read "5 Pro" & immediately my mind said, "Ender 5 Pro". Duh! I've never seen an ET5 of any kind, so I have no idea how to adjust belt tension on 1. My bad. Sorry.

[Indy UKCM]

Found the issue with the Y axis stutter .... it's the belt ... see pic

Now I just need to fit a new one.
Luckily I have some of the reinforced GT2 belts from building other printers
Will have to loop them round the Bed Points as don't have any more of them lugs

[Ender5r]

Well, that don't look right

[Indy UKCM]

Ye, tell me about it.
I was doing some under bed cleaning and as I moved the bed back by hand I noticed a bulge on the belt.
On closer look, it looked like one of the ridges had popped off and was just attached on 1 piece

I've changed the belt, but with no clip, I've had to use the old fashioned Zip-Tie method.
As a result of this I have lost 10mm on the length of the Y axis, and had to add a clip to extend the Y endstop position

[Ender5r]

You can make a clip out of a piece of copper or brass tubing. You may be familiar with the soft copper tubing that's often used to hook up furnace humidifiers. It's a softer tubing that can be bent by hand. If you cut off a 1/2" piece of it, you should be able to use pliers to crush it around the belting.