Welcome to the SeeMeCNC Community

OK, so I don't remember the exact reason why (it was sometime before the sun came out in spring), but I got the bright idea to upgrade my RAMBO to the Repetier 091 firmware...and it's gone poorly. I used the firmware linked to in the downloads section. (It seems the software for V1 and V2 printers goes to the same place) Now, it seems like the printer doesn't know where the head is. If I set a new Z = 0.00 height, and then send a G28 command, the printer thinks Z = 767 or so mm and not the normal ~ 365 mm. I was fairly comfortable with the old calibration method where the Z = 0.00 position was set by changing the Z_MAX value in the EEPROM, but I shouldn't have to mess with that and should just be using the set Z = 0.00 feature on the printer itself, right? In any case, that doesn't explain the huge difference in what the printer thinks is the Z height when I send it G28. I was thinking it might be something I need to adjust in configuration.h before I upload it, but I'm not sure.

Any help is appreciated.

Thanks

Did you follow the manual? It's a bit different from the V1.
I've one of the last manuals for the V2 and repetier host. If you need it let me know.
I'm not near a pc right now.

Also, does your eeprom z height match your printer settings? You need to change that one too

The V2's have different pulleys and depending on how old the V1 is, theRambo boards at the time were limited to 8x microstepping. As a result the steps per mm will be off, you can set them in the EEPROM.
If you have a V1 with 16 tooth pulleys and 8x microstepping. The correct value is 53.3333.
If you have 20 tooth pulleys it's 40.
You'll also have to set the extruder steps per mm mines at about 49
The other change in th 0.91 firmware, is that after homing the axis back off the limit switches by 5mm THEN get set to 0 so you'll have about 5mm less ZMax when you done.

Polygonhell wrote:...
The other change in th 0.91 firmware, is that after homing the axis back off the limit switches by 5mm THEN get set to 0 so you'll have about 5mm less ZMax when you done.

Does this mean that the 0 position is set at the top and Z_Max is at the build plate?



Also, my machine has:

20T pulleys - I replaced the old ones some time ago.
An EZ Struder - When I replaced the pulleys, I did this as well
A v1.1 Rambo - I don't know 100% how to tell which version I have, but my instructions file has the sheet for v1.1 in it

I haven't used Repetier Host for a good long time. I like some of its features better, but overall, I've had more success with Matter Control. The calibration/setup procedure I followed before updating the firmware was a mashup between what's in the V1 and V2 manuals. With the firmware upgrade, I'll follow the V2 manual.

I do miss the display of the nozzle position that was displayed on the printer's LCD with the earlier firmware.

I've changed the EEPROM settings, but unfortunately real work calls...I'll have to get back to it tonight

Does this mean that the 0 position is set at the top and Z_Max is at the build plate?

No zero id still on the build plate, sorry for the confusing description, it sets the Z to ZMax after moving off the limit switches.
a V1.1 would have 16x uStepping, so steps per mm should be the same as a V2 which is 80

Thanks! It's now moving like it should.