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This may have been discussed but when I searched the issues didnt seem the same as what is happening with mine.

I have a Rostock Max ver 1.

My hot end became loose from the ceramic sheath and I replaced it with a new hot end.

The new hot end is a different length than the old one.

How do I adjust for the added length?

by the way if i start a print it slams into the glass... scary!

Normally use mattercontrol but have been trying to communicate through repetier to no avail

I believe it's covered in the manual, which is available for download.
Basically you need to adjust the X Y and Z max length settings in the EEPROM settings, I think the latest repetier has a quick way to do it from the LCD, but I don't use it.

yes, i found that part of it however i cannot connect with repetier. it says its connected but no manual controls or gcode commands respond

Check your com port in device manager.

If that doesn't work, see if you can connect with Arduino IDE and re-flash it.

The comport is correct since it is the same in mattercontrol and I am able to control and print from mattercontrol

Currently its COM3

Love your avatar!

If the com port is correct than the baud rate setting in Repetier Host must be incorrect.
The baud rate has to match what is in the Repetier Firmware.

adjusted the baud rate to 128000 and was able to connect