Problem with hp designjet 750c

following problems hp designjet 750c

- Cutter cuts initial cut after power up but fails thereafter.
- Check cartridge path" error after overhaul, replaced belt and general clean. Carraige runs smooth when handled, when powered up up moves then juddersand gives the error message. Is this a problem with the encoder strip?
- 2 plotters with errors pointing towards friction on carriage path although they are both running smoothly on rails. Both sets of rails have been lubricated.

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