Which model is correct, which is specified in the topic title, or maybe DJ T520?
Are the cartridges original?
Try replacing a set of cartridges, rather than one at a time
About 53.1:10, the encoder is not the reason, imho
Do you run
2.5 OOP sensor diagnostic from
Support Menu?
What about the OOP sensor flag and the FFC cable? Сheck also that the sensor is assembled correctly. Next in line is a Bundle board and Main PCA.
But if the motor does not work, run
2.2 Paper servo