Kenwood KDC-75R Repair and Code disable

[jonno6766]

A friend on a pension has asked me to repair her car CD receiver and disable the code feature so she can use her mp3 player in Valet mode. The car was given to her and the code and users manual were not supplied with the vehicle. The CD is reading CDs intermittently and only after driving some distance with the receiver and amplifier running. I suspect this is due to a weak lazier that only operates when the temperature of the unit is well heated. The receiver is working well and so is the amplifier section.

Due to the age of the unit, the instruction and service manual is no
longer available. Servicing is only only done through the manufacturers. I'm a sound engineer and motor mechanic so the data will help.

Thank you.

Jonno