N2521

Ik heb hier de engelse Philips Service Information A77-136 voor de N2521 dd. 1977-12-29 met de volgende info:

Some apparatus have alien noise of high frequency. This is caused by the resonance of the tacho-disc inside the motor. This fault may occur in motors marked 646 up to 713. For some apparatus the fault can be remedied by changing the tape speed (R467), for other apparatus the motor has to be exchanged From motor code 713 and up the tacho disc has been changed