The idler gear RXL0106 is part of REM0043 & RDG0206 assembly that is driving tape transport and cassette doors. Because it was made from semi-flexible material it might tend to crack during the time.
3D printed replacement part (gear only) was tested for correct operation.
RXL0106 replacement 
RXL0106 replacement
The part is compatible with following devices:
RS-BX501, RS-CA1060, RS-CH404, RS-CH909, RS-DC8, RS-HD505, RS-HD505ES, RS-HD515, RS-HD515PPS, RS-HD75, RS-HDA710, RS-HDA710PPN, RS-TR170, RS-TR270, RS-TR373, RS-TR474, RS-TR575, RX-DT75, RS-TR777, RS-TR97, RS-AZ7.
Replacement of RXL0106 gear – video by Alvaro Cerasi
Product is available in e-shop.
sarei interessato mandatemi il prototipo cosi lo posso testare sul modello TR575
mi devi scusare non mi sono dimenticato del video che ti o promesso ma o avuto del contrattempo e ancora non mi sono deticato sulla piastra del 474 quando lo farò ti manderò il video
Alvaro