While a typical problem of Technics/Panasonic tape drives is the RDG5772ZC gear, sometimes might crack also gear located at the opposite side of the tape drive (down side) – RDG5773Z.
Either the lock can be broken or the shaft.
Replacement gear was created using a precise 3D printer using durable Nylon material. Locking mechanism was replaced with a split pin to be less fragile
Replacent gear with split pin 
original broken gear 
Replacent gear and split pin 
Replacent gear and split pin 
position of the gear in the assembly
Schematic of the drive assebmly:
Part is compatible with following devices:
MS20, MS600, RS-CH550, RS-CH700, RS-CH900, RS-T9023, RS-TR210, RS-TR232, RS-TR252, RS-TR252PK, RS-TR262, RSTR262PK, RS-TR265, RS-TR311, RS-TR333, RS-TR515, RS-TR535, RX-CT990, RX-DS05, RX-DS35, RXDS620, RX-DS790, RX-DT07, RX-DT5, RX-DT501, RX-DT680, RX-DT690, RX-E250, RX-E300, SA-CH11, SA-CH150, SA-CH150PPK, SA-CH455, SA-CH455PK, SA-CH52, SA-CH55, SA-CH72, SA-DH66, SA-VC10, SU-CH80, SU-CH82, SU-CH90, SU-CH92, RX-DT501, RX-DT505, RX-C300, RS-TR157, GX-89CD, RX-DS620, RS-TR355, RX-DT707, RX-DS30P, SA-CH33, RS-B55, RS-955, RS-TR165
It might work also with other devices – just check your service manual.
Available for purchase in the e-shop.