Yes, same as MZ-6 released in 2001, has black plastic gear as shown in the above photo. These motors are taken out from failed MZ cameras. The plastic gear is not melted, just split at the center hole and can no longer hold on to the motor shaft. I have not seen any melted plastic gear but it is possible. If the gear splits in the middle of a cycle, the motor will continue running at 15K rpm if the camera is not immediately turned off, the friction between motor shaft and the pinion would generate sufficient heat to melt the plastic. Removing the bottom cover of the camera, you can easily see the mirror motor and the gear. If it is stamped: "PENTAX CORPORATION Made in Japan", most likely you'll have brass gear. The other two motors (one for focusing, another for transport film) are equipped with brass gears. I don't know why Pentax engineers would choose plastic gear for the mirror motor. The gear is 3.75mm in diameter; the center core area is very thin and would not be adequate to take the torque for flipping the mirror. I've opened two MZ-60, both have brass gear and stamped "PENTAX CORPORATION Assembled in Philippine". So when you are in the market for a MZ camera, look for the marking shown in the photo below. If it is stamped "ASAHI OPT. CO. LTD.", you will have to remove the bottom cover to see if the mirror motor gear has been replaced or not. If it is not, don't buy it.
Last edited by violini; 05-10-2019 at 07:02 PM.