I bought a RR a couple months ago and the left castle door will not open. In diagnostic mode, the switch registers and the right door opens fine, but the left door remains close and a grinding noise can be heard. I have not taken the castle playfield off to inspect, I wanted to get some ideas from this forum first. Thanks.

Thanks for the tip. I'll go ahead and take off the Castle playfield and check it out.

Problem Solved - I had time today to pull off the castle playfield and nothing really looked like there was a problem. I loosened and re-tightened the set screws and put everything back. Surprisingly that is all I need to do to fix the door. Everything works well now.

A couple weeks ago I started to have a second problem with the Castle Doors. In this new case the left door quit closing and stayed 1/4 open all the time. In test mode and during gameplay the door would open fully but never close more than the 1/4 open. I removed the Castle Playfield again today and found the hex screws that attach the motor to the main bracket had come loose and were not letting the door mechanisms clear the opening lever. I tightened the hex screws with locktite and then locktited the other hex screws that attached the doors to the shaft (my first problem) and put everything back together.

After putting the playfield back on, the doors opened and closed perfectly. Unfortunately I caused a new problem with the door not resetting after registering a hit. I pulled the upper playfield off again and found that the closing spring which I had to pull off to tighten the motor hex screws was too loose and did not pull the door shut every time. I pulled and bent as much slack out of the spring at the connecting loops which was enough to shut the door every time.

Hope this helps others.