On 4/20/2012 2:18 AM, Mike S wrote:
Hey guys,
I posted here recently about a problem where the back tension arm on my VCR got pinned down by the left shuttle assembly during unthreading.

I've fixed that issue, and I've retimed all the gears. I'm pretty confident that the timing is correct, because all of the holes line up, and the unit can be easily threaded and unthreaded manually by turning the worm wheel. Everything seems to move as it should, when it should. (There's a possible exception with my right shuttle: It could possibly be off by one tooth, since the gear looks slightly different from what the service manual shows, and the arrows are unhelpful. However, moving this gear a tooth in either direction does not affect my current issue, and it's in the middle position of only three that allow the shuttle to easily move all the way to both ends of the VCR.)

However, I cannot get system control to understand that the system is properly unthreaded. Whenever I turn the power on, it tries to unthread. If I start the gears out unthreaded, the motor will encounter resistance, and the machine will error out. If I start the gears out threaded, it will unthread, keep trying to go farther, encounter resistance, and error out. If I disconnect the motor from the gears, it will time out, then error out. It's always the same error, 09-821, which indicates the system could not unthread in the specified time.

I've tried disconnecting the unit from power for hours at a time, and the stupid thing still thinks it needs to unthread. The mode switch doesn't use any levers or moving parts: It bounces light off of reflective tracks on the back of the mode gear, which is perfectly timed with the rest of the parts.

Does anyone have any ideas how to approach fixing this?

Could be mebbe you should be thinking about coming up into the 20'th
century and going DVD ??