I've fixed CTC-9 and 10 remote sets which are probably similar, but probably less complicated that yours. It looks like the same sort of set up, where there is only one motor, and what function it controls depends on which solenoid is activated. On my sets, there was a separate relay for the motor and for each solenoid, and one for the motor to go in reverse. These were located under the remote chassis.
Because you're using the wired in controls, the problem can't be an alignment issue. But I've needed to re-align every RCA remote receiver I've had. (I don't know why, but the Zenith remote receivers usually don't seem to need it, while the RCAs do.)
Anyway, assuming this is like a CTC-9 or 10 remote set, if you find the relay for the motor under the remote chassis, you should be able to see it trip no matter what button you press, along with the relay corresponding to whatever solenoid corresponds to whatever button you pressed. If you see the relays tripping like they should in each case, then the problem is probably hardened grease like Electronic M said, and not an electronic one. Here is a pic of the underside of my CTC-9 remote chassis, you can see the relays I'm talking about in the top left corner.
http://videokarma.org/attachment.php...6&d=1357321012
I didn't have problems with hardened grease on the remote CTC-10 I used to have, but I did on the CTC-9 I have now. On that set I actually had to take the motor apart. There was hardened grease around a bearing that shaft went through. I had to clean it and re-lubricate it. I cleaned it and the gears with some WD-40 and then put on some of that white grease in a can. It seems to have held up well, it still works and I fixed it back in Dec. of 2012.
If it's like the CTC-9 the remote chassis has its own power supply, so it is possible to power up the remote chassis, and not the rest of the set. When I was working on mine, I found it useful to be able to remove the whole chassis with the tuner, motor, and all those solenoids and gears on it, put it up on the bench along with the remote chassis, connect the remote chassis to the main chassis, and only power up the remote chassis. That way you can test the motor and all those solenoids where you can easily access them without actually having to run the set at the same time.
That's a great find, the Worthington is a really cool set.