Collins TCS 12

TCS-12 TX and its little power supply. The transmitter is working in its original state except that the vfo jumps enough to make CW a little rough. I wanted to use this for the straight key night and had it on the bench all the day before with very little drift, and no jumps. The minute I put it on the air in the evening it started  jumping, so now I need to get the inclination to find the problem. I have  yet to work up the interest to do anything with the receiver other than mount it next to the transmitter. I bought a total of three of the transmitters to get this one back to 'close to original condition and specifications'. I have the full development manual for these radios.