For the vertical deflection you want to check 12V on pin 20 of U701 (better use the resistor nearby so you don't accidentally short pins). That comes from the 15V line through a voltage regulator based on Z601. So if you have 12V there you don't have to worry about the 15V source.
Also, check for 25V (or close) on the cathode of D603 (which is coupled to pin 2 of U601). if you have voltage there you know it's also on the anode (pin 9 of U601). You already checked that at TP205 but you need to make sure it's actually going to U601.
If voltages are OK, it gets more complicated as you need an oscilloscope to check U701 is sending out the vertical pulse to U601 (pin 3) or U701 may be bad. Double check C603 in line with the signal (you recapped it but you never know).
You said U601 is good (pulled from good chassis?) but I've heard about fake ones.