I just needed a bit of a refresher on PLLs from my notes of 40 years ago; I'd forgotten quite a lot.
Anyway, there's no access to any test points on A10A7 from the top side but I note on the opposite side where the PCB traces are visible there were a couple of tiny holes in the perspex sheet which I assume are there to permit one to stick the point of a probe through (with difficulty) and they were marked something like 500khz ref and 500khz divided so I assume on my model that's where one is supposed to measure the signals. However, on probing, both were intermittent and grossly distorted square waves so something's obviously not right there.
I was really struggling with the PDF schematic on my computer so printed out the A10 20/30 block diagram from the manual which makes things a lot clearer not having to flip from one page to another and lose where all the connections are going to and from!
Jinxie