Thanks for the reply Bob,
On pin 32 with the scope there is "something" but it looks like a small washed out or smudged waveform. By that I mean not a nice crisp square or sine - more like a blurred 'audio' signal would. If I then switch the 'test' switch it gets smaller in amplitude and then seems to dance around a bit...!
One thing I did notice when investigating data from the front panel is that CN11-6 (INH 1) is constantly low and CN11-7 (INH 2) is constantly high. Should these not alternate between low and high...?
Cheers,
Tom