Thanks very much for the replies so far - and John, thank you for the pointers on how to test AC - i really have very limited knowledge of AC related stuff. Also a string in the centre of the translite does not work

Shansta - i have GI on left and right of machine above the slings that work OK

Nino - as i'm getting 7.9AC at the pins i think (but don't know) that the traces are probably OK

So i removed plugs 120 and 121 and AC between pins 3 and 9 is 7.9v AC (similar for 1 and 7 and 5 and 10)

When i plug in one of the plugs, this drops to 6.9v AC, then plug both in and drops to 6.0 AC (same across all pairs)

Testing voltage at either side of the legs of a non working socket gives 0.25v AC - same as the working ones....

So from this it seems in my mind that problem is less likely to be board related and maybe a shorted bulb in the string - or am i barking up the wrong tree?