Ok. Just an update on these valves. Talked to Gaspar this morn. Come to find out that a bunch of these valves were fitted with the wrong capacitor causing this problem when used with an extension. Gaspar took 40 off the shelf and put an ext on each one, plugged it in and 6 out of the 40 were bad. Glad to get this solved. Now time to tear into for the second time.