Thank you STC 830! Marcc Brad and Johnny. For the considerable time you have put into this. If I have forgotten anyone thank you also.
I did not get the manual with the unit. The serial no. Is : 2881383. I am glad I am not the only one that has struggled with this tester.
I accept I may well be a sandwich or two short of the full Picnic this unit I find bewildering when I have more time I might have another go at it. Problem was I was trying to repair a B &K model 960 Radio Analyst and wanted to test the two 12AU7'S in it.
My other valve tester is a Hickok 510 this is a beautiful machine unfortunatley it did not cater for the later 9 pin valves . When I was a lot younger and smarter I made up an adaptor for this purpose however I have since lost it and I am not sure I have sufficient patience or enough grey cells left to work it all out again. Apart from the fact it tried to kill me once when the chassis became live it has been brilliant .Cant remember the cause however I fixed it.
Regards Jimb

No worries.
Put the time in because the 6AR7GT is relatively rare, it gave me a bite when I was testing it, and the valve came from a radio for which I was trying to track down the reason for a low high tension voltage (never found it).

When you know the mind is not as good as it was, sometimes it takes something like a bite to really get you thinking so no one else gets caught. If I had in a moment of abstraction grabbed the valve to pull it out of the socket I may not still be here.