hickok 800 tips

ok thanks that helps alot as I was not pressing the P4 while I turning the selector dial. I don't have any bad tubes yet but I will keep looking.
I don't like that the 800 does not have a noise test like the other Hickok models but I have never used the other models with noise test to know if works well or is accurate way to tell if a tube is noisey. Thanks for your help.

I own one and the shorts light actually glows very brightly when you press P4 test if a short is present. It is worded oddly in the manual, but essentially says that switching the selector dial will cause the light to glow when rotating the dial. I found this to be a normal function to be ignored noting as much in sister model publications and expoerience. You simply cannot ignore the intensity of this light and the wild negative swing on the Gm dial when doing a test. Trust me it is not subtle.