Mark I took a look at the shunt pot and found it a little erratic so I took it out and gave it a clean inside and now it’s good. I ran the Diode/Rectifier test again and on change, the needle jumps hard right (with no tube inserted) I also saw that when I turn the selector to position F (600) the needle wants to go hard left and when reversing the meter you can see that it travels as hard as the Diode/Rectifier test. I am stumped at what it can be, I have been trying to trace cables with the schematics but without cutting all the ties it is impossible. Plus I am afraid to do that in case I do more damage.