[DaveWM]

You need to replace the jumper, its only removed for testing with a current meter.

The diag lines you see I suspect are due to trying to drive the CRT too brightly.

You need to follow this order

1) set the HV up with a HV meter on the CRT anode and the current meter for checking shunt current on the 6bk4, follow the sams procedure, please don't jump around. This wil include not only the shunt current but the cathode current of the horz out tube, again all of this is in the Sams.

2) setup up the drives using the setup switch and again following the procedure, this will include the correct setting of the bias pot or switch (which ever is used).

3) check the grey scale and adjust the bias pots for no tint in the high lights again part of the setup covered.

My "guess" is you are simply driving the CRT too hard (maybe its getting soft).

If for some reason the 1st 3 steps do not work then you may have a circuit problem that should be addressed. Good HV regulation is a must, trying to get a good pic with out it is a waste of time. You also need a good grey scale setup, if the set can not produce a good BW pic then no need to try for a color until that is resolved.