[Boatanchors] Viking 1 question

[Jack Antonio]

Working on a Viking I.

80 through 15 are fine, 10 is OK on 28.0,
with a power output of 90W, but at 29.0
was only able to get 50 watts, and the
final plate current not reaching a dip.

Checking with a grid dip meter, the final
tank was only reaching 27.5.

I shorted out 1 turn of the 10 meter
tank coil, and the grid dipper indicated
resonance, and can get 90 watts out at 29.0.
The main roller coil is completely
out, and the main tuning cap is unmeshed.

Question is, has anyone else seen this issue?

Thanks

Jack Antonio WA7DIA/4