Admiral 17T1: Never Give Up, Never Surrender

[jr_tech]

“-I do have a 15 volt panel meter! I set the needle at 1 volt so I could see negative deflection, checked the grids and cathodes, then reversed the leads and repeated the readings. The readings were perfectly steady: G1 1.5V, G2 zero, K1 zero, K2 4.5V. So, does that mean the vertical sweep voltage is the cause of this issue, and I can ignore the irregularity of the voltages?”

Perhaps... the ac voltage (vertical sweep signal) may be disrupting the measurement of the dc voltage, as your fast response dmms may be sampling the dc voltage as well as the value of the ac signal at the instant(s) the samples are taken.

Or perhaps the dmm is attempting to auto-range to track the varying voltage .

On the other hand, the jumping could be caused by a noisy resistor in the hv circuit (popcorn noise), but it seems that your panel meter would have indicated fluctuations.

Do you have a high voltage probe?

jr