KV9200 Issues

[Alex KL-1]

Originally Posted by vol.2

Okay, I thought the current loading was the issue, but I guess you're saying that it's actually a voltage drop on the screen?

The issue I'm having with this is that when I put the 1M pot in the circuit with the other side to ground, it creates a load on the screen supply and the screen dims. I thought it was a current issue, but I guess it would make sense that it's creating an additional resistive divider for the screen potentiometer. There is a lot going on in this circuit, and I'm having trouble visualizing exactly what happens when I put the pot in. It's like this, and the arrow is where I would put the proposed diode in place:



Otherwise, are you saying that I can prevent the voltage drop by using a higher value resistor to supply the Focus Grid, with another one to ground on the other side? I think I mainly need help understanding exactly why the G2 is becoming dim in order to fix it because I don't know how to do the calculations for the resistors if that is so.

If focus adjustment are great at near top, you can add a some Mohms resistor from "cold" wiper from potentiometer to ground (in series with potentiometer), reducing the loading, and making the focus adjusment less coarse.