Philco 50-T1403 with focus problem

[Don Lindsly]

Roger:

You're doing fine.

It is possible that enough current passes through the 5K stacking shunt to power the signal circuits. I would start by removing the 6AQ5 and one end of the 5K. If the picture and sound dissappear, then let's get away from there for a while.

At 110 ma, it seems the TV is not drawing enough current. That is in conflict with the earlier measurement of 52-180 ma through the coil. We're missing something.

Disconnect the focus coil from the TV and put a 150-200 ohm, 5-10 watt, resistor in its place to protect the focus pot.

Apply somewhere around 30-40 volts DC to the focus coil. At 180 ohms, you don't need any protection if you keep the voltage low. Two hundred ma works out to 36 volts. Adjust voltage for best focus and note the current. I suspect it will be somewhat more than 180 ma. If so, we can go from there.

I thought we eliminated the focus coil earlier by substitution. Did we?

Don