Marquee Maintenance & Improvements
(by Mike Parker)

1. LVPS

The most important first check on a Marquee is to ensure your Tube Filament (heater) voltage is correct. A known problem exists with faulty trimpots allowing the voltage to drift too high causing premature failure of the tube. You could have a tube face that looks like a 10 but will be dim because the heater is no good.

This is the trace that needs to be cut:

And this (below) is the 475 Ohm resistor installed. I used a 805 size part rated at 1/8 watts you might want to use a 1206 for more wattage just to play it safe.

Now just install a 20 ohm pot. Remove the filament voltage connector and power up the set to ensure the heater voltage is within range. NOTE: It’ll be a little higher when running with no load.