MadMan!
Look at the back of the power switch. The Instant Play function was a diode across the power switch. Clip it out, as it must be shorted. Then the tubes will not be lit, when the switch is in the off position. Probably, just as well.
I used to see those small sets, where the owner would install an in-line cord switch, as it bothered them, that the set was using power all the time. Also, many thought it was a fire hazard.
