Magnavox Astro Sonic Magna Color model 1C7606

[Electronic M]

I'd put another tube in and watch it after turn on in a dark room to see if the plates start to turn red if so pull the plug IMMEDIATELY (unless you want to damage the tube). Sometimes tubes loose vacuum (which is why the getther turned white) due to mechanical shock, and other factors like age, so I'd try another tube carefully before digging in. The caps in the H osc. and those between it and the H output grid would cause the output tube to red plate (which is another thing that may have brought it down to air) as would a dead osc. tube.