Matsushita (or whatever) no blue...

Check the blue output transistors on the neck board. It's also very possible the tube has a dead blue gun and you could use a rejuvenator to test/fix it. Those Matsushita tubes are known for crapping out. I had one with 2 guns that were dead but my rejuvenator fixed them right up. :)
 
Check the blue output transistors on the neck board. It's also very possible the tube has a dead blue gun and you could use a rejuvenator to test/fix it. Those Matsushita tubes are known for crapping out. I had one with 2 guns that were dead but my rejuvenator fixed them right up. :)

Thats kind of what I was thinking...gotta get one of them rejuvinators!
 
took another peek tonight...looks like there are three orange filements glowing in the neck, are those the guns? if so, would that mean all 3 work? also? i unplugged the game and was watching the monitor when i pulled the plug. right as the power died, red, green AND blue bars briefly lit up the screen....this makes me think this thing can produce blue but for some reason isnt...
 
took another peek tonight...looks like there are three orange filements glowing in the neck, are those the guns? if so, would that mean all 3 work? also? i unplugged the game and was watching the monitor when i pulled the plug. right as the power died, red, green AND blue bars briefly lit up the screen....this makes me think this thing can produce blue but for some reason isnt...

What you see glowing are the heaters for those guns. Just because those are working doesn't mean you'll have blue. There could very well be some crud that's built up on the blue gun that won't let any electrons emit from it. I honestly don't know if seeing blue briefly when you powered down means much at all. I would start with checking out the transistor(s) on the neck board and make sure they are ok especially if you don't own or have access to a crt rejuvenator at the moment. Also look at the blue adjustment pots themselves. If they fail you can see a loss of the color they are associated with.
 
One way to troubleshoot those transistors, failing spare parts, is to simply swap two of them. Swap the blue with, say, green. Now, if you have no green, but now have blue, then the transistor is at fault.

Similarly, if you have a stuck color (haze all over the picture in one color), you can remove the associated drive transistor. If you still have that colored haze after that, then the tube has a shorted gun. If the colored haze goes away, then the transistor was probably shorted (or there was something else wrong further back in the circuit).

-Ian
 
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