I can only guess that it’s some sort of problem with the power supply to the blue crt,

brrazap;.....

1st up;...Have you looked in your ITC222 Field Service Guide for a troubleshooting section ???
2nd;....When the blue goes off , does it suddenly go off OR does it gradually fade away ???
3rd;...How much electronic background do you have ???

Quote

In your set all the CRTs work off the same power supply....We have a supply voltage or a signal problem to the blue crt....
Answer the above questions & I'll see what we can do....OK.......


Later...Ron.M........

Though I haven't been doing that all the time, I don't
want to stress it out further.

Now, the board that connects the the crt's, I don't know the exact name for it.

However, I noticed that they appear to be paralleled through the green board
where the main signal line plugs in. The red & blue boards appear to be identical,
and it occured to me if it would be possible to switch them and see if the red crt
will exhibit the same problem?

However a closer looks shows some differences. A resistor here, a capacitor there, a diode over there..It’s not much, about 95% of a match, but enough to give me pause about switching them.

It's not possible for me to switch the boards.

There's no way the cables will reach the sockets on the boards except for the original configuration. :-(

I clicked on the FAQ/Rules and I either get an insulting "Permission Denied! You are not authorized to view this page." or the page I'm looking for does not exist.

This is rather frustrating. I guess I must have pissed someone off.

Ohhhhhh, I see where you're going. It doesn't actually matter what board goes on what crt. I'll give it a shot later today.

Still, I can't think of any reason why the FAQ page would be denied to anyone, especially a newb.

About once a year I'll pull the crt boards off, take a thin strip of 320 grit sandpaper, and VERY gently sand the surface of the contact pins on the crt's. Over time the contact pins will get a buildup, or patina, of junk on them that degrades the signal flow and picture quality. For the female socket I use a specially modified pin. Taking great care to keep everything clean. It may seem a bit much but taking the time for a little maintenance and cleaning goes a long way.

The tv won't even power up with only two boards connected.

Ok Ron, let's see if I can make a little more sense with this.

The video input line displayed CMP1 in dull green, I called up the menu and and could see it but it wasn't very bright. I tried adjusting the green screen control, turning it up slowly and the green got a little brighter and I could see a green light coming from the lens but nowhere near as bright as it should be.

Whaddaya know, the blue and red crt's powered up, screen came up with no green as expected.

Just out of curiosity I pulled just the green crt board off and turn the tv on. Whaddaya know, the blue and red crt's powered up, screen came up with no green as expected..

Whaddaya know, the blue and red crt's powered up, screen came up with no green as expected. I shut it off plugged the board back in, turned it on and all three powered up and everything was fine with the picture <<<<<<.....
And then he wrote;=>...""The video input line displayed CMP1 in dull green, I called up the menu and and could see it but it wasn't very bright.""

I did warn you about my terminology, as well as my writing.

brrazap;....

It appears that you may have either a bad blue CRT board or bad connections on the board....
Lets try the easy way first....
Since you told me that you can solder very well , here goes....
Your best way to do this is to remove the blue board by disconnecting all the wiring that goes to it & take it out of the set....
If you can't fully remove it , find a way to stabilize the board while you resolder the connections....
Check all the connections for a cracked circle around the connection...Especially the CRT socket....
If you have any doubts about whether or not it's good , solder it anyway...Better safe than sorry....
You have what appears to be a 16 pin IC on that board...Use care if/when you solder those pins....
They are very small connections & very close together making it easy to have solder bridges develop & cause short circuits which can cause damage when you turn on the TV....So BE careful !!!


Lert us know the results....


Lateer...Ron.M.........