Missing blue, chassis or tube problem?

kjeffery

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How to tell if Ita a tube or chassis problem? I am missing blue on a wg k4900. As the monitor itself it looks good, nice and bright and red and green is nice and bright . I can see a very very very faint bit of blue but adjustIng the pots does nothing. Any ideas
 
same here i would check the transistors first then make sure your pots aren't dirty.
if you have access to a rejuvenater i would check out the tube to be sure.

Peace
Buffett
 
A good way to make sure it's not the tube is to switch the wires of the bad colour with a known good one, so if you switch the blue wire with red and your blue problem becomes a red problem the tube is good and its a board problem.
 
With what I've learned of monitors, I'll echo the transistors. There are 3 identical color circuits on the chassis. There should be 3 transistors. Swap one of the good colors to the bad color and vise versa. If its one of the transistors, your problem will move to the color you swapped it for.
 
With what I've learned of monitors, I'll echo the transistors. There are 3 identical color circuits on the chassis. There should be 3 transistors. Swap one of the good colors to the bad color and vise versa. If its one of the transistors, your problem will move to the color you swapped it for.
Are those on the chassis or kneck board
 
you can short out the pins one at a time on the neck board,KB for blue, KG for green and kR for red, use an alligator clip hook on side to the frame of the monitor and use the other on the pins one at a time. that will tell you if tube and the color is working since they will go full blast when shorted.
 
both.

3 on the neck and 2 sets of 3 on the chassis. they all control the color processing.

Q401-403 on the neck.
and
q203-208 on the chassis.

Peace
Buffett
 
both.

3 on the neck and 2 sets of 3 on the chassis. they all control the color processing.

Q401-403 on the neck.
and
q203-208 on the chassis.

Peace
Buffett

Kool , I'll try that, I have another 4900 chassis with a hole under the flyback, I'll take parts off it and see what I can come up with
 
that's good.

dont give up on the tube yet.

find someone local with a rejuvenater and see if you can fix the blue in the tube.

that way you will have a spare and or one for another game.

Peace
Buffett
 
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