Help with WG K4600 please...

dbpbandit

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Hey guys, I'm working on a WG K4600 and for some reason I can't seem to get the blue to work.... I know blue works because I grounded the tab on the neck board and the screen turned blue. I've also done a full cap kit, replaced the TR403 and the 12k-2w resistors on the neck board. I also replaced TR204 and TR207 interface board. Still after all of that no blue.... I know the signal from the board is good because I get all three colors on another monitor. I'm not sure where to go from here, any suggestions? Thanks.

-Dave
 
Hey. The monitor forum is one slot further down on the list.

Per the schematics I've got, TR204 and TR207 are for red. TR205 & TR208 are blue.

Check your connector header solder joints, too.

Hey guys, I'm working on a WG K4600 and for some reason I can't seem to get the blue to work.... I know blue works because I grounded the tab on the neck board and the screen turned blue. I've also done a full cap kit, replaced the TR403 and the 12k-2w resistors on the neck board. I also replaced TR204 and TR207 interface board. Still after all of that no blue.... I know the signal from the board is good because I get all three colors on another monitor. I'm not sure where to go from here, any suggestions? Thanks.

-Dave
 
sorry about the wrong forum, thanks for the tips though. just FYI, still no blue....
 
It's pretty easy to trace your blue through.

Check for voltage at the video input to the interface card to verify you have a blue signal there. then check it at the connector on top of the interface card to see if it's coming out. If not, then the problem is on the interface card, probably with one of the two transistors, but possible with a resistor or bad solder joint/trace.

If you have voltage out of the interface card, check for it where it hits the neckboard (to verify wiring) then trace it through the drive transistors to the neck socket. Eventually you should find where it goes missing.

And sometimes colors go away for other reasons (like low 12v to the drive transistor) even though the tube and color signal is good...
 
Do you know what voltage I should expect to see on that blue line? I've used my Ohm meter to trace the blue line but didn't use voltage. I'll give that a try, i'm leaning towards a broken trace at this point since I've pretty much replaced everything else. Where can I check or adjust the voltage at the drive transistor? Or is that what I'm doing in the first part? Thanks...



It's pretty easy to trace your blue through.

Check for voltage at the video input to the interface card to verify you have a blue signal there. then check it at the connector on top of the interface card to see if it's coming out. If not, then the problem is on the interface card, probably with one of the two transistors, but possible with a resistor or bad solder joint/trace.

If you have voltage out of the interface card, check for it where it hits the neckboard (to verify wiring) then trace it through the drive transistors to the neck socket. Eventually you should find where it goes missing.

And sometimes colors go away for other reasons (like low 12v to the drive transistor) even though the tube and color signal is good...
 
It should be the same as the other colors. Put the meter on DC and check the outputs. Hell, if you can, swap one of the wires just to see what you get out of the monitor. You should read about 1.8 VDC coming from the board.
 
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