Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: NightWolfx03 on September 14, 2011, 11:39:22 am
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What do I need to check if I seem to have an absence of red. The screen almost looks like it's a big blue / green fire.
I don't have a service manual or schematic for this monitor.
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Actually I think I spotted a shorted transistor / FET on the neck board. I wonder if it ruined anything else or not. It's looks like a drive transistor, it's emitter and base seem to be shorted.
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most common issue when missing colour is the drive transistor
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Swap transistors from one of the other colors to verify.
Have the tube itself checked too....the Zenith ones that came with those like to crappy color guns.
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sometimes the video amp chip goes. if swapping the transistors keeps the image the same, it's probably the LM1203N (IC901)
if swapping the transistors yields a red/blue or red/green image, your transistor is dead.
NOTES:
transistors fail in one of two ways:
SHORTED...
if your image is completely bathed in a color, you have a transistor shorted causing the color to stay on 100%. it is not uncommon for 1 transistor to short out and cause a 2nd to short as well. the heat generated from the shorted transistor overheats the next one closest to it.
OPEN...
if your image is simply lacking a color(s) then you have an open transistor. replace it.
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Yeha I pulled the transistor off the board, I have a dead short between the emitter and the base. waiting for the replacement to come, now I need to get the k7000 finished, there's a newer thread about it.