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ok noise is worked out but the pic was dim. I could make it ok by adj the CRT bias, but should not need that as I was able to get all the guns to show in the setup mode at the lowest setting. I checked the CRT pins and sure enough the cathodes were at least 50v too high (was 240v shb 190v).
So looks like a video out tube. I checked and yes the plate voltage was too high, checking the Cathode and again too high (about 5v not the 2.5 it should have been). So if the video out tube plate is high, and since its directly coupled to the CRT cathodes, that explains the bias problem and the dim pic. I did some resistance checks and it looks like a 100ohm resistor on the bottom of the brightness control may have drifted. Its mount up on the pot on the control panel so I will need to pull it out to check. Hopefully this will resolve the dim pic.
I also have a intermittant blue screen issue, Its like the G2 drops down about 10% all by it self. I will be monitoring the G2 voltage and see if that is whats going on. there are 100k resistors in series with the G2 pots so maybe the blue one is getting intermittant. I will prob just pull the chassis and replace all 3 of them while I am at it. Lastly there was a .1 cap in the grid circuit of the video out coupling the delay line to the grid. I will prob replace it as well since I seem to be having bias issues in that tube.
I will also check the PCB track for any break around that G2 lead but I am just guessing that is what is causing the intermittant drop down of blue in the crt (it like someone just turns it down a few degrees, but its quick not gradual, and it will come back and then do it again). I dont feel like breaking out the cold juice just yet.
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