Motorola M7000 Issue

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I've got a Motorola M7000 chassis that powers up and the kneck is glowing, but I've got no display. Turning the brightness up all the way up produces a white background with a raster that is visible so the Hor/Ver seems to be acceptable. Is this more likely to be a blanking circuit issue or a problem in the whole composite video input conversion section? Is there a higher fault rate in one vs. the other?

Thanks,
Greg
 
Atari's The Book has a small troubleshooting section for the monitor I'll attach the no video section. I had the same issue a while ago and I believe it ended being a transistor but can't remember which on. Good luck.
 

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Just for future documentation - Q5 transistor B1E bad - open B-E junction. Replaced with 2N3439 sub and clip on heat sink and my display has returned. Although whoever had this before must have turned every pot on the board trying to see if that would fix it. Vertical size, linearity - everything screwed up. After adjusting things everything seems fine for now. I'm letting it run to see if it fails.
 
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