These K7400s are drivin' me nuckin futs!

QbertWPC

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...Working on the 7th K7400 so far this month(there's plenty more glaring at me in a box)...

This one is in shutdown,

-HOT was shorted, replaced and hasn't blown since
-Changed C713, C730, C155, and C107
-Swaped IC U701 with known good one
-Flyback was cracked near focus pot, was replaced with new one
-Polypropylene caps in horiz. section checked OK, nearby diodes are good

Still stuck in shutdown, the B+ voltage is around 20vDC
 
Still stuck in shutdown, the B+ voltage is around 20vDC

20, not 120? That's not shutdown, you have power supply problems. K7400 in shutdown with a healthy PS will show 160VDC for B+, and you'd be able to drag it down to 120 with a light bulb.
 
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Yes, 20vDC.

I thought it was in shutdown since I hear the normal ticking sound.

ticking means a blown HOT. Not surprising since you mentioned via PM that the flyback cracked and you sealed it (but should've replaced it)...
 
that reads good....check c117 ...its a 22ufd cap and also c115.....its the big 100ufd cap...these are known to go bad. Next I would test the mosfet (Q101) and also U101 (its the power on chip)
If all of these are working, you should have your B+ atleast up where it belongs.
 
BTW - I just worked on a K7500 that was ticking and was NOT the HOT. The B+ was about 28vdc. Turned out to be a shorted diode at D118. I'll be adding it to my repair logs soon...
 
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