Vertical squish

WizardStan

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My Simpsons cabinet had been sitting in storage for a couple years before I finally had a place to put it. Before going into storage it was working more or less fine. Just FYI, I'm mostly newb, but have done enough research to be dangerous, so please forgive me if I say something that doesn't quite make sense.

Powering it up, everything about the game itself seems to work, the game plays and there's sound, but the image is very squashed and distorted, a band about half the screen height in the middle; it's almost like the v-size is twisted all the way down, or up, whichever way "smaller" is; either way, dialling the v-size pot changes nothing. Twisting the v-hold causes it to start rotating, as it do, through this band.
I replaced all the electrolytic capacitors but it hasn't changed. I think it might be "warming up" faster at least; before putting it into storage I used to have to wait a couple minutes before I could actually see the screen but now it's ready under 30 seconds, so I guess replacing the caps was a good thing, assuming I can fix the real problem.
Can anyone suggest a next step? Everything that I read said this was a capacitor issue, but I suspect cap kits are the go-to solution for most problems.
Unfortunately I've got a Zenith K7000, so I'm hoping it's not a flyback issue, but "squashed screen" doesn't seem to be a symptom of bad flyback that I can find. Hopefully not wrong about that.

In addition to this, it's only showing green: the red and blue drive does nothing, and turning the green drive down makes the screen black. This is also a new problem. I've got leads on this but don't really want to investigate too much unless the above can be solved. I say it only to ask, with two big problems (plus the unfortunate fact it's the Zenith K7000), is it worth fixing or should I just buy a whole new tube and chassis?
 
flowcharts are handy for many problems, but won't necessarily help you solve everything

google k7000 flowchart
 
caps aren't going to make any difference to the emissions of the electron guns in the tube. probably some strange coincidence that it warms up faster, unless you're having problems with the solder on R213 on the neckboard (the heater resistor, that should always be reflowed when capping)

your tube just sounds tired, the missing colors could be caused by the guns and not the circuitry on the chassis. I would throw it on a rejuvenator to see what's going on with that.

the white ceramic pots these used were incredibly flimsy and fragile and often break. I'll just take a stab and say you have the stationary pots mounted to the deflection board -- those don't break as commonly as the ones on the remote boards, but they can break. inspect the legs of the V. Size pot closely, you might find a break. same goes with the Red and Blue pots on the neckboard, if you lose either a drive or bias pot, I'm sure the entire color goes. another common issue is the traces or solder pads to the 3 neckboard color transistors will form breaks, disconnecting them from circuit. it might take a few glances to pick up on.

the last thing I have to strongly encourage is checking all the resistors from the vertical IC (the tall heatsink to the right) back over to the voltage regulator (the STR IC mounted to the heatsink wall in the fuse corner). the ceramics, R89 and R101 especially will often get so hot that they halo the solder joints, disconnecting the legs from the circuit. what typically happens is the solder pads burn up, so you'll have to scrape or sand open traces and bridge soldered wire or cap legs into the trace to wrap around and solder to the component legs to fix. don't forget about the tower ceramic on the edge, R103, that's important for power.

the flyback will suffice for now, but like all K7000 flybacks, verify that the plastic case isn't cracking. the cracks will typically develop around the Focus and Screen pots. extreme cases you'll get arcing, or those adjustments will either not work well or at all. (found one of those recently)

good luck
 
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