Majestic 70 Leatherette restoration

[cluelessgame]

Thanks Kevin! Ended up getting the one off of eBay, hooked it up making sure to get the orientation correct (comparing the SAMs to the diagram provided in the box) and....still no vertical....no raster, that is. There was some deflection though - the solid horizontal line was now flickering wildly in an area about 2 inches wide. The vertical size control had some, yet minuscule effect.

traced every bit of the vertical section over and over, only discovering a lack of voltage on the plate of the 6C4, but no indication as to why. All of the other components were correctly wired, and values were in tolerance. I even substituted a different 6C4 with no change. I began to suspect the b+, but all voltages were reasonable. One interesting phenomena, though, was that if I flip the switch on the back into color mode, the screen goes dark (as it should), and then flip it back, there's about one full vertical sweep, and then back to the 2" wide line of garbage.

Eventually, I decided to try swapping the leads of the secondary coil connections, and that did the trick!
When originally installing it, I noticed that the secondary output wires appeared to be color coded backwards to what the SAMs had. According to the diagram packaged w/ the replacement, the yellow secondary lead came out on the same end as the blue lead on the primary side (as opposed to in the SAMs where the blue and green leads come out the same end. so I wired it yellow to grid, and green to the 1.5M/4700MMF junction. So sure of myself that this was correct I didn't even consider it to be the issue until after weeks of pulling my hair out tracing the B+

So yay, I got that part fixed! Now on to the current issues:

Although I finally have full deflection, it’s not a stable raster. It still flickers erratically, regardless of where the vert. hold is set (does have some effect). After grounding the wipers of the volume and contrast controls (which had apparently come undone) I managed to feed in a signal. The picture produced is able to lock in, so the flickering is from something outside the sweep circuit (I think).

At the moment, I suspect the flickering is somehow caused from the arcing I’m hearing (but can’t locate) in the HV cage…probably should have mentioned it earlier, but since I was getting SOMETHING on the screen, I figured I’d address it after the vertical gets fixed. I’ve cleaned off everything – having to remove the picture tube, focus and yoke mounts in order to take the cage off to get to everything – and discovered that this was a type of set that has a doorknob capacitor with the 1B3 socket screwed on top. Do those typically go bad? Its 500MMF rated for 20000V. There are also two resistors under the socket that are in tolerance, and everything is coated in some sort of black insulating gunk (corona dope?). Its chipped off a little in places, but the arcing doesn’t appear to be coming from there…I’ve pretty much narrowed the sound down to the tube itself…when I push on it the sound changes. I crimped up the contacts in the socket for a tighter fit on the tube pins, but that didn’t help, so now I think it’s coming from inside the base of the tube. I’m waiting on a new one to arrive to verify. Does anyone know if that can cause vertical flickering?

On an unrelated note, it also appears that one side of the audio output transformer is open. SAMs identifies it as Majestic Part No. C-9225-3C / Merit RO-16 / Chicago RO-16, having impedance PRI: 7.8KΩ / SEC: 4.1Ω ||DC res PRI: 450Ω / SEC: 0.7Ω. At the moment I am unable to track any of these down. How crucial are these listed values? I understand other types of transformers are selected based on resonance, but are audio output transformers as sensitive?