Last post about my convergence

[TinCanAlley]

The center could use a little touch up, but until I can fix the sides, it's not of great importance.

I started wondering if it's really the blue that's the issue. What if the blue lines are where they're supposed to be and the red and green are off? They seem to interact with each other quite a bit, so if a pot is bad, maybe it's affecting them. Of course I have no way of knowing all this until I get the scope (which I hope to get today). If I get the scope I might be posting the model and some pics and asking for assistance in the settings.

[DaveWM]

small problems at the center get worse at the edges, you need to always check and touch up the center static as you make dynamic adjustments, it does not take much.

That being said the pic you posted shows more that the typical problem with blue.

[TinCanAlley]

Originally Posted by DaveWM

small problems at the center get worse at the edges, you need to always check and touch up the center static as you make dynamic adjustments, it does not take much.

That being said the pic you posted shows more that the typical problem with blue.

I hate trying to do the center convergence. It says to use the dots for it, but the dots are so fuzzy and I expect a pure white dot. I know this isn't possible, but my brain is so picky most of the time it keeps me tweaking it.

[sampson159]

sorry,i forgot it was flat chassis.vertical sets have a smaller coil that moves the blue horizontal centering.

[TinCanAlley]

Originally Posted by sampson159

sorry,i forgot it was flat chassis.vertical sets have a smaller coil that moves the blue horizontal centering.

Here is a pic showing the convergence board and it's plug. I don't know why they bothered with a plug since removing the board would also involve unsoldering the convergence magnet wires. Quick disconnect means nothing if it's only half of the wires involved.

[andy]

...

[TinCanAlley]

Originally Posted by andy

The plug is so that you can easily remove the chassis.

Just in case you don't know, you can remove the convergence panel, and mount it flipped up so that the controls are facing the front of the set for easier access.

Yep, I learned that from my brother. I said to him I thought it was an odd way to mount the controls and he said to flip it up so I can easily adjust while in front of the set. I was so busy wondering why it was mounted there I never thought about it being functional with a little movement.

I get it. You can take the chassis out and work on the bench. I've been flipping her over and it works for me. If I had a business going, I'd sure go the removal route.

[TinCanAlley]

If I jumper the terminals of a convergence pot while it's turned all the way down, there shouldn't be any movement of the lines, right? I would like to do a little testing of the pots on the board and figured I'd jumper the terminals of each pot and see how it responds. Then I'm going to run them through their full range (un-jumpered) and see what kind of range they have on the screen. I'll finish it off by giving the pots another deoxit and fader lube session. Once that's complete I'll try the convergence procedure over again, starting with the center convergence.

Can a pot be accurately measured while still connected? If I connect to the terminals and turn the pot, can I expect a close to accurate readout? If so, should I be looking for a full range (0 to stated ohm value), or do they not zero out fully CCW?

I figure if something is wrong with one of the pots, this should help me determine.

[TinCanAlley]

Okay, did another cleaning with deoxit on all the pots and followed up with Fader Lube to keep them lubricated. I then tested each pot and found one that makes a clicking sound at full CCW and you can also feel it. I checked the resistance across the tabs and it was much lower than the other two pots of the same resistance (120ohm). Two showed that value, but this one only showed about 23ohm. When I connected to the wiper, the other two pots showed 1.2 to 123. This one started at 1.8, when to 27.9 and then started to drop back down to 2.8 and never go anywhere near it's value of 120.

I tracked down an NOS pot and will be purchasing it long with the R/G vertical lines right coil. It is seized in the position left from last adjustment.

I'm attaching pics of the current convergence I've achieved. I think with the pot replaced and the new coil, I should be able to tweak it to make it better. I know perfect is not possible, but I'm pretty close to a convergence I can live with.

Thanks to many here, I'm almost there!

[sampson159]

this is as good as your going to get.all my zeniths look about like this too.turned out very nice.you will never,ever achieve absolute perfect convergence.from about 5-10 feet away,it will look perfect.nice job and now sit back,relax and enjoy this masterpiece!

[sampson159]

not that far off.you can tweak some more and maybe move purity rings very slightly to pull it a little closer.the blue horizontal could move a little more north.i know how this is.you want it perfect.tweak it some more just in those areas but it looks much better than it did and is close enough to enjoy.great progress.set looks good.now some screen shots,please?

[TinCanAlley]

Originally Posted by sampson159

not that far off.you can tweak some more and maybe move purity rings very slightly to pull it a little closer.the blue horizontal could move a little more north.i know how this is.you want it perfect.tweak it some more just in those areas but it looks much better than it did and is close enough to enjoy.great progress.set looks good.now some screen shots,please?

This set only has the two purity rings and am not sure how they can help with convergence. It took me a manual degauss, movement of the rings and yoke to get purity done. Movement of those rings is sure to mess up my purity.

Like I said, I'll wait until the new coil and pot arrive. Until then I'm going to let the convergence be and enjoy what I have for the moment.

[DaveWM]

when you were checking those pots remember some of them may not test right in circuit. You would have to look at the schematic to see if they are isolated.

sometimes you have to comprimise the dynamic convergence, get one side perfect and the other is off a lot, in that case you shoot for the same defect on both sides. How much is normal and how much is a defect in a part can be hard to say. Just remember the idea behind dynamic convergence is to get the lines straight if thats done then it should be pretty close when the static is right on.

there was a post in the early color where a member (6GH8 cowboy IIRC) was having some convergence issues and it was bad caps. If I was have problems I would break out the scope and see if I could see the needed waveforms going to the coils. if they are there then it clear the parts as an issue so just focus on correct setup. Make sure you have all the neck parts in the correct position.

[TinCanAlley]

Originally Posted by DaveWM

when you were checking those pots remember some of them may not test right in circuit. You would have to look at the schematic to see if they are isolated.

sometimes you have to comprimise the dynamic convergence, get one side perfect and the other is off a lot, in that case you shoot for the same defect on both sides. How much is normal and how much is a defect in a part can be hard to say. Just remember the idea behind dynamic convergence is to get the lines straight if thats done then it should be pretty close when the static is right on.

I followed your suggestion and touched up the static as I was doing the dynamic. It helped a little, but most of the improvement came from a second cleaning of the pots. Still, to get the better sides, I had to sacrifice the lower horizontal convergence and especially the lower right corner.

The one pot that tested oddly also had a click that sounded like a wire might have come unwound or something and was clicking as the wiper pushed it over. You could even feel it in your fingers. The coil is a given as it's seized. I'm pretty certain you can't lube the core of them. They seem pretty porous and I'm sure it would ruin the core.

[DaveWM]

smoothly working pots is a def plus. the zenith coils (if they are the plastic ones) can be a real PITA as the plastic crystalizes.