Convergence ?

[old_coot88]

Has the convergence diode pack ever been replaced?

[Yamamaya42]

Originally Posted by old_coot88

Has the convergence diode pack ever been replaced?

Yop, with a NOS selenium rectifier pack

I never did like the sliding type of holders they used for the static magnets, always seemed problematic, you look at them funny they shift!

It's only slightly off gotta look close to see it, but not as good as it used to be.

my other roundie, the GE CTC-15 clone which is rarely used, is still pretty good, so I'm guessing it has to do with once a week use for an hour or 2 and thermal cycling, over the last year and a half.

[Yamamaya42]

I replaced the Vert tube June 22 with a NOS 6GF7A, that was the last time it was converged.

Perhaps the tube has broken in a bit, and things are slightly off now, who knows.
blue static is very slightly above R/G, and R/G are not as good as they could be.


R/G vert top is also a bit off again :/

[old_tv_nut]

Originally Posted by Yamamaya42

I replaced the Vert tube June 22 with a NOS 6GF7A, that was the last time it was converged.

Perhaps the tube has broken in a bit, and things are slightly off now, who knows.
blue static is very slightly above R/G, and R/G are not as good as they could be.


R/G vert top is also a bit off again :/

Convergence can be affected by vertical height and linearity. I would check those first before touching the convergence controls.

[Yamamaya42]

Originally Posted by old_tv_nut

Convergence can be affected by vertical height and linearity. I would check those first before touching the convergence controls.

That would no doubt be the first step I check, but i co have no doubt i will have to touch things up again.

[reeferman]

Age brings inevitable change that can't be reversed.
Accept it and enjoy the picture.

[Yamamaya42]

Originally Posted by reeferman

Age brings inevitable change that can't be reversed.
Accept it and enjoy the picture.

If i have to spend a few hours with my face to the screen every year and a half to 2 years to keep it in peak convergence, i really don't mind it!

https://i.imgur.com/8wFk2gc.jpg

I know what the set can do!

[jr_tech]

Originally Posted by Yamamaya42

If i have to spend a few hours with my face to the screen every year and a half to 2 years to keep it in peak convergence, i really don't mind it!

About how many hours of actual operating time does that represent?

jr

[Yamamaya42]

Originally Posted by jr_tech

About how many hours of actual operating time does that represent?

jr

This set gets occasional weekend use, mostly on Sat ( not every one ), from 30 min to an hour, and periods up to 2 hours or more on Christmas eve, there are of course other brief times that it's on, but those are the regular use it sees.

[TUD1]

I've been fighting the comvergence on my 16X lately too. Some sets converge up nicely, while others fight you every step of the way. My 16X is the latter example. I replaced the recitfier block and it helped, but after 3 hours of going around and around, my back was aching and I got it "good enough."

[Penthode]

Originally Posted by TUD1

I've been fighting the comvergence on my 16X lately too. Some sets converge up nicely, while others fight you every step of the way. My 16X is the latter example. I replaced the recitfier block and it helped, but after 3 hours of going around and around, my back was aching and I got it "good enough."

I have gone thru this as well. Always wondered if it was the geometry of the shadow mask itself? Eg maybe it is slightly warped over time?

[Yamamaya42]

Originally Posted by Penthode

I have gone thru this as well. Always wondered if it was the geometry of the shadow mask itself? Eg maybe it is slightly warped over time?

Mine has always been a fight as well, round and round to try and get it as best as I can, always seems worst on the right side

[old_tv_nut]

Originally Posted by Penthode

I have gone thru this as well. Always wondered if it was the geometry of the shadow mask itself? Eg maybe it is slightly warped over time?

Shadow mask warping would ruin the purity long before affecting convergence. In fact, convergence is supposed to make the beams coincide at the faceplate, not at the shadow mask.

Long term drift most likely is due to circuit components, not only in the convergence circuits but in the horizontal and vertical size and linearity.

Of course, some sets just never will have all four corners optimum at the same time (and if you're really picky, maybe all sets).

[Alex KL-1]

Some time ago, thinkering and playing with my delta gun TV (a "last generation" delta-gun; the only delta in my small collection), I almost created a thread for the convergence issue, but then I found that the TV certainly dropped, and purity is not consistent also.
This affected one side; the left side converges scary unbelievably good, basically textbook perfect, but right side, the G is not || to the R+B (coincides with bad puruty)... this is strange; normaly I see people complaining about R or B not converging to the others... this G lost even don't make sense to the convergence panel adjustment descriptions.
So, I think I can need to live with it, until I found another set.

Or, is worth to try to play a little with it?

PS.: this tube also have another problem, but I think is about the socket: is very inconsistent with focus. But, I dunno why the image is more dim when focus is wrong, go figure... (well, I never worked with delta gun CRT, so I dunno if it is a normal behaviour, or...)

[Electronic M]

Originally Posted by Alex KL-1

Some time ago, thinkering and playing with my delta gun TV (a "last generation" delta-gun; the only delta in my small collection), I almost created a thread for the convergence issue, but then I found that the TV certainly dropped, and purity is not consistent also.
This affected one side; the left side converges scary unbelievably good, basically textbook perfect, but right side, the G is not || to the R+B (coincides with bad puruty)... this is strange; normaly I see people complaining about R or B not converging to the others... this G lost even don't make sense to the convergence panel adjustment descriptions.
So, I think I can need to live with it, until I found another set.

Or, is worth to try to play a little with it?

PS.: this tube also have another problem, but I think is about the socket: is very inconsistent with focus. But, I dunno why the image is more dim when focus is wrong, go figure... (well, I never worked with delta gun CRT, so I dunno if it is a normal behaviour, or...)

There are things you can do. First thing I would try is using an external service degaussing coil to try and get the impurity to go away, then if it doesn't I would go through the purity adjustments and see if I could adjust it out. (Edge purity is highly dependent on deflection yoke position so doing a full by the book purity may fix it). If that doesn't fix purity maybe try a refrigerator magnet on the bell near the bad spot as a last ditch.

EDIT: to keep from going off topic others mentioned some sets are a pain to converge... I've found 2 things influence that bad convergence board parts (R,C and diodes), and convergence yoke placement and warping. Sometimes the yoke needs to be back or forward ~1/4" from where it's at to either have more range or overshot less, I've also seen some plastic yokes where one set of petals is angularly closer than it should be due to plastic degradation... That's not easy to deal with.
What probably gave me my worst headaches until I realized was a 19" metal cabinet Zenith a respondent to this thread sold me a while ago...I spent a bunch of time troubleshooting the board because of top hat diodes that looked like they'd been soldered in by Ray Charles, then finally realized that the convergence yoke was installed BACKWARDS and the red yoke petal was over the green gun and vice versa....It got really good when I fixed that.