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TinCanAlley 08-19-2013 04:51 PM

Last post about my convergence
 
1 Attachment(s)
I know there is not such thing as perfect convergence on CRTs, especially older sets, but I need to get closer than I am. I'm used to seeing a little red or blue on edges of images, but they've always been less than an 1/8". What I'm dealing will on the right and left edges are separations of up to a 1/2" and covers 2" on the left side and 6" of the right.

I know it should get better than this. No one would buy a set if the convergence were this bad. Since I've done all the electrolytic caps, could it be a resistor or capacitor on the convergence board?

I'm attaching a pic. Don't pay attention to the bottom lines. Those are lined up now. I had then lined up, but made them that way when tried to get the edges better. The sides are still as messed up, but not the bottom center horizontal lines.

DaveWM 08-19-2013 04:56 PM

http://www.youtube.com/watch?v=2wYn3xLrZj0

again you need a scope to make quick work of this. does the blue horz coil have any effect?

TinCanAlley 08-19-2013 05:06 PM

Quote:

Originally Posted by DaveWM (Post 3079871)
http://www.youtube.com/watch?v=2wYn3xLrZj0

again you need a scope to make quick work of this. does the blue horz coil have any effect?

Nice video. I wish mine was that easy. I've replaced the blue coil and it has the same results as given by the original one before the core cracked.

Since things on the board are pretty interactive, could it be another pot or coil? I know there's one pot that doesn't really cause much movement on the screen. It could be an issue.

I did deoxit all of the pots and treat them with fader lube, but it only made them turn better.

DaveWM 08-19-2013 05:20 PM

other than checking all the parts its hard with out a scope. feel for cold resistors (esp large ones) same with pots (they get warm), lastly the diode pack may be bad.

This is what I try to avoid part replacement to fix a problem, sorry if it sound negative, it just a hard way to fix things.

TinCanAlley 08-19-2013 05:23 PM

Quote:

Originally Posted by DaveWM (Post 3079878)
other than checking all the parts its hard with out a scope. feel for cold resistors (esp large ones) same with pots (they get warm), lastly the diode pack may be bad.

This is what I try to avoid part replacement to fix a problem, sorry if it sound negative, it just a hard way to fix things.

Another reason I need to get my brother and his scope over here. This may seem like a lame question, but how do I know what to set the scope to? The SM doesn't have anything about working on the convergence board.

DaveWM 08-19-2013 05:26 PM

well there is a vert pulse and a Horz pulse so you just setup so you can see them. you bro should know for his scope where those are.

if the blue coil does nothing don't over look the convergence cluster itself, check the coils for continuity where they terminate at the convergence board

TinCanAlley 08-19-2013 05:28 PM

Quote:

Originally Posted by DaveWM (Post 3079881)
well there is a vert pulse and a Horz pulse so you just setup so you can see them. you bro should know for his scope where those are.

if the blue coil does nothing don't over look the convergence cluster itself, check the coils for continuity where they terminate at the convergence board

Think I'll pull the convergence connection so I can put the whole thing on the bench and go over it.

zeno 08-19-2013 05:42 PM

Davewm has you on the right track. All the waveforms are shown on the
conv socket if you got the sams. Convergence probs are
rare, tube zeniths had diode packs go & left blue pots.
your biggest hint is if any controls dont work or
barely work. And dont forget you often have to go back & forth
allot sometimes inc. the middle.
BTW the right is always the hardest.

73 Zeno:smoke:

sampson159 08-19-2013 07:31 PM

the blue is always out slightly on these zeniths but that is way off.does the blue move at all when you adjust it?if not check solder joints.then go to resistors.doubt if it the diode pack is defective but anything can happen.

TinCanAlley 08-19-2013 07:55 PM

The blue coil moves the lines up on the right, but then totally messes up the left side. I can get the left pretty close, but then the blue horizontals at the top of screen are off. The only way to get the top horizontal lines converged is to back off the coil and let the right and left get that far out of whack.

There is one pot that doesn't seem to do much at all. There's barely a difference and I should have noted it and figured out what it was supposed to adjust. I don't remember which one it was and will have to go back and start turning them again.

I was able to check the resistors in circuit and they read at their values. Not sure how to test the diode pack. Don't think it's an easy removal and I doubt it can be tested in place.

I used the ohm setting to check each pot and coil and not were "open". Don't know what else I can check. Gotta get my brother's scope.

TinCanAlley 08-19-2013 08:01 PM

Quote:

Originally Posted by zeno (Post 3079886)
Davewm has you on the right track. All the waveforms are shown on the
conv socket if you got the sams. Convergence probs are
rare, tube zeniths had diode packs go & left blue pots.
your biggest hint is if any controls dont work or
barely work. And dont forget you often have to go back & forth
allot sometimes inc. the middle.
BTW the right is always the hardest.

73 Zeno:smoke:

Well I'll be.... Didn't even notice the convergence is part of the schematics! I really need to pay better attention.

It seems the blue pots are moving things around, but whether they are doing it as designed, that's another story. I know there's one pot that isn't doing much when turned, but I forgot to note it and now have to find it again.

I don't know of any way to test the diode pack.

andy 08-19-2013 08:49 PM

...

TinCanAlley 08-19-2013 09:04 PM

Quote:

Originally Posted by andy (Post 3079919)
There is definitely something wrong if you can't get it any closer than that. It's normal for the opposite sides to interact a LOT. The left control will affect the right almost as much as the left. You have to alternate between them until you reach the best compromise. It's best if you ignore everything except the areas you're adjusting, then make small compromises reduce any major errors. Isn't there a top/bottom blue control on this set?

Well there are two (coil and pot) that work together to move the horizontal blue up and down from center towards the top and bottom of the screen. Then there's another pot that works with the coil just mentioned that adjusts the horizontal lines on the left and right sides of screen. Their interaction has to be going wrong somewhere as the red and green lines meet up on the sides.

The thing is, the compromise I've made is to allow the right and left to look like crap so I can get the center to look good since it's the main viewing area.

DaveWM 08-19-2013 09:13 PM

you have to constantly touch up the static as you adj the dynamic, and I hope you did the purity 1st or you are wasting your time as a purity adj will throw ALL convergence off.

purity
center static
then the order in the sam on dynamic
touch up center as you go.

TinCanAlley 08-19-2013 10:06 PM

Quote:

Originally Posted by DaveWM (Post 3079925)
you have to constantly touch up the static as you adj the dynamic, and I hope you did the purity 1st or you are wasting your time as a purity adj will throw ALL convergence off.

purity
center static
then the order in the sam on dynamic
touch up center as you go.

I did manual degauss using a coil, purity, grayscale, static and then dynamic. Was told that static doesn't need adjusting after being set and only dynamic should be adjusted.

The center of the screen looks just fine, it's the sides that are way off.


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