Are these things I should consider bad

[TinCanAlley]

Originally Posted by zeno

Service switch kills vertical also kills video & gives the 3 video outs a constant voltage. On this chassis it also adds a crude blanking pulse.

So is the horizontal still there when in setup? Reason I ask is that the bars go away.

Also, don't remember if I checked the voltages on the G2s and G1s when in setup mode. Maybe that is a next move.

[DaveWM]

the bars go away cause the vert is collapsed.

[jr_tech]

Another *very* long shot, but I gotta ask... Is the external dag coating on the CRT ok and properly grounded? Any shielding around the CRT or Yoke that is not properly grounded?

jr

[TinCanAlley]

Originally Posted by jr_tech

Another *very* long shot, but I gotta ask... Is the external dag coating on the CRT ok and properly grounded? Any shielding around the CRT or Yoke that is not properly grounded?

jr

Okay, I don't know about the coating other than there is a small scratch from where the metal shroud around it must have touched it at one point. The metal shroud has a ground from chassis to it and two from the CRT socket connected to it. How do I go about checking for proper CRT grounding?

[jr_tech]

Originally Posted by TinCanAlley

Okay, I don't know about the coating other than there is a small scratch from where the metal shroud around it must have touched it at one point. The metal shroud has a ground from chassis to it and two from the CRT socket connected to it. How do I go about checking for proper CRT grounding?

So is there any connection between the shroud and the dag coating? It sounds as if the shroud and I'm guessing perhaps spark-gaps at the CRT socket are grounded to the chassis. Might want to ohm check the ground connection to make sure.

jr

[old_tv_nut]

You should not need to spend much time on the dag connections. The dag appears intact, as do all the wires. Just look for obvious mechanical problems, and wiggle the connections a bit to see if the problem you are trying to fix shows intermittent effects.

[jr_tech]

Originally Posted by old_tv_nut

The dag appears intact

I must be missing something... I don't see any external dag on the tube... is there just a little area of dag on the lower part of the tube where the grounding strap wraps under?

jr

[TinCanAlley]

Originally Posted by jr_tech

I must be missing something... I don't see any external dag on the tube... is there just a little area of dag on the lower part of the tube where the grounding strap wraps under?

jr

Here's a pic from when I first got her and hadn't been cleaned yet. This metal shield goes all around the back side of the CRT. It had ground straps from the CRT socket and chassis on it.

[jr_tech]

So what area of the tube does the external dag cover... I am still not sure that I see it. Note the highly visible pattern here where the external dag can be clearly seen *almost* to the yoke: http://upload.wikimedia.org/wikipedi...17px-Crt14.jpg
jr

[TinCanAlley]

Originally Posted by jr_tech

So what area of the tube does the external dag cover... I am still not sure that I see it. Note the highly visible pattern here where the external dag can be clearly seen *almost* to the yoke: http://upload.wikimedia.org/wikipedi...17px-Crt14.jpg
jr

In the picture you'll see the metal (bronze colored) shield connected with springs and other screw type adjusters/fasteners (you can see a long screw that is used to pull the sections together for a tighter fit). That's the part that in contact with the painted on DAG of the CRT and then connected to the chassis via a yellow ground connector.

[Electronic M]

The CRT shields on Zeniths of that era almost completely hide the dag. I should know I have at least two Zeniths that use that CRT shield.

[jr_tech]

Originally Posted by Electronic M

The CRT shields on Zeniths of that era almost completely hide the dag.

Good enough! I have never seen one in person and thought that the HV filtering (and ringing suppression) would be really poor if it were missing from a sloppy re-build job or from somebody cleaning all that "dirty stuff" off of the CRT.

jr

[old_tv_nut]

Originally Posted by Electronic M

The CRT shields on Zeniths of that era almost completely hide the dag. I should know I have at least two Zeniths that use that CRT shield.

thanks for this comment - made me look again, and I now see that apparently the picture shows the internal dag (?). If the external only is underneath the shield, then it is probably OK because none of the external components, labels, etc. are disturbed.

I still think the dag is a wild goose chase for anything having to do with the jail bars (isn't that the one thing we are trying to fix here?).

Need to stop shot-gunning and try to follow clues - there is a jail bar pattern in at least some of the CRT leads, and there are questions as to why some of the waveforms are fat (high frequency or low frequency superimposed?). Should be chasing down if those scope waveforms are valid and going from there.

[TinCanAlley]

Originally Posted by old_tv_nut

thanks for this comment - made me look again, and I now see that apparently the picture shows the internal dag (?). If the external only is underneath the shield, then it is probably OK because none of the external components, labels, etc. are disturbed.

I still think the dag is a wild goose chase for anything having to do with the jail bars (isn't that the one thing we are trying to fix here?).

Need to stop shot-gunning and try to follow clues - there is a jail bar pattern in at least some of the CRT leads, and there are questions as to why some of the waveforms are fat (high frequency or low frequency superimposed?). Should be chasing down if those scope waveforms are valid and going from there.

I'm ready and willing to do any testing you guys come up with. I'm going to disconnect the lead for the setup side of the setup switch to see if there's some kind of issue in the switch. It seems to be a pretty basic open design switch, so I cleaned it with Deoxit. That didn't help as I still have the bars and I still can't get a setup line from the red or green and only a faint line from the blue.

[TinCanAlley]

Never mind. I missed a couple of points of connection, so I'll have to start over. I thought I was able to delete posts, but I don't see how.