CurtPalme.com Home Theater Forum

dean cobb · Joined: 19 Sep 2009 Posts: 16 Location: Parma Ohio

blue will not converge bottom two horizontal lines uneven. when I try to make better other areas get worse. I can make the red and green match. Followed zenith service manual no help. Tried numerous times. Also I get blotches on the screen most of the time also. Only running s video at this time. Waiting for rgbhv cable to come in. I am using a zenith pro 895x. thanks

Sparky015 · Posted: Tue Nov 24, 2009 2:42 pm Post subject:

Dean, I found that if the rasters are not centered and mechanically alligned to start, then the electronic convergence has to work that much harder, and you end up with things like this. If you turn contrast down and bring up your patterns, are they centered on the tube face and aligned to the other tubes?

Paul

CIR Engineering · Posted: Tue Nov 24, 2009 2:57 pm Post subject:

Is this rear projection?

It looks like your image is not centered in the raster or is at least too far towards the bottom of the raster. If the set has independent controls for raster centering, and image placement inside the raster, then you will need to use these controls. Often however, rear projection or direct view CRT's do not have these adjustments. If this is the case, you will have to just overscan the unusable part of the image and just push it off the screen so you can't see it anymore.

craigr

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I always thought those squiggles or bends at one edge of an image is the vertical timings not being large enough . I had the same issue and increased the pixels for Total V and they went away.

Athanasios

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Forget about those squiggly lines at the bottom but you do have some convergence issues. This document will show you how your adjustments function. One adjustment may affect another area so you just have to figure out how to correct it afterwards. If you are unable to correct it then you have a blue convergence electronic problem.

I would neutral all the blue convergence settings and start from scratch.

As far as the blotches, I would look into the blue lens and check for fungus. You may have to pull the lens to get a good look.

http://www.curtpalme.com/docs/Zenith880_881_900_ConvergenceControls.jpg

Sparky015 · Posted: Tue Nov 24, 2009 3:44 pm Post subject:

I would just add that you have to do less convergence if your mechanical setup and tube raster setup is done properly, so I would start there and work your way to convergence. It will make your pj more reliable as well, as your electronics won't have to work as hard. I don't have a Zenith, but my two Marquees worked this way.

Paul

CIR Engineering · Posted: Tue Nov 24, 2009 4:54 pm Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Those squiggles are the image falloff before the beam sweeps back to the top. It is normally off the screen. The bottom line of the grid is probably to high, which is what I think he is saying. His main issue is the improper geometry of the grid.

dean cobb · Joined: 19 Sep 2009 Posts: 16 Location: Parma Ohio

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

dean cobb · Joined: 19 Sep 2009 Posts: 16 Location: Parma Ohio

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

dean cobb · Joined: 19 Sep 2009 Posts: 16 Location: Parma Ohio

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

It will depend if your outside the wear area. If your not outside the wear area then try moving the blanking in on that side until it hits the picture edge.