Monitor Help Needed. Any gurus out there?

[KevinO]

I've got this 1084 that has been plaguing me for months. First I replaced a bad power switch, then a bad audio IC, then a few capacitors to get rid of the lines waving through the screen. I figured I was good to go, but then I had this:



The picture doesn't do a good job of explaining. First, the upper right corner isn't straight. The line goes up on the top right and also bulges out on the side. Then the color convergence is off just in that corner. I tried moving the yoke around, and it helped a little. Pulling the rubber stops out and moving the yoke closer to the tube improved the convergence but not the "warp" at the corner.

I tried an old trick we used to use when I fixed terminals. In those days, there were little square magnets around the yoke, and you would rotate those to get the lines straight. I tried one of these, and while it helped straigten the upper right corner, the red-blue convergence gets worse.

I have not messed with the convergence rings yet, because you're supposed to adjust that for good convergence in the center, which we have. It IS better than when I started. The picture shows AFTER my adjustments. Anyone else have ideas of how to dial it in better?

 

[KevinO]

Well, the "Mess with it long enough and you'll break it" rule still applies. Now I've got crazy colors in one bottom corner, and I haven't even touched any of the convergence rings. Now I need a degaussing coil, but I don't have one. Don't tell anyone, but I tried my magnetic bulk tape eraser...to no avail.

 

[Chuck(G)]

You have a bulk tape eraser? (looks like a hand mixer without the beaters?) That should be good to degauss just about anything--just activate it close to the screen and move it further away, moving the eraser in a large circular pattern.

So how did you get to the ugly corner colors?

 

[KevinO]

Yeah, just like a hand mixer. I used it exactly like you described. You let go of the switch when you're about 5 feet away.

Dunno where the ugly splotch came from. I suppose manhandling the yoke around or using magnets must have done it. I've read that sometimes even moving a TV to a different orientation can cause the screen to do this, so I'm not entirely surprised.

 

[KevinO]

As is the case with many of my projects, it's gone over months (and sometimes years), but I wanted to share that I finally fixed the splotchy colors! In my efforts to fix the distortion in the upper right corner, I had moved the yoke in closer, and I finally moved it back. Moved it more or less back to what was probably the original position, and although I still have some bending in the upper right corner, the crazy colors disappeared. And I still didn't have to mess with the convergence rings. I'm going to just leave it the heck alone!

 

[dabone]

I've got 2 monitors that need a power switch. Where did you find one for yours?

Later,
dabone

 

[patscc]

Just a general note, if you don't have a degaussing coil, keep an eye out for any curb-side TV's. They all have one around the CRT, and usually they're wired in via a thermistor or something similar that you can either clip off or unsolder, should you want to; presto, instant degaussing coil. Not pretty, but works just fine.
patscc

 

[KevinO]

I've got 2 monitors that need a power switch. Where did you find one for yours?

Later,
dabone

I bought 4 of them from Jameco. Part number 174238. These are nearly perfect, and I have used them in two different monitors. On one, I had to shave off about 1/16" off the end of the plunger. Also, the originals have "wood screws" that screw into the plastic. The new ones have metal ears and require a small machine screw. Working on PCs, I have these in abundance. They're one of the common sizes.

http://www.jameco.com/webapp/wcs/st...Id=10001&ddkey=http:StoreCatalogDrillDownView

 

[KevinO]

Just a general note, if you don't have a degaussing coil, keep an eye out for any curb-side TV's. They all have one around the CRT, and usually they're wired in via a thermistor or something similar that you can either clip off or unsolder, should you want to; presto, instant degaussing coil. Not pretty, but works just fine.
patscc

Yeah, I saw that somewhere too, but I've never tried it. Thanks.

 

[patscc]

Works like a charm. The thermistor automatically reduces current to the coil, but if one doesn't want to fuss with that, just slowly move the coil back and forth across the CRT, and slowly back it away.
It's worth checking whatever you're trying to degauss in the first place if there's already a coil built in, if so, and there's still discoloration, either the thermistor circuit is shot, or there's another problem.
patscc