First let me say that this set is a 318 pound beast! My uncle and I saved it from uncertain doom at the school warehouse recycle area. I have a good friend that works there And it's caught my eye a few times on my way to work. I have an 88 Chevy silver ado long bed extended can 4x4 that this puppy actually weighted it down. Anyway it works to say the least and surprisingly given the reliability of this model with its failing microprocessor that drives startup circuits. The CRT was a bit dim. A little outta focus and a hint red. So I popped open the service menu and tweaked it some to brighten it up. It produces a decent pic now. I had to use tilt correction at -7 maxed out to level the raster. The yoke probably needs a touch up but since I don't have to open it and remove a thousand screWs is all the better. Anyway I cranked up sub pic controls and drives to almost max. Factory is like a bit under half. But the pic was so so washed out. It looks great now but as like my other 40xbr800 I had a few years ago I did not have to fuss with the controls. My question is (and I should now this duh) how much of a strain does this put on the CRT? Not going to be a daily watcher. I know grid voltages go up with drive values increasing but does this really matter? I know the CRT is tired anyway. And being a 40" the geometry is not perfect but corrected as much as I can including focus touched up.

Anyone that knows these 40" trinitron crt's have any thought into the lifespan of them? It would appear after owning two KV-40XBR800's and a 36" version of this set it seems that they tend to loose focus and brightness over time. And when powered up cold they flicker between red and blue for the first 5 seconds or so. It would appear that the design of these beasts without a schematic looks to be 36" CRT guns and fly back ramped up to drive the 40" aperture. Anyone wanna chime in?

Oh yeah and with respect to red lettering on the screen in dark backgrounds. The red bleeds. Both of these do it.

I have one, and the tube seems to be grouchy when cold, but I don't see the bleeding of red. Sadly, I see most of the Sony WEGA tubes getting a little soft by now. I'm pretty sure that the circuitry and guns are indeed the same on 36 & 40 models. I've driven a 36" tube with a 40" chassis I wanted to check out.

Charles

Thanks for the info Charles, it seems that it's possible that the blanking circuit might need to give the CRT more time before supplying the image. The CRT's are indeed big and when there is a predomantly white screen with text the raster gets dimmer.
On the oterhand my KV-3000R displays excellent whites and no differences in dimming (grid) of the raster when whites with text or just a white background is displayed. Also with regards to focus, it never gets sharp. It's decent but not perfect.
It seems that this set from the factory is being pushed to its limits to drive the CRT.
But dont get me wrong, the picture is nice, and not complaining (especially free).
It's be cool if this set had an hour meter so I can see how much torture it's had.lol

On the oterhand my KV-3000R displays excellent whites and no differences in dimming (grid) of the raster when whites with text or just a white background is displayed. Also with regards to focus, it never gets sharp. It's decent but not perfect.
It seems that this set from the factory is being pushed to its limits to drive the CRT.


You're comparing a '49 Buick Limited to a '92 Hyundai :D

Charles

Lol yeah you're right. I'll stop complaining now. I'm just glad I have this set to complement my Sony collection. Consisting of a KV-9PT1, KV-1220U, KV-13TR28, KV-1917, KV-27FS12, KV-3000R and this beast. At least in the collection I have 3 engineering marvels.

Funny thing is the KV-27FS12 has no control for digital convergence and no controls inside and looks miserable.

Oh I just reread my post above yours. The 3000R's focus is razor sharp. I was referring to the 40"s focus around the edges. Way off no matter where you adjust it.

If I may ask, what is 'miserable' about the 27FS12?

I've seen the FS13, and it seems to have a nice Trinitron image, especially if driven through component. Very clear and bright.

Probably a poor choice of words on my part,
what I meant was the convergence on the left and right are out and the bottom left corner is the worst with r,g,abd blue bleeding all over. There is virtually no way to correct it as I have tried. Have a friend with the same TV. Although not as bad it's still there. Not too sure why this model has such poor convergence, but yes, it is a Trinitron, nice, bright and focus is good. Just not one that seems to be quality engineered in the CRT field.. Who knows, it could be a poor quality yoke for all I know.

If I may ask, what is 'miserable' about the 27FS12?

I've seen the FS13, and it seems to have a nice Trinitron image, especially if driven through component. Very clear and bright.

Lol yeah you're right. I'll stop complaining now. I'm just glad I have this set to complement my Sony collection. Consisting of a KV-9PT1, KV-1220U, KV-13TR28, KV-1917, KV-27FS12, KV-3000R and this beast. At least in the collection I have 3 engineering marvels.

Funny thing is the KV-27FS12 has no control for digital convergence and no controls inside and looks miserable.

On non delta-gun CRT sets that are too old to have menu based convergence correction the convergence adjustments are a set of rings on the neck of the CRT that resemble the purity rings(the purity rings are usually in the same cluster and are hard to tell apart). There are good instructions on the net for preforming purity and convergence adjustments on sets like yours.

Also, edge convergence can be slightly adjusted by adding/moving the deflection yoke wedges in or out or putting them in a new spot. I've been able to fix the corners on a few Sonys this way. Tape 'em down if you find a good spot, Sonys like to spit them out, I've found several just laying on the chassis over the years. LOL

Yeppers you guys are spot on about those. I've done both to this set and others. And I have worked on countless Sonys that spit the wedges out. One sure sign the yoke fell down is poor convergence and purity along with A vertically bowed and askewed picture. This set along with messing with the convergence ring and wedges on the yoke have been useless. It's as good as its going to get.

Also, edge convergence can be slightly adjusted by adding/moving the deflection yoke wedges in or out or putting them in a new spot. I've been able to fix the corners on a few Sonys this way. Tape 'em down if you find a good spot, Sonys like to spit them out, I've found several just laying on the chassis over the years. LOL

I wonder if someone set it down too hard and bent the aperture grill? Maybe some low power magnets taped to the right spot on the CRT bell would help, I don't like doing that but it works sometimes.

Yeah that's possible. Maybe sometime I'll tear into it and mess with it again. If I give up its no sweat. People are practically giving those sets away now sadly.