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1992 Sony Trinitron Monitor repair

VERAULT

VERAULT

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Connecticut, USA
So I have gotten around to fixing a 1992 Sony trinitron monitor. Its an Applecolor High-Resolution RGB monitor model M1297, I really needed to get this thing working as all my MAC monitors are below 640 X 480 resolution and finding a high res monitor locally has been impossible. I picked this up from a large haul in New Jersey and Although it had only a small crack to the plastic case on top I think it was dropped a few feet. Not enough to cause catastrophic damage of course.

The unit was DOA when I got it so I assumed PSU was faulty. Upon opening it up I found the weight of the flyback broke the PCB (more evidence it was dropped).Message_1605224103869_resized.jpg

I repaired the PCB and ran wires to repair all the broken traces. 20201113_113800_resized.jpg

After which point the monitor came back to life. But it seems the colors are not in sync (again, from the drop apparently)20201119_162454_resized.jpg20201119_162441_resized.jpg

I am not too great with tuning color tubes so How do I get the RCB to realign? From these photos you can see the RGB (actually it looks like CMY Cyan magenta and yellow)

This had been an interesting repair so hopefully I can get it all the way to fixed.20201119_162504_resized.jpg
20201119_162512_resized.jpg
 
Your convergence got a good whack. Given how it's uniform across the face of the tube and your adjustment rings are still set in gunk it's almost like the entire shadow mask has shifted.....
 
It should be "get backable." But you're going to have to muck with the rings. There should be a whole section in the service manual that gives what order you have to do it in. (which is important)

I think generally, you start from ground zero and do a purity setup and then you do the convergence after that. Once you get it as good as the rings and other hardware tweaks will get you, you use convergence strips to tweak the corners. You can make them DIY.

It takes awhile to get the hang of and is somewhat different from set to set, and also it's dangerous as you're near the HV with your hands.
 
Its a Macintosh item so getting a service manual is pretty much impossible and not going to happen unfortunately. So is there rhyme or reason or do I just start spinning the rings till it all makes sense?
 
VERAULT said:
Its a Macintosh item so getting a service manual is pretty much impossible and not going to happen unfortunately. So is there rhyme or reason or do I just start spinning the rings till it all makes sense?
Click to expand...


Sony setups are relatively similar between similar chassis. You can probably find the instructions in a different manual if you dig around for it. From the manuals I've seen, Sony will actually just reprint the same set of convergence instructions for multiple sets anyway. That's not to say that it's guaranteed, but I think it's likely you'll find one that's close enough. Look around for any sony service manual for any monitor of the same time and description. Google "model number" and "service manual."
There will be lots of free manual sites.

It's really too complicated to walk someone through (for me) and is best done with instructions. And yes, there's definitely a way to do it and a way to not do it.

Even if you can't find a similar chassis, just find any Sony computer monitor service manual and use it for a reference and a starting point. Worst comes to worse you can go from there and write down the effect that each ring has and map what you have to the instructions. You may find though that you have extra or missing rings; not all sets have all of them.
 
And of course be careful. You're already inside there, so I'm just assuming you know you could kill yourself if you touch the wrong thing. The high voltage is present on the wires attached to the yoke.
 
No stranger to high voltage here. Even use the rubber high voltage gloves when in tight areas,,, removes all tactile sense unfortunately.
 
Thanks guys, Its about time I start delving into color CRT repair. So even if this is difficult its a good less to learn.
 
I adjusted the convergence rings on a thrashed out VGA monitor year ago and hooo boy it was a pain. IIRC moving one caused caused the other two colors to get out of whack, so it was a lot of little fiddling to get things back in-whack. I didn't have a manual, just farted around through trial and error.
 
Yeah i was afraid of that. Im used to monochrome where you have two rings. This has about 6 i think. I can see one with a magenta spot. And another with a blue spot. I would assume the yellow spotted one is spun around out of sight. If so that leaves one more ring.. Is there a 4th color ring? Or 3 geometry rings.. Would be good to know the nature of.all the rings before i begin.
 
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Thanks for the pdf's Vol.2, it was pretty much the same monitor as I have so the steps were correct. I read it over and watched a few videos and I am happy to report progress20201120_092341_resized.jpg!!

I ended up using (thanks for the document, as well as a couple videos mentioning this) The V. STAT and H. STAT pots 20201120_092521_resized.jpgon the rear to do most of the calibration. I still had to fidget the rings a tiny bit.
As you can see the upper left corner corner is the worst and I cant seem to get it right20201120_092351_resized.jpg The upper right is better20201120_092402_resized.jpg
Again the only damage to the outside plastic case was near the upper left area seen here and as you can see its a tiny crack but this must be where it was dropped.20201120_095636_resized.jpg

Also I am trying to stretch out the geometry on the picture and when I go vertical the screen starts to curl (especially the upper left corner..) which leaves big black bars on the top and bottom. You can see the white horizontal lines when its curling the image 20201120_092500_resized.jpg


One last thing thats bugging me.. Maybe its an inherent MAC issue I dont know. The monitor doesn't always seem to display the image when my a mac is turned on. I know the machine is booting but the monitor doesn't display the image, I have to swap cables between an lcd monitor with one of those VGA to db15 pin adapters with switches. I am also trying two db 15 video cables.. the older (from an apple IIgs) doesn't have all the pins.. Both work but again, the image just doesn't always come on the screen. I have to mess around swapping cables or trying things. Does the monitor wait for some signal from the mac rather than just display video all the time?
 
Like vol.2 said, to get the convergence bang-on in the corners you will need to make and apply "convergence strips" . It looks like you've done a good job with the rings and should be happy with that.

Macs do use some type of sense pins in the connector to determine output resolution, but I don't know any details on it.

If the image is curling you have reached the end of your adjustment range. It is what it is
 
I realize there is plenty of fine tuning to go, and I will touch upon this again in the future but for now its usable and I am going to button it up.
 
The yoke might have moved when it got whacked. If it moved in-and-out, that could change the size of the raster and also effected the convergence. If you're up against it, it might be a matter of moving the whole yoke.

Unfortunately, that also means re-doing the manual convergence.

If it's good enough then just leave it.
 
Hmm. Hard to say then. With something of that age, you are dealing with a mixture of the obvious damage and worn components. It's possible that the size is due to drifting values in the vertical output stage or a marginal vertical output IC. Or you could have low voltage on a supply or something.

Can't help with the Mac-specific monitor identification issue. I wasn't ever a Mac user, so I don't know the tricks and oddities.
 
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