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I have a late 80's 46" Zenith RPTV which I tried to 'improve' convergence on. Of course, without proper directions, I made it worse. The TV is quite old, but due to my improper adjustments, it has caused my girlfriend to want to purchase a new one, which I don't want to do right now.
I am looking for a reference book, website or technical document which describes what order, test patterns and instrument values would help me to make the convergence acceptable for a year or two, assuming my CRT's are still fine, of course. I want a FPTV for my next house and don't want to invest now.
My level of competence is such that I often start-up hydraulic and electrical systems of 660V, so I understand HV safety, even though the panel containing the trim pots at the front does not require access to the HV section of the TV. I have the Avia test disk, which has many test patterns and feel that with proper instruction, I can improve the convergence to an acceptable level. I have ready access to a true RMS DVM, oscilloscope, signal generator and various FFT/spectrum analysis/DatAq equipment.
I would appreciate any references someone could provide to make the best of this situation. Book names, websites, advice or any other resource would be appreciated.
Sandy.
I have a late 80's 46" Zenith RPTV which I tried to 'improve' convergence on. Of course, without proper directions, I made it worse. The TV is quite old, but due to my improper adjustments, it has caused my girlfriend to want to purchase a new one, which I don't want to do right now.
I am looking for a reference book, website or technical document which describes what order, test patterns and instrument values would help me to make the convergence acceptable for a year or two, assuming my CRT's are still fine, of course. I want a FPTV for my next house and don't want to invest now.
My level of competence is such that I often start-up hydraulic and electrical systems of 660V, so I understand HV safety, even though the panel containing the trim pots at the front does not require access to the HV section of the TV. I have the Avia test disk, which has many test patterns and feel that with proper instruction, I can improve the convergence to an acceptable level. I have ready access to a true RMS DVM, oscilloscope, signal generator and various FFT/spectrum analysis/DatAq equipment.
I would appreciate any references someone could provide to make the best of this situation. Book names, websites, advice or any other resource would be appreciated.
Sandy.
Mmmm... What's the PJ in the guts, a 3 gun CRT? If so, you might want to check it to see if it's got a plate on it and search for that on the web.
3 guns are intimidating, but if you enjoy farting around and figuring out stuff they can be done pretty easy.
You also might want to try setting up a mirror so you can see the adjustment results real time, instead of making an adjustment, running around to the front, making an adjustment, running around to the front... Or worse, using a helper (like your girlfriend, who might not be much help, especially if she really wants a new TV, lol).
Good luck
Dave
3 guns are intimidating, but if you enjoy farting around and figuring out stuff they can be done pretty easy.
You also might want to try setting up a mirror so you can see the adjustment results real time, instead of making an adjustment, running around to the front, making an adjustment, running around to the front... Or worse, using a helper (like your girlfriend, who might not be much help, especially if she really wants a new TV, lol).
Good luck
Dave
This is a hurting solution, but there are TV repair shops all over the place that fix convergence problems on rptv's all the time.
Not exactly a good solution if you are looking for the satisfaction factor, but still a viable alternative.
Not exactly a good solution if you are looking for the satisfaction factor, but still a viable alternative.
sandy_H
just remeber sandy if it went out u can get it back just a matter of getting those manuals and specs, u certainly got the right gear and the right mind
Good luck
Trev
just remeber sandy if it went out u can get it back just a matter of getting those manuals and specs, u certainly got the right gear and the right mind
Good luck
Trev
sandy_H
hey sandy try asking around in this forum they have rptv in here
http://www.hometheaterforum.com/htforum/index.php
trev
hey sandy try asking around in this forum they have rptv in here
http://www.hometheaterforum.com/htforum/index.php
trev
ace3000
please take a look at my new thread"my first video projector design"
and tell me what you think about it
please take a look at my new thread"my first video projector design"
and tell me what you think about it
Pictures on my site
Thanks for the responses. Sorry it took so long to come back, but I wanted to give more info, incase it is of value.
I put a couple of pictures up at www.tshouston.net ,audio button, TV problems button to give an idea of the specific problem and the TV arrangement.
If anybody knows an economical source for the service manual information or convergence methodology, I would appreciate it.
Take it easy!
Sandy.
Thanks for the responses. Sorry it took so long to come back, but I wanted to give more info, incase it is of value.
I put a couple of pictures up at www.tshouston.net ,audio button, TV problems button to give an idea of the specific problem and the TV arrangement.
If anybody knows an economical source for the service manual information or convergence methodology, I would appreciate it.
Take it easy!
Sandy.
Zen and the art of CRT convergence.
A Bridgeport Mill! Man, I wish you were my neighbor.
Are you going to add CNC to it?
Neat looking projector, like many classics, it must have once been state of the art.
I don’t know that I can walk you through setup and convergence but I can tell you a bit about the process. Please however don’t view these as instructions.
· Being that your machine is quite old and the tubes are likely faded, I'm curious if you are observing any blooming. This would be observed if in bright seems the region around the highlights of one of the primary colors overextends its boundaries and forms a sort of a blob. You’ll recognize it if you have it. It could occur on one of more channels simultaneous. Convergence errors will look like red green or blue ghosts.
If the tubes are blooming the anode voltage, the video drive or both will need to be adjusted and will find this post locked up in Texas. Well beyond the scope of what anyone can tell you in a few forum messages. DON’T TRY IT, VERY DANGERSOUS.
· The next step is to make sure that the beams are centered on the tubes. Simple as it sounds, turn on the cross hatch generator, turn the contrast WAY down and look down the thought of the beast(s). You should observe the phosphor region of the tube lightly glowing with the raster stuck pretty firmly in the middle of it. The image will not quite fill the active region of the phosphors.
· Next come the physical alignment of the tubes. With the contrast still set low, and looking into each tube the electric focus is adjusted. Care should be taken hear as too much focus will generate X-rays and damn were back in Texas.
· With the brightness restored, we first adjust the mechanical focus and static position of each of the tubes. Physically cover the red and blue tubes and adjust the green. Uncover the red tube and adjust red to match green. After red is done, cover green and uncover blue, adjust blue to match red.
· Next comes a similar process for dynamic centering and size. Start with matching red to green and then match blue to red. Always cover the tube faces instead of switching off the colors. This minimizes channel-to-channel interactions from power supply instability.
· After size and centering comes the fun parts there will be some combination of adjustments for skew, pincushion, parabola rotation. For each of the adjustments start with green do the center, adjust red to match green, and then blue to match red. After dong the center match the left, right top and bottom. All of these adjustments are interactive, it will be necessary to do this two or three times to home in on the best adjustment.
There comes a certain Zen ness that comes from staring at pink and purple crosshatch for hours at a time. It is likely to have some latent retinal image of the test pattern for a few hours afterwards. Don’t freak, it goes away.
Well this is a sort of five mile view of what the process is like, it is also completely off the top of my head, hastily composed and likely to have more flaws than just the grammer. Hopefully I don’t get THE BIN for talking about the HV adjustment, please THAT NO ONE SHOULD ATEMPT WITHOUT PROFFSIONAL TRAINING AND SUPERVISION. They are dangerous and potentially lethal. If the electric focus is OK and the there is no blooming, it is however possible to set up all the geometry without messing with the dangerous stuff.
A Bridgeport Mill! Man, I wish you were my neighbor.
Are you going to add CNC to it?
Neat looking projector, like many classics, it must have once been state of the art.
I don’t know that I can walk you through setup and convergence but I can tell you a bit about the process. Please however don’t view these as instructions.
· Being that your machine is quite old and the tubes are likely faded, I'm curious if you are observing any blooming. This would be observed if in bright seems the region around the highlights of one of the primary colors overextends its boundaries and forms a sort of a blob. You’ll recognize it if you have it. It could occur on one of more channels simultaneous. Convergence errors will look like red green or blue ghosts.
If the tubes are blooming the anode voltage, the video drive or both will need to be adjusted and will find this post locked up in Texas. Well beyond the scope of what anyone can tell you in a few forum messages. DON’T TRY IT, VERY DANGERSOUS.
· The next step is to make sure that the beams are centered on the tubes. Simple as it sounds, turn on the cross hatch generator, turn the contrast WAY down and look down the thought of the beast(s). You should observe the phosphor region of the tube lightly glowing with the raster stuck pretty firmly in the middle of it. The image will not quite fill the active region of the phosphors.
· Next come the physical alignment of the tubes. With the contrast still set low, and looking into each tube the electric focus is adjusted. Care should be taken hear as too much focus will generate X-rays and damn were back in Texas.
· With the brightness restored, we first adjust the mechanical focus and static position of each of the tubes. Physically cover the red and blue tubes and adjust the green. Uncover the red tube and adjust red to match green. After red is done, cover green and uncover blue, adjust blue to match red.
· Next comes a similar process for dynamic centering and size. Start with matching red to green and then match blue to red. Always cover the tube faces instead of switching off the colors. This minimizes channel-to-channel interactions from power supply instability.
· After size and centering comes the fun parts there will be some combination of adjustments for skew, pincushion, parabola rotation. For each of the adjustments start with green do the center, adjust red to match green, and then blue to match red. After dong the center match the left, right top and bottom. All of these adjustments are interactive, it will be necessary to do this two or three times to home in on the best adjustment.
There comes a certain Zen ness that comes from staring at pink and purple crosshatch for hours at a time. It is likely to have some latent retinal image of the test pattern for a few hours afterwards. Don’t freak, it goes away.
Well this is a sort of five mile view of what the process is like, it is also completely off the top of my head, hastily composed and likely to have more flaws than just the grammer. Hopefully I don’t get THE BIN for talking about the HV adjustment, please THAT NO ONE SHOULD ATEMPT WITHOUT PROFFSIONAL TRAINING AND SUPERVISION. They are dangerous and potentially lethal. If the electric focus is OK and the there is no blooming, it is however possible to set up all the geometry without messing with the dangerous stuff.
Attachments
Getting close!
Da5id4vz, you're right, getting too close to Texas for comfort. Again, I have no desire to play around with the HV section, even though I understand HV work, I don't know TV's enough to be safe. I am only willing to open the front panel where the pots are and even though I can see the CRT's, I have no desire to get near them. All of the mechanical centering etc is over the top for me and I plan to keep it that way. If that seems necessary, I'd call a pro for sure.
"· After size and centering comes the fun parts there will be some combination of adjustments for skew, pincushion, parabola rotation. For each of the adjustments start with green do the center, adjust red to match green, and then blue to match red. After dong the center match the left, right top and bottom. All of these adjustments are interactive, it will be necessary to do this two or three times to home in on the best adjustment."
This is where the problem is, as I am the one who caused it and that's where I did it!! I moved into a new apartment 7 years ago and bought a cheap 5 channel pro-logic system with an unshielded center channel. I put it on the floor in front of the TV and boom, picture is terrible. I immediately jump to the unfounded conclusion that I, knowing nothing at all, should fix the convergence on my own. After totally ruining the picture, I managed to, over 3 or 4 days, tune it back in where it currently is. It took a day to realize that when I moved the speaker the picture got better. It is fine for me, as I usually only watch letterboxed movies and that leaves the problem areas mostly ok. My girlfriend, however, watches mostly black and white movies, which are both full screen and exhibit totally terrible problems, due to the fact that the convergence problems show red, yellow/green or blue on a picture that should have no color at all! In her situation, I agree, it is terrible.
I guess I basically was doing the right thing, just didn't get it perfect back then. I think I'll still try to get a manual of some sort, as there are a few pots that weren't labeled with skew etc, and of course, I remember messing with them too. . . oh, the folly of youth. . .
Thanks for the help. I guess we can gently step away from this topic now, as I am on the right track and nobody needs to get hurt.
Sandy.
Da5id4vz, you're right, getting too close to Texas for comfort. Again, I have no desire to play around with the HV section, even though I understand HV work, I don't know TV's enough to be safe. I am only willing to open the front panel where the pots are and even though I can see the CRT's, I have no desire to get near them. All of the mechanical centering etc is over the top for me and I plan to keep it that way. If that seems necessary, I'd call a pro for sure.
"· After size and centering comes the fun parts there will be some combination of adjustments for skew, pincushion, parabola rotation. For each of the adjustments start with green do the center, adjust red to match green, and then blue to match red. After dong the center match the left, right top and bottom. All of these adjustments are interactive, it will be necessary to do this two or three times to home in on the best adjustment."
This is where the problem is, as I am the one who caused it and that's where I did it!! I moved into a new apartment 7 years ago and bought a cheap 5 channel pro-logic system with an unshielded center channel. I put it on the floor in front of the TV and boom, picture is terrible. I immediately jump to the unfounded conclusion that I, knowing nothing at all, should fix the convergence on my own. After totally ruining the picture, I managed to, over 3 or 4 days, tune it back in where it currently is. It took a day to realize that when I moved the speaker the picture got better. It is fine for me, as I usually only watch letterboxed movies and that leaves the problem areas mostly ok. My girlfriend, however, watches mostly black and white movies, which are both full screen and exhibit totally terrible problems, due to the fact that the convergence problems show red, yellow/green or blue on a picture that should have no color at all! In her situation, I agree, it is terrible.
I guess I basically was doing the right thing, just didn't get it perfect back then. I think I'll still try to get a manual of some sort, as there are a few pots that weren't labeled with skew etc, and of course, I remember messing with them too. . . oh, the folly of youth. . .
Thanks for the help. I guess we can gently step away from this topic now, as I am on the right track and nobody needs to get hurt.
Sandy.
sandy_H
lesson number 1 never put a unsheided speaker next to a crt tube lol come on sandy u should have known better lol but hey **** happends good luck buddy in getting it back, lets just hope the speaker didnt stuff the tubes cos they wont come back to the way they wer if they are magnitised, but u should see the magnitisim if u got purple in the screen.try out that forum i posted eirlier they have rptv in there, if u ask around someone might have a manual
Trev
lesson number 1 never put a unsheided speaker next to a crt tube lol come on sandy u should have known better lol but hey **** happends good luck buddy in getting it back, lets just hope the speaker didnt stuff the tubes cos they wont come back to the way they wer if they are magnitised, but u should see the magnitisim if u got purple in the screen.try out that forum i posted eirlier they have rptv in there, if u ask around someone might have a manual
Trev
I wish I could argue. . .but
Yeah, you're right, it was a bad call. But I was 20 and owned a 46" RPTV for a week and thought B*st B*y was !the! place to shop, so my errors were already building. But I learned, and for the 30-ish minutes that the 3 1/2" driver was in front of my TV probably is not as much of a problem as my 'insight' as far as convergence goes. But, live and learn, as they say. What's worse, trying to converge your own TV or spending $6k on true 'hifi?' I've done both, only to find that I am worse than factory settings and I actually thought half the stuff I own is 'hifi.' The DIY bug is both intoxicating and humbling. It makes you realize what you can and can't do and shows you that your blind faith in chain store 'sales associates' is quite misplaced.
But, as I said. . .live and learn. Thanks for the reference.
Sandy.
Yeah, you're right, it was a bad call. But I was 20 and owned a 46" RPTV for a week and thought B*st B*y was !the! place to shop, so my errors were already building. But I learned, and for the 30-ish minutes that the 3 1/2" driver was in front of my TV probably is not as much of a problem as my 'insight' as far as convergence goes. But, live and learn, as they say. What's worse, trying to converge your own TV or spending $6k on true 'hifi?' I've done both, only to find that I am worse than factory settings and I actually thought half the stuff I own is 'hifi.' The DIY bug is both intoxicating and humbling. It makes you realize what you can and can't do and shows you that your blind faith in chain store 'sales associates' is quite misplaced.
But, as I said. . .live and learn. Thanks for the reference.
Sandy.
deja vu all over again
Is anyone lese getting this? It feels kind of like "Ground hog day.”
I wouldn’t get to worked up about magnetized picture tubes. The tubes likely have a degaussing coil around each one that activates for about 10 seconds each time the set is turned on. Even if the tubes are heavily magnetized clearing them with an external degaussing coil is a simple thing.
Prying my self away from the pictures of your great mill and lathe (is that a South Bend?)I actually looked at the screen shot this time.
Your problem is almost entirely with the blue tube and its not too bad.
Cover the green tube.
Working only on the blue tube, DO NOT ADJUST GREEN OR RED:
Move the horizontal centering of the blue tube to the left. You want to move it about half the distance of what you see the RIGHT side being out. You should now work between the size and linearity to make the offset between red and blue consistent. You should then be able to nudge the centering of back on top of red.
Chase the adjustments in a circle like this for a while, but don’t get too obsessed.
I don’t think you’ll need to adjust pin, trap, or parabola at all.
You should not have to adjust the physical position of the tubes at all.
The horizontal width is some times a choke located in a different location. It will look likes small coil with a cardboard or plastic tube in the center. There will be a small ferric slug in the center that can needs to be adjusted with a plastic or wooden (non metal) didle stick.
From what I saw of this picture you should be able to get back in action in just a few minutes. If we were neighbors Id run right over to give you a hand (specially since you might let me use that awesome milling machine)
-Dave
Is anyone lese getting this? It feels kind of like "Ground hog day.”
I wouldn’t get to worked up about magnetized picture tubes. The tubes likely have a degaussing coil around each one that activates for about 10 seconds each time the set is turned on. Even if the tubes are heavily magnetized clearing them with an external degaussing coil is a simple thing.
Prying my self away from the pictures of your great mill and lathe (is that a South Bend?)I actually looked at the screen shot this time.
Your problem is almost entirely with the blue tube and its not too bad.
Cover the green tube.
Working only on the blue tube, DO NOT ADJUST GREEN OR RED:
Move the horizontal centering of the blue tube to the left. You want to move it about half the distance of what you see the RIGHT side being out. You should now work between the size and linearity to make the offset between red and blue consistent. You should then be able to nudge the centering of back on top of red.
Chase the adjustments in a circle like this for a while, but don’t get too obsessed.
I don’t think you’ll need to adjust pin, trap, or parabola at all.
You should not have to adjust the physical position of the tubes at all.
The horizontal width is some times a choke located in a different location. It will look likes small coil with a cardboard or plastic tube in the center. There will be a small ferric slug in the center that can needs to be adjusted with a plastic or wooden (non metal) didle stick.
From what I saw of this picture you should be able to get back in action in just a few minutes. If we were neighbors Id run right over to give you a hand (specially since you might let me use that awesome milling machine)
-Dave
Attachments
Thanks again
Sounds like a good procedure. I'll give it a shot.
Yep, the Lathe is a South Bend tool room 10" from 1966. The Bridgeport is an M-Head from 1947 with a J-head retrofitted. In the corner (partly visible in the picture of the Bridgeport) is a Grizzly mill/drill. Next to the lathe is a mid-60's tool room grinder. Some pretty neat stuff, but I still have a lot of work to do, setting up and leveling each machine. My phase converters are not here yet, as I can't finish wiring or dry walling and don't want to move the machines into their exact final position. So, I'm just using the Grizzly for now. But, it gets the job done. . .
Thanks again for the help.
Sandy.
Sounds like a good procedure. I'll give it a shot.
Yep, the Lathe is a South Bend tool room 10" from 1966. The Bridgeport is an M-Head from 1947 with a J-head retrofitted. In the corner (partly visible in the picture of the Bridgeport) is a Grizzly mill/drill. Next to the lathe is a mid-60's tool room grinder. Some pretty neat stuff, but I still have a lot of work to do, setting up and leveling each machine. My phase converters are not here yet, as I can't finish wiring or dry walling and don't want to move the machines into their exact final position. So, I'm just using the Grizzly for now. But, it gets the job done. . .
Thanks again for the help.
Sandy.
Thanks for the machine tool update. That will be quite the extreme DIY machine shop.
Phase converters, E-yow! Now your really getting serious. I always figures if I were to come across some big machines I would just put undersized motors on them.
You should be able to make chassis equivalent to the early Wadia's when you get it all set up.
How do you like your Grizzly mill/drill? I’ve spent some time considering that vs. the Jet and Enco equivalents and the Taige mill. I think those will be the biggest machines I'll be able to support in terms of space weight and capital.
Hope the blue channel alignment stuff is at least a little helpful.
-Dave
Phase converters, E-yow! Now your really getting serious. I always figures if I were to come across some big machines I would just put undersized motors on them.
You should be able to make chassis equivalent to the early Wadia's when you get it all set up.
How do you like your Grizzly mill/drill? I’ve spent some time considering that vs. the Jet and Enco equivalents and the Taige mill. I think those will be the biggest machines I'll be able to support in terms of space weight and capital.
Hope the blue channel alignment stuff is at least a little helpful.
-Dave
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