This is called breathing. From the TV days. Some do it worse some pretty good. All this up to quality of the flyback. Really! It's proven.

A story to tell about the breathing:

Back in the day during tail end of CRT days around 2007-9ish, we had repaired many RCA TVs and we used 3 types of flybacks: Original, generic and quality third party flys made by german called HR Diemen and is still in business!

Yes on same model and same chassis (board) we used:
Original, little breathing but acceptable.
Generic, breathed like crazy in time with overall brightness changes (dark and bright back and forth) and irregular widths where bands of dark and light brightness were. Horrible! On top, top and bottom height changed some too.
HR Diemen flyback back to OEM and even better quality.

Second, you might need to rebuild the B+ circuit which is the supply that goes directly to the one pin on flyback then internal winding then back out to the collector of the HOT transistor and goes to emitter of the pincushion & width circuit. More stable the B+ is, more steadier the picture is.

basic tutorial on horizontal circuit:

http://www.broadcaststore.com/pdf/model/79369 … %20-%205080.pdf

Cheers,

pentiumspeed wrote on 2023-01-28, 00:08:

This is called breathing.

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the screen content is brighter). Breathing is influenced by the impedance of the flyback transformer: High brightness pictures put more load on the anode circuit. If that circuit has high impedance, the anode voltage drops. This reduces the speed of the electron beam, and thus the electrons spend more time near the deflection coils and get deflected more.

Blooming is (apparent) loss of focus at bright pixels, without geometry distortion. Blooming is a very typical effect if the picture is very bright. Turning down the overall brightness typically reduces blooming a lot. The primary source of blooming is the CRT itself.

So while breathing is most prominently due to a low-quality flyback transformer, blooming is due to a low-quality or worn-out CRT.

It seems what I meant is breathing. There is no loss of focus in bright areas on either of my CRTs.

mkarcher wrote on 2023-01-28, 22:53:

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the scree […]
Show full quote

pentiumspeed wrote on 2023-01-28, 00:08:

This is called breathing.

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the screen content is brighter). Breathing is influenced by the impedance of the flyback transformer: High brightness pictures put more load on the anode circuit. If that circuit has high impedance, the anode voltage drops. This reduces the speed of the electron beam, and thus the electrons spend more time near the deflection coils and get deflected more.

Blooming is (apparent) loss of focus at bright pixels, without geometry distortion. Blooming is a very typical effect if the picture is very bright. Turning down the overall brightness typically reduces blooming a lot. The primary source of blooming is the CRT itself.

So while breathing is most prominently due to a low-quality flyback transformer, blooming is due to a low-quality or worn-out CRT.

Hello, if it's ok to "hijack" the thread for a question, I have a FD Trinitron that has had over 41.000 hours of usage and the corners were noticeably blurry along with some geometry issues. I fixed the geometry to a very good level through the Service Mode features and then through a mix of adjusting the focus pot and re-tweaking brightness/contrast the corners were much more acceptable, although there are some convergence issues around those areas. With a tube that has had so many hours, is there anything else that can be done regarding the corner focus / convergence? Thanks

andre_6 wrote on 2023-01-30, 18:02:

mkarcher wrote on 2023-01-28, 22:53:

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the scree […]
Show full quote

pentiumspeed wrote on 2023-01-28, 00:08:

This is called breathing.

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the screen content is brighter). Breathing is influenced by the impedance of the flyback transformer: High brightness pictures put more load on the anode circuit. If that circuit has high impedance, the anode voltage drops. This reduces the speed of the electron beam, and thus the electrons spend more time near the deflection coils and get deflected more.

Blooming is (apparent) loss of focus at bright pixels, without geometry distortion. Blooming is a very typical effect if the picture is very bright. Turning down the overall brightness typically reduces blooming a lot. The primary source of blooming is the CRT itself.

So while breathing is most prominently due to a low-quality flyback transformer, blooming is due to a low-quality or worn-out CRT.

Hello, if it's ok to "hijack" the thread for a question, I have a FD Trinitron that has had over 41.000 hours of usage and the corners were noticeably blurry along with some geometry issues. I fixed the geometry to a very good level through the Service Mode features and then through a mix of adjusting the focus pot and re-tweaking brightness/contrast the corners were much more acceptable, although there are some convergence issues around those areas. With a tube that has had so many hours, is there anything else that can be done regarding the corner focus / convergence? Thanks

Nothing you can do much with heavily aged even "Trinitron" is just a branding and I consider Sony sneaky and restrictive. I repair TVs and monitors in past. When heavily aged monitor I knows this is that CRT coarse adjustment magnets placed on the CRT and fine adjustment in the microcontroller cannot fix this due to degraded CRT from age, including the cathodes going soft. This aging affects all CRTs of any quality including low quality ones is really worse.

Sorry about that. Best thing you can do is live with this or find a more fresher quality monitor.

Cheers,

pentiumspeed wrote on 2023-01-30, 20:22:

Nothing you can do much with heavily aged even "Trinitron" is just a branding and I consider Sony sneaky and restrictive. I re […]
Show full quote

andre_6 wrote on 2023-01-30, 18:02:

mkarcher wrote on 2023-01-28, 22:53:

Please don't mix up breathing and blooming. Breathing is a change in picture size (the complete picture gets bigger if the screen content is brighter). Breathing is influenced by the impedance of the flyback transformer: High brightness pictures put more load on the anode circuit. If that circuit has high impedance, the anode voltage drops. This reduces the speed of the electron beam, and thus the electrons spend more time near the deflection coils and get deflected more.

Blooming is (apparent) loss of focus at bright pixels, without geometry distortion. Blooming is a very typical effect if the picture is very bright. Turning down the overall brightness typically reduces blooming a lot. The primary source of blooming is the CRT itself.

So while breathing is most prominently due to a low-quality flyback transformer, blooming is due to a low-quality or worn-out CRT.

Hello, if it's ok to "hijack" the thread for a question, I have a FD Trinitron that has had over 41.000 hours of usage and the corners were noticeably blurry along with some geometry issues. I fixed the geometry to a very good level through the Service Mode features and then through a mix of adjusting the focus pot and re-tweaking brightness/contrast the corners were much more acceptable, although there are some convergence issues around those areas. With a tube that has had so many hours, is there anything else that can be done regarding the corner focus / convergence? Thanks

Nothing you can do much with heavily aged even "Trinitron" is just a branding and I consider Sony sneaky and restrictive. I repair TVs and monitors in past. When heavily aged monitor I knows this is that CRT coarse adjustment magnets placed on the CRT and fine adjustment in the microcontroller cannot fix this due to degraded CRT from age, including the cathodes going soft. This aging affects all CRTs of any quality including low quality ones is really worse.

Sorry about that. Best thing you can do is live with this or find a more fresher quality monitor.

Cheers,

Hello, thanks for the reply, the screen as it is right now is pretty good actually, still has very good sharpness, vibrancy and colors. I managed to squeeze every little bit that I could and now the corners are only slightly more blurry. The slightly bigger difference than normal in focus between corners and center is only noticeable in games that have text info displayed on the corners, but even that is only noticeable in some of those, depending on the font text, color and immediate background behind it.

As a learning user I was wondering if I did in fact do everything that I could or if there was something else to try, but if I did then I'll just relax and enjoy it.

Where I live Sony CRTs are just way more common than other brands, it's not a question of preference. For example, I've never even seen JVC or NEC TVs (the latter which I dearly love) for sale around here, ever. Still it was a good learning experience and it's good to know that contrary to what I've read 40.000+ hours CRTs can still be perfectly usable with good quality after some tweaks

40k hours is reaching end-of-life for a kinescope of any sort. Good video amp stages are able to bias and drive the cathodes hard enoughand avoid discoloration and especially at dark end of the brightness ramp but eventually limits are reached and discolorations will appear that cannot be corrected for.
From what I have understood, the reason for blur on a worn tube is because center of the cathode area is starting to get depleted and edge is starting to take the center stage (lol)... but edge emission makes the beam profile bigger and harder to focus down, corners are most affected because the landing angle is the steepest and beam cross-section of the beam there is largest, thus poor focus.
There isn't much that can be done about it when normal controls don't get optimum anymore. Filament voltage can be boosted and it'll buy you some extra performance at cost of accelerated aging and you can possibly boost HV a little (assuming it is separate from line scan and has adjustment available, such as in Nokia 445Z monitor) which will increase brightness and makes the beam a little narrower, improving focus, but the prospect escaping xray photons gets bigger and that is "you really need to know what you're doing" kind of thing 🤣 (not 🤣, it can be hazard to health and you need a measuring device capable of registering high energy photons to be absolutely sure you are safe).

27" JVC TVs were ones to keep! JVC TV usually have RCA CRT in these and had really good life, really good motherboard, in my repair trade I see occasional flyback or usual vertical IC failure but other than that, really good. These owners must had kept them and wore them out after around 10-15 years.

We had JVC TV for 10 years plus with one color balance adjustment midway through the life, after Sears replaced our 3 year old Sony TV, due to CRT gone out and shutting down.
When we moved, we donated it to another tenet, and bought Samsung LCD TV, still working around 15 years now.

Nec TV is half breeds using any CRT they can use.

PS, do not buy used flat CRT TVs. They don't wear well.

Cheers,

Tiido wrote on 2023-01-30, 21:41:

40k hours is reaching end-of-life for a kinescope of any sort. Good video amp stages are able to bias and drive the cathodes hard enoughand avoid discoloration and especially at dark end of the brightness ramp but eventually limits are reached and discolorations will appear that cannot be corrected for.
From what I have understood, the reason for blur on a worn tube is because center of the cathode area is starting to get depleted and edge is starting to take the center stage (lol)... but edge emission makes the beam profile bigger and harder to focus down, corners are most affected because the landing angle is the steepest and beam cross-section of the beam there is largest, thus poor focus.
There isn't much that can be done about it when normal controls don't get optimum anymore. Filament voltage can be boosted and it'll buy you some extra performance at cost of accelerated aging and you can possibly boost HV a little (assuming it is separate from line scan and has adjustment available, such as in Nokia 445Z monitor) which will increase brightness and makes the beam a little narrower, improving focus, but the prospect escaping xray photons gets bigger and that is "you really need to know what you're doing" kind of thing 🤣 (not 🤣, it can be hazard to health and you need a measuring device capable of registering high energy photons to be absolutely sure you are safe).

pentiumspeed wrote on 2023-01-30, 21:57:

27" JVC TVs were ones to keep! JVC TV usually have RCA CRT in these and had really good life, really good motherboard, in my […]
Show full quote

27" JVC TVs were ones to keep! JVC TV usually have RCA CRT in these and had really good life, really good motherboard, in my repair trade I see occasional flyback or usual vertical IC failure but other than that, really good. These owners must had kept them and wore them out after around 10-15 years.

We had JVC TV for 10 years plus with one color balance adjustment midway through the life, after Sears replaced our 3 year old Sony TV, due to CRT gone out and shutting down.
When we moved, we donated it to another tenet, and bought Samsung LCD TV, still working around 15 years now.

Nec TV is half breeds using any CRT they can use.

PS, do not buy used flat CRT TVs. They don't wear well.

Cheers,

Thank you both, I'm not a serious gamer so I won't be using that TV intensely, but I'll happily use it in its current and admittedly still good state for as long as it lasts, it was very cheap anyway. I'm just happy that it made me learn as an amateur.

Ironically I recently got another FD Trinitron, but this one only has 28 hours usage, it's practically new, and for the normal use that I give CRTs (two, three times a month on average, less even) it should last a long time. Will keep an eye on curved CRTs, always had the impression that as they were older than the flat ones they would be more wore out. I prefer curved ones for smaller CRTs, but will complement them with some "normal sized" ones as well.

For a very casual gamer I shouldn't have more than one CRT but I just love the technology and I'm pretty sure they won't ever be made again 🤣

Also, flat screens have the landing angle in the corners already suboptimal which makes it hard to get good focus and covergence there. In addition, flat shapes are weak and that is why they weight a whole lot more compared to screen that is slightly curved. Regular trinitrons are also heavier than normal as they are flat in one direction and the glass needs to be thicker to support the outside pressure.

I'd love to have a fresh tube like that, if anything just for science purposes 🤣