Mod a CRT to increase its TVL

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nes.og
Posts: 134
Joined: Sat Apr 04, 2020 7:01 pm

Re: Mod a CRT to increase its TVL

Post by nes.og »

Syntax wrote: Wed Jul 02, 2025 12:21 am
nes.og wrote: Tue Jul 01, 2025 11:21 pm Thanks for the info @vol.2

Does the mod really increase TVL if you use a TVL test pattern or does it just make the scan lines sharper?
Correct, It makes your monitor look like a hi res screen displaying low res content, horrible scan lines.
But kids these days froth on them scanlines. So hence this thread.

Get ready for a page of BS claiming TVL is increased. The only thing increased is the gap between them.
I assumed it didn’t actually increase real TVL or the TVs would have been set this way out of the box. I assumed it would make scan lines sharper as in finer and less visable like a higher TVL tube but maybe “sharper” wasn’t the best way to convey that.

If it makes them stand out more than it is not something I’m interested in since scanlines already really stand out on some tubes especially large ones with have a larger dot pinch. I have a Sony and Misubishi were the scanlines are already distracting.
nes.og
Posts: 134
Joined: Sat Apr 04, 2020 7:01 pm

Re: Mod a CRT to increase its TVL

Post by nes.og »

nes.og wrote: Thu Jul 03, 2025 8:48 am
Syntax wrote: Wed Jul 02, 2025 12:21 am
nes.og wrote: Tue Jul 01, 2025 11:21 pm Thanks for the info @vol.2

Does the mod really increase TVL if you use a TVL test pattern or does it just make the scan lines sharper?
Correct, It makes your monitor look like a hi res screen displaying low res content, horrible scan lines.
But kids these days froth on them scanlines. So hence this thread.

Get ready for a page of BS claiming TVL is increased. The only thing increased is the gap between them.
I assumed it didn’t actually increase real TVL or the TVs would have been set this way out of the box. I assumed it would make scan lines sharper as in finer and less visable like a higher TVL tube but maybe “sharper” wasn’t the best way to convey that.

If it makes them stand out more than it is not something I’m interested in since scanlines already really stand out on some tubes especially large ones that have a larger dot pinch. I have a Sony and Misubishi were the scanlines are already distracting.
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vol.2
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Location: bmore

Re: Mod a CRT to increase its TVL

Post by vol.2 »

nes.og wrote: Thu Jul 03, 2025 8:48 am
I assumed it didn’t actually increase real TVL or the TVs would have been set this way out of the box. I assumed it would make scan lines sharper as in finer and less visable like a higher TVL tube but maybe “sharper” wasn’t the best way to convey that.

The author of this thread and his followers use a definition of TVLs that encompasses the effect of this mod. Luke referenced technical white papers written by television engineers that count the TVLs in such a way that it includes the spot size of the electron beams decreasing towards the minimum dot pitch of the phosphors. Once you hit the phosphor spot size, decreasing the spot size any more makes the moiré pattern visible in the raster because at that point it's smaller than the size of the shadow mask holes/slots/grill.

So Luke and others would argue that it does increase TVLs. I suggested that they revise the terminology but they were dead set against it (especially Luke). I think the point of using TVLs was to garner more attention for it, and it sure worked. I kind of don't like when people do stuff like that though; I would prefer that things are done in the most unsensationalized way possible. That keeps people more level-headed when it comes to expectations, and it doesn't get a bunch of inexperienced people to do dangerous things with the promise of improving their image quality.

But that didn't happen. As it stands, I don't think many people are talking about this anymore because it's a known quantity now. Once all the attention disappeared, Luke moved on; said he only likes tube TVs now or something. Go figure.
nes.og
Posts: 134
Joined: Sat Apr 04, 2020 7:01 pm

Re: Mod a CRT to increase its TVL

Post by nes.og »

Thanks for sharing. I’ll work on doing the mod and using the TVL test pattern before and after to see if the count changes.
LukeEvansSimon
Posts: 129
Joined: Mon Aug 17, 2020 7:28 pm

Re: Mod a CRT to increase its TVL

Post by LukeEvansSimon »

Image
(Click image for full size)

I occasionally check back in on this thread and chuckle when I see that there are still people that are digging in their heels claiming the G1 mod doesn’t work. They don’t understand the tech, and are incapable of inventing anything novel or making any contributions to the CRT gaming community. But they still complain a lot about those who do understand the tech and who make contributions.

Here are good side-by-sides for G1 mod paired with an RGB mod: https://www.reddit.com/r/crtgaming/s/GgxAffAcTd

Anyway, you can buy pre-made mod kits now. I am not affiliated with the seller and I don’t make any money from its sales, but just wanted to contribute to the community, so check out the kit:
https://www.rgbmods.com/products/g1-mod-kit

Here are videos showing how it is installed:
https://youtu.be/USRP-l8v0b4
https://www.youtube.com/live/25vA804P3k4
SuperSpongo
Posts: 353
Joined: Sat Mar 17, 2018 2:49 pm
Location: Germany

Re: Mod a CRT to increase its TVL

Post by SuperSpongo »

Hey, good to see you're still interested in the topic :)
I was just about to say, there are quite a few people that know about and implement this mod now.

I have yet to install one of the boards that I got from ElBartoME (I'm so lazy lol). I have a KV-C2981D at home the tube of which I rejuvenated already. It does not have dynamic focus and I have to compromise between center and corners. I'm sure the G1 mod would further improve the picture.

Maybe this weekend...
nes.og
Posts: 134
Joined: Sat Apr 04, 2020 7:01 pm

Re: Mod a CRT to increase its TVL

Post by nes.og »

Wild anyone would prefer the 2nd image with the mod.

LukeEvansSimon wrote: Thu Sep 04, 2025 3:14 am Image
(Click image for full size)

I occasionally check back in on this thread and chuckle when I see that there are still people that are digging in their heels claiming the G1 mod doesn’t work. They don’t understand the tech, and are incapable of inventing anything novel or making any contributions to the CRT gaming community. But they still complain a lot about those who do understand the tech and who make contributions.

Here are good side-by-sides for G1 mod paired with an RGB mod: https://www.reddit.com/r/crtgaming/s/GgxAffAcTd

Anyway, you can buy pre-made mod kits now. I am not affiliated with the seller and I don’t make any money from its sales, but just wanted to contribute to the community, so check out the kit:
https://www.rgbmods.com/products/g1-mod-kit

Here are videos showing how it is installed:
https://youtu.be/USRP-l8v0b4
https://www.youtube.com/live/25vA804P3k4
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Josh128
Posts: 2351
Joined: Thu Jan 16, 2014 9:01 am

Re: Mod a CRT to increase its TVL

Post by Josh128 »

I would like to try it on my 36XS955, but I really have no clue. I think the tube could use a rejuv, but I think thats not possible still on Trinitrons.
lazyelm
Posts: 21
Joined: Sun Jan 19, 2025 12:33 am

Re: Mod a CRT to increase its TVL

Post by lazyelm »

Amazing post - thank you - inspiring! - I'm responding in hopes of some pointers or suggestions

Hi folks - I've done this mod successfully on a number of JVC's - av and D series. The results are quite obvious and i love it. I am doing this on my KV-35s45 currently and running into a challenge. I am using a pre-built g1 mod board - I've got it set up like this:

- On the flyback
Im tapping the flyback on the -15v pin on the flyback - i measure up to -135v on the neck side of the mod board with the pot maxed out. I've also used the 200v pin and i get about -235v on the neck side of the mod board with the pot maxed.

- On the neck board
i am tied into all 3 of the g1 pins from the neck side of the mod board
I have lifted the 2 resistors and 1 diode that are connected to pins so they are isolated

Adjusting G2 and G1 doing really do much of anything - on this TV
- G2 doesnt really give more or less brightness like i usually see - adjusting has a very very minor impact on brighness where the colors get a tiny bit more or less rich, but its like a threshold, really can other be on one side or the other of the trheshhold - and even so the adustment is extremely minor. Too low G2 and the screen shuts off, too much and i get retrace lines (as expected) and the screen shuts off
- G1 mod pot does pretty much nothing on this TV- other than when i hit about -75v or lower it just shuts the screen off
** worth noting i have done a rgb mux mod - thats been running and fine for months.

Any thoughts or suggestions one whats going on or what i could do here?

Flyback and neckboard on pages 25 and 31 of this schematic
https://dn721906.ca.archive.org/0/items ... 105345.pdf

im using this mod board - https://www.rgbmods.com/products/g1-mod-kit

thanks!
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