Fudoh's ode to old display technology

The place for all discussion on gaming hardware
User avatar
Kez
Posts: 818
Joined: Thu Jul 20, 2017 7:09 am

Re: Fudoh's ode to old display technology

Post by Kez »

So I've been wanting to experiment more with composite video and blending/dithering lately.. problem is my D20 doesn't take composite! So I bought a BKM-21D, installed it and.. it kinda works but the picture is just terrible (and no I don't mean just composite terrible!). There is like a ton of white interference and the image is kinda washed out (initially I couldn't get colour either but I was able to tweak the card settings to fix that). The BVM firmware appears to be the latest. Has anyone else experienced this, or successfully installed a 21D in a D series BVM? I have seen a few other people on this forum had similar issues but none of them ever seemed to find a solution.
Failing that, does anyone know of a good, reasonably priced RGB->Composite transcoder?
Thanks!
User avatar
kitty666cats
Posts: 1270
Joined: Tue Nov 05, 2019 2:03 am
Location: Massachusetts, USA

Re: Fudoh's ode to old display technology

Post by kitty666cats »

Kez wrote:So I've been wanting to experiment more with composite video and blending/dithering lately.. problem is my D20 doesn't take composite! So I bought a BKM-21D, installed it and.. it kinda works but the picture is just terrible (and no I don't mean just composite terrible!). There is like a ton of white interference and the image is kinda washed out (initially I couldn't get colour either but I was able to tweak the card settings to fix that). The BVM firmware appears to be the latest. Has anyone else experienced this, or successfully installed a 21D in a D series BVM? I have seen a few other people on this forum had similar issues but none of them ever seemed to find a solution.
Failing that, does anyone know of a good, reasonably priced RGB->Composite transcoder?
Thanks!
https://www.antoniovillena.es/store/pro ... o-adapter/


If you use SCART then there’s also linuxbot3000 on eBay
User avatar
Kez
Posts: 818
Joined: Thu Jul 20, 2017 7:09 am

Re: Fudoh's ode to old display technology

Post by Kez »

Sorry I'm dumb, I meant a composite to RGB transcoder, or composite -> YPbPr would work as well.
Dochartaigh
Posts: 1520
Joined: Thu Mar 02, 2017 6:53 pm

Re: Fudoh's ode to old display technology

Post by Dochartaigh »

Have you tried this? How is the conversion? (as in good quality or not? ...we all know just from using various consoles that not all composite is created equal... S-Video is usually always pretty good though).

Will it work for normal non-mister people since it seems to need 5v power from a certain VGA/DB15 pin (and I didn't think that normal VGA gave off much power, if any).

No option to take RGBS input, correct? Would have to run through an Extron RGB sync combiner or whatnot I assume, right?

...just wondering as the one thing my rack setup is missing is the ability to turn RGB into Composite/S-Video (had the old Shinybow discontinued model that did this, and the ancient Sony one too... but could never get either to work properly).
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Any idea what model Tau this might be? It's 27" but that's all I know. I'm going to go pick it up next weekend.

EDIT: Someone said it might be a CT-27SX12F

BTW does anyone know if Tau's are prone to having weird scrolling distortions? I mean that weird distortion that happens on the sides of the screen when a image scrolls horizontally. I had a Sharp XFlat that did this so badly that it was unusable because it was so distracting.
Spoiler
Image
Image
Image
User avatar
Josh128
Posts: 2123
Joined: Thu Jan 16, 2014 9:01 am

Re: Fudoh's ode to old display technology

Post by Josh128 »

Tempest_2084 wrote:Any idea what model Tau this might be? It's 27" but that's all I know. I'm going to go pick it up next weekend.

EDIT: Someone said it might be a CT-27SX12F

BTW does anyone know if Tau's are prone to having weird scrolling distortions? I mean that weird distortion that happens on the sides of the screen when a image scrolls horizontally. I had a Sharp XFlat that did this so badly that it was unusable because it was so distracting.
Like S-correction distortion? Not sure. Let us know!
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Josh128 wrote:
Tempest_2084 wrote:Any idea what model Tau this might be? It's 27" but that's all I know. I'm going to go pick it up next weekend.

EDIT: Someone said it might be a CT-27SX12F

BTW does anyone know if Tau's are prone to having weird scrolling distortions? I mean that weird distortion that happens on the sides of the screen when a image scrolls horizontally. I had a Sharp XFlat that did this so badly that it was unusable because it was so distracting.
Like S-correction distortion? Not sure. Let us know!
I think what I'm talking about is Horizontal Linearity. Are Tau's known for poor horizontal linearity?

Also I've been reading that Tau's have issues when using RGB converted into Component. Anyone know if this is true? If so this won't work for me because that's my whole setup!
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Every consumer-grade flat glass TV is subject to horizontal linearity distortion, specially if it's an early 2000 flat glass, and the larger the screen the more likely it is to have the issue.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:Every consumer-grade flat glass TV is subject to horizontal linearity distortion, specially if it's an early 2000 flat glass, and the larger the screen the more likely it is to have the issue.
My Trinitron (KV27FS100) seems to be ok in that regard. I mean I know that you're going to have a little distortion if you're looking for it, but I'm more worried about the funhouse mirror kind of distortions which I've seen on some sets (my old Sharp X-Flat for example).
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Yea, most flat glass CRTs have the speedbump effect on horizontal scrolling tests, where some parts of the screen compress the picture, expand it, and then compress it again. Vertical distortion is also a given, some are just better at hiding it.
For me, nothing will have a better geometry than curved glass barring high-end monitors.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:Yea, most flat glass CRTs have the speedbump effect on horizontal scrolling tests, where some parts of the screen compress the picture, expand it, and then compress it again. Vertical distortion is also a given, some are just better at hiding it.
For me, nothing will have a better geometry than curved glass barring high-end monitors.
How are Taus at hiding it?
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

I dont know that specific model, but it uses the same flat tube (Samsung A68QCP893X) as my Philips 27", which, in my eyes, has one of the better geometries.
https://i.imgur.com/OVA1Qde.jpeg
Just keep in mind that while the tubes can be identical, the circuit driving it is not.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:I dont know that specific model, but it uses the same flat tube (Samsung A68QCP893X) as my Philips 27", which, in my eyes, has one of the better geometries.
https://i.imgur.com/OVA1Qde.jpeg
Just keep in mind that while the tubes can be identical, the circuit driving it is not.
I can only hope it's even close to that good.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Sigh, not even close. My string of bad luck continues...
Spoiler
Image
Image
Image
Image
The geometry was okish but not good and most likely not fixable with the service menu, but the convergence is awful. You can it's completely off in the upper left corner and on the lower right side. There seems to be some overall convergence issue with the red and white squares on the left side as you can see.

I also wasn't impressed with the picture. It was kind of dark and when I turned up the brightness then the grid got those 'squiggles'. Also I could see some blooming on the bottom when I when I adjusted the brightness from full to half so that was going to be an issue with games as well I imagine. I didn't even bother to check the scrolling and see if it had that horizontal linearity problem. At least this time I didn't drag it down to my game room and tested it upstairs so I don't have to haul it back up those stairs.

I just can't seem to win the CRT lottery like others do. I'm starting to think I should give up on the component and look for a nice curved CRT with S-Video, buy an RGB to S-Video converter and be done with it. I don't think I'm going to take another chance on an untested CRT as getting rid of them is expensive or impossible in my area.
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Tempest_2084 wrote:I also wasn't impressed with the picture. It was kind of dark and when I turned up the brightness then the grid got those 'squiggles'. Also I could see some blooming on the bottom when I when I adjusted the brightness from full to half so that was going to be an issue with games as well I imagine.
I had an LG TV like that, definitely a tell tale sign of a very worn tube. Also had pretty bad focus and convergence outside the center which I couldnt fix even with a new yoke and flyback. The TV's luminance should be checked before getting it, if the brightness is at like 80% or more, and adding contrast makes things blurrier, it's without a doubt an end of life tube. All my good TVs stay at 20~40% brightness.

You can try finding a curved set with component though.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:
Tempest_2084 wrote:I also wasn't impressed with the picture. It was kind of dark and when I turned up the brightness then the grid got those 'squiggles'. Also I could see some blooming on the bottom when I when I adjusted the brightness from full to half so that was going to be an issue with games as well I imagine.
I had an LG TV like that, definitely a tell tale sign of a very worn tube. Also had pretty bad focus and convergence outside the center which I couldnt fix even with a new yoke and flyback. The TV's luminance should be checked before getting it, if the brightness is at like 80% or more, and adding contrast makes things blurrier, it's without a doubt an end of life tube. All my good TVs stay at 20~40% brightness.

You can try finding a curved set with component though.
There was a picture of it working (linked above) but the more I think about it, that picture was letterboxed due to it being broadcast TV so the issues I saw with the corners wouldn't have been detectable. If I ever go get another CRT I'm going to do a full test before I take it. If the person won't allow that then I won't take it. I'm tried of being stuck with trash TVs. Although in this case I don't think it was intentional, the person I got it from was very nice about everything. I used to just check the geometry on sets before taking them, now I know I need to check geometry, convergence, scrolling (horizontal linearity), and bloom. I wish there was a bloom test in the 240p suite as outside of some games (all SNES) I'm not sure of a good way to check it on the fly. My spare console I bring out to these things is a Genesis.

Curved CRTs with component are hard to find. I've had two so far and both had issues. The Sharp I had had some convergence issues in the corners and the corners were pretty blurry (I think the tube was worn out) and none of the geometry could be adjusted even in the service menu. The JVC D-Series I currently have looks good (although I had to crank up the screen voltage to get a brighter picture) but has terrible bloom issues which make many games almost unplayable (the screen ungulates so bad it's distracting). I don't know if the voltage regular needs to be recapped or what (can it be replaced?) but it's BAD. There are some pictures of it a few posts back if you're curious.
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Tempest_2084 wrote: If I ever go get another CRT I'm going to do a full test before I take it. If the person won't allow that then I won't take it. I'm tried of being stuck with trash TVs. Although in this case I don't think it was intentional, the person I got it from was very nice about everything. I used to just check the geometry on sets before taking them, now I know I need to check geometry, convergence, scrolling (horizontal linearity), and bloom.
I learned this the hard way with the trash LG I got. I noticed it had weird purity issues on all corners and brightness cranked to the max, but I assumed I could just fix it somehow. The tube was basically dead and I had to give away the TV to charity, wasted some money on parts too (new FBT, new yoke).
Buying a TV without looking at the picture first is a lottery, and I admit I've done this many times and got lucky, but luck eventually runs out...
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:
Tempest_2084 wrote: If I ever go get another CRT I'm going to do a full test before I take it. If the person won't allow that then I won't take it. I'm tried of being stuck with trash TVs. Although in this case I don't think it was intentional, the person I got it from was very nice about everything. I used to just check the geometry on sets before taking them, now I know I need to check geometry, convergence, scrolling (horizontal linearity), and bloom.
I learned this the hard way with the trash LG I got. I noticed it had weird purity issues on all corners and brightness cranked to the max, but I assumed I could just fix it somehow. The tube was basically dead and I had to give away the TV to charity, wasted some money on parts too (new FBT, new yoke).
Buying a TV without looking at the picture first is a lottery, and I admit I've done this many times and got lucky, but luck eventually runs out...
Quite frankly I think I'm going to have to buy a TV from a person in the hobby. Yes it's always nice to get a great TV for free, but I'd rather spend some money and get what I want and know it's good than constantly playing the lotto and hoping for the best. It's not the wasted time that bothers me, it's the fact that you can't just dump the TV on curb for the trash to take. Around here you have to take it to a disposal place or wait until your county has a free hazardous waste disposal day (which have been mostly cancelled due to covid). Thankfully I was able to get a free voucher for a recycler and they took this one, but if I hadn't had that free ticket it would have cost me about $80 to get rid of (75 cents a pound they said).
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Tempest_2084 wrote:It's not the wasted time that bothers me, it's the fact that you can't just dump the TV on curb for the trash to take.
I've seen some amazing curb pickups, but, more often than not, thats the truth behind "free" CRTs and curb finds. Sometimes it's worth paying for something that actually has a good picture and is in good condition.
Fed
Posts: 16
Joined: Wed Apr 01, 2020 11:22 am

Re: Fudoh's ode to old display technology

Post by Fed »

What always saddens me is to think that the TV was doing fine until just before it was dumped in the street meaning it suffered all the damage on the way from the house to the place it was dumped. :cry:
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Tempest_2084 wrote:I decided to dig out some of my other 'backup' CRTs to see if they're any better than my Sony. First up is my Sharp 27SC260. It's a nice curved screen CRT that does component (don't know if the curved screen is a huge benefit or not). Looking at the grid however I noticed that the grid lines were 'squiggly' in spots. I tried to take some pictures but I don't know if the squiggles show up to well (you can see them pretty well in the convergence grid screenshot). Is this something that I should be worried about? I couldn't see how it affected the picture any, but I thought I read somewhere that this meant the caps were going. Beyond that, there's some small convergence issues on the top horizontal line (barely noticeable and better than my Sony) and the geometry on the top right edge isn't the best but it's not bad. I was actually thinking about using this one instead of my Trinitron but there are two issues. 1. The picture isn't as sharp (no pun intended) and 2. I can't adjust the geometry at all (the SM options don't do anything).

I'm wondering if I open it up and adjust the focus knob (assuming it has one) if I can increase the sharpness a little, but the corners are already slightly blurrier than the center screen so I don't know if that would be a good idea. I really do miss those Trinitron scanlines too. The second problem isn't too bad, but the picture really needs to be shifted a smidgen to the right and down as some games that like to use the entire screen are very slightly cut off. I could live with it if I had to, but it's really annoying that I can't do anything about it.

Any comments on this particular tube vs my Trinny?
Spoiler
Genesis Grid
Image

Genesis Convergence
Image

SNES Grid (see the squiggles on the right near the red?)
Image
Quoting myself here. What would be the best way to try and fix the convergence issues in the corners on this set? Is that a yoke adjustment or magnets or something else?
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Blurry corners is never a good sign, none of my good sets have that.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:Blurry corners is never a good sign, none of my good sets have that.
Any idea on how to fix it?
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

Pull up solid color patterns and check for uniformity. If the red looks greenish/blueish where the blur is, then it's probably a worn tube. I had one like this, not even yoke adjustments or magnets could fix the issue.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

tongshadow wrote:Pull up solid color patterns and check for uniformity. If the red looks greenish/blueish where the blur is, then it's probably a worn tube. I had one like this, not even yoke adjustments or magnets could fix the issue.
Yep I think that's the problem. I cracked it open and other than the focus knob there wasn't one adjust anywhere, plus the yoke looked bonded with no magnets so that wasn't even an option. Oh well.
yoZe
Posts: 31
Joined: Wed May 18, 2011 11:16 pm

Re: Fudoh's ode to old display technology

Post by yoZe »

tongshadow wrote:Blurry corners is never a good sign, none of my good sets have that.
Blurry corners is an inherent flaw in crt technology, unless you have a dual focus screen like a pc monitor or a bvm, you can't do anything about it.
Fed
Posts: 16
Joined: Wed Apr 01, 2020 11:22 am

Re: Fudoh's ode to old display technology

Post by Fed »

The blurriness could be caused by bad convergence, can you upload a picture of a white grid ?
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Fed wrote:The blurriness could be caused by bad convergence, can you upload a picture of a white grid ?
There was massive convergence issues in the corners too. I didn't see a way to fix that as there was no way to adjust the yoke or magnets to adjust. This one is a lost cause I'm afraid. It's not a huge loss though as I'm pretty sure now that the tube was badly worn due to some other evidence:
tongshadow
Posts: 613
Joined: Sat Jan 07, 2017 5:11 pm

Re: Fudoh's ode to old display technology

Post by tongshadow »

yoZe wrote:
tongshadow wrote:Blurry corners is never a good sign, none of my good sets have that.
Blurry corners is an inherent flaw in crt technology, unless you have a dual focus screen like a pc monitor or a bvm, you can't do anything about it.
Im talking about REALLY blurry corners, like, unreadable HUD elements. I have many CRTs of many sizes but one particular 29" LG was so bad I got rid off it, and it look liked Tempest's picture.
User avatar
Tempest_2084
Posts: 593
Joined: Tue Feb 04, 2014 3:05 pm

Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

So I've decided to take another crack at fixing the geometry on my PVM-1943MD. As you can see from the picture it's not bad, but there's definitely room for improvement. The biggest issue is in the lower right corner as it is pulling up making the bottom edge uneven. This isn't a tilt problem as the top of the screen is level. Actually the upper right pulls down a bit, which is another issue. The final problem is that the upper right corner also pulls inward a bit.

I've done all the adjusting I can using the internal controls (standard adjusts like Pin Amp, Pin Phase, V Angle, etc.), so now I think I need to use magnets to fix these geometry issues. I tried using convergence strips, but the yoke already has a ton of them (factory installed) and getting new ones in there is tough. They also didn't seem to do much with the geometry, but had a tendency to screw up the convergence. However I rescued some magnets from a CRT I was getting rid of that I'm hoping might help. They're flat L-shaped things, and look like something you'd use to stick things to a refrigerator. Would these help? I've never tried playing with magnets directly on the tube and I'm a bit nervous that I might screw something up. Any tips? Where on the tube is the 'safe zone' for placing magnets? I don't want to screw up the grille.

Recapping this CRT isn't something I can do, so that's not an option.
Spoiler
Image
Post Reply