Fudoh's ode to old display technology

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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Some people are suggesting that I do a yoke adjustment, but I don't see any reason to touch the yoke. The convergence is near perfect and my last experience with playing with a yoke didn't go so hot. I do see that the Pin Amp needs to be adjusted a bit now, looking at a smaller version of the picture makes it rather obvious.
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

I managed to place one magnet in the lower left corner to bring up the dip. It may look basically the same as the original picture, but I also extended the vertical size to get rid of the gap at the bottom of the screen. Doing this made the lower left square in the corner get cut off on the bottom before I added the magnet.

I'm trying to pull the upper right corner out a bit, but I'm having trouble with the convergence there too. The problem is getting to the right middle and bottom corner is difficult due to the power board in the way so I need to be very careful (I accidentally brushed against it and got a warning tingle).
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atohmdiy
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Re: Fudoh's ode to old display technology

Post by atohmdiy »

Hello,
Seems to be the place to talk of crt. Two years ago i bought two bvm 2010p, both with dead psu. I don't manage to repair their psu so i was a little stuck with these two.
A kind soul offer to send me a working psu. With the new psu, one monitor is working, the other wasn't.

The non-working monitor show no image, it seems to come from high voltage. Indeed after replace the high voltage protection board, the monitor power-up, but the image is a little blurry and the color are mixed around the screen. High voltage on the left is doing a "clac clac" rhythmic noise. The person that send me the working psu will get the monitor and try to repair it.

I will keep the "working" monitor, that by the way have a beautiful image, colorful, very bright. Cannot get the geometry to be perfect though but i still think some board need serious recap. Problem is, the monitor is starting to make some buzzing sound after some time powered-up. At power up there is the usual very light high-pitch noise from the main psu, then after 15 min or so, strong buzzing appear (constant sound), and seems to come from the high voltage bloc on the left. I found one of the convergence pot in the drawer to actually control this. If i turn the pot down, the buzzing attenuate a lot, and become strong when i get the pot up to have the convergence right. Other control like brightness do not seems to have any impact. When i was moving the convergence pot, a high pitch noise also add itself to the strong buzzing, i preferred turn off the monitor at this point, but i never see the buzzing to have some impact in the picture quality.
Any idea how to solve this ?
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Before I continue with playing with the magnets I want to make sure I have to geometry more or less the best it can be with the limited internal adjusts this PVM offers. Basically I'm stuck with only Pin Amp, Pin Phase, Bow, and V/H size/position. There's also a vertical linearity adjust I believe.

Looking at these two pictures (one with a flash to show the bezel better), can I fix the remaining issues with these adjusts or do I need to start putting on more magnets? The biggest issues I see are that there's an inward bow on the left side (which may be causing the top corner to angle out) and that the top left is too high and needs to be pushed down so it matches the position of the middle and right top edge.
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kitty666cats
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Re: Fudoh's ode to old display technology

Post by kitty666cats »

I mean, isn’t the red the near-threshold of the overscan region anyway? I’d personally just raise H and V size a tiny bit & call it good, the OCD rabbit hole of perfecting geometry is the mind-killer (I know it all too well, lol)
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

kitty666cats wrote:I mean, isn’t the red the near-threshold of the overscan region anyway? I’d personally just raise H and V size a tiny bit & call it good, the OCD rabbit hole of perfecting geometry is the mind-killer (I know it all too well, lol)
So you think it's good enough as is?
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kitty666cats
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Re: Fudoh's ode to old display technology

Post by kitty666cats »

Were it me, I’d overscan the red borders out but have the dots still visible, or riiiight on the border of the screen. I’d maybe also give it one tiny pincushion adjustment so that the middle goes outward a wee bit

…Like ‘ (_) ‘, and not ‘ )_( ‘

Aside from this hypothetical tweak, I think that it looks pretty dang solid! Heck, it may not even look like it needs a pincushion adjustment outwards after all, if you increase H size a little bit. The inability to see the curvature of the screen IRL may be playing tricks on my eyes
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

Is there a good way to see if the squares towards the center are straight vertically? I tried using a piece of paper but the set is curved so there's no good flat bottom to put it against.
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

I played around with it a bit and here's where I got it. It's looking pretty good, but I worry that the grid kind of bows inward at the bottom (look at the red row on the bottom left). I don't know if playing with the BOW adjust will fix that or just mess it up elsewhere. Or am I just imagining it and this is all due to the screen being curved? In the underscan pics you can see how the top seems to 'bend outward'. What do you think?
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Underscan
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kitty666cats
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Re: Fudoh's ode to old display technology

Post by kitty666cats »

Looks even better than before! Highly doubt you'd even notice anything during actual use, at that point
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

kitty666cats wrote:Looks even better than before! Highly doubt you'd even notice anything during actual use, at that point
You'd be surprised actually. It's really noticeable when, for example, you have a list of text scrolling down like with my NES PowerPak menu. The text started to curve inwards towards the bottom. Same deal with Metroid, the bricks in the vertical tunnels curved inward at the bottom and it was fairly obvious. I adjusted the bow a bit and fixed that problem but as you can see now the right lower corner now bows inward pretty badly. However this fixed most of the other issues I had so I'm thinking I can use a magnet to fix that corner. I had to do something similar with the lower left corner (it dipped down pretty bad).
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EDIT: The more I look at that picture, I think I curved it too far left, I'll have to ease it back a bit.
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

I managed to get a magnet taped in the lower right corner (not easy with my meaty paws) that fixed 95% of the problem. It's not 100% perfect, but it's good enough I think. You be the judge:
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I'd like to try and fix the upper left corner since that has a bit of a rise to it, but that's not too noticeable. The difficult part is fixing the geometry without completely whacking out the convergence. I'm really happy with the way this is turning out. I'll probably replace my 27" Trintron with this.

Someone told me that the linearity might be off (the squares are too narrow). Would the V Linearity adjust help with this?
thchardcore
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Re: Fudoh's ode to old display technology

Post by thchardcore »

You use the larger square or circular magnets to get the geometry corrections. The smaller plastic strips that go near/under the yoke are only for corner convergence correction. They are done in that order.

If you have purity issues after and your monitor does not offer purity adjustment (entire screen and/or corner "landing"), then you need to use a chevron shaped magnet to correct that which will barely change the geometry.

It is mostly trial and error, but less error as you get better at it.
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

thchardcore wrote:You use the larger square or circular magnets to get the geometry corrections. The smaller plastic strips that go near/under the yoke are only for corner convergence correction. They are done in that order.

If you have purity issues after and your monitor does not offer purity adjustment (entire screen and/or corner "landing"), then you need to use a chevron shaped magnet to correct that which will barely change the geometry.

It is mostly trial and error, but less error as you get better at it.
Yeah I've discovered that. I fixed the upper left corner so I have the geometry about as good as it's going to get I think. I used the 'chevron shaped' magnets I scavenged from a dead TV as I figured those would be safe and not damage the tube. I didn't need to push the geometry too far so they worked really well.

Now I need to work on the linearity with that monoscope pattern (the top squares look stretched vertically). This unit has a V Linearity adjust so hopefully it will be pretty easy.
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

So I fired up the monoscope pattern but I have no idea how to use it to check the linearity. The two red boxes are wider than they are tall, which I think is the way its supposed to be for 4:3. But how do I figure out when I have the linearity correct? The FAQ has this to say:
Linearity. Is the hardest part of the deflection circuit. Scrolling tests are the best way to confirm good Linearity but some compensated square elements have added to each corner where a tape measure may help get you started.
I guess I can start measuring the squares, but are they supposed to be perfectly square or are they supposed to be wider than they are tall? If so, how much wider? To me the SNES grid looks alright, but the squares on the top of the Genesis grid look taller than they should.

Any help on this would be greatly appreciated.

EDIT: Ok so I've been told that what I need to do is adjust the V Linearity until the top and bottom crosses (SNES pattern) are the same height and the two large red squares are both actually square. Does this sound right?



SNES Patterns
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Genesis Patterns
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Tempest_2084
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Re: Fudoh's ode to old display technology

Post by Tempest_2084 »

I fixed the linearity issue (I think). Short of trying to figure out which system I want the screen centered for (the SNES and Genesis seem to disagree), I think I'm done.

EDIT: Ok I did some checking on all my consoles:

TurboDuo - Shifted Left and cut off. Ok with underscan
Neo Geo - Centered but cut off even with underscan (not surprising)
PSX - Shifted Left and cut off. Ok with underscan
NES - Centered and perfect
Saturn - Shifted Left and cut off. Ok with underscan
SMS - Centered and perfect. Everdrive menu is shifted Left and cut off slightly though
N64 - Shifted Left and cut off. Ok with underscan but still some cut off on the left
SNES - Slightly shifted left. Doesn't need underscan
Genesis - Shifted right. Overscan helps

So It appears that the bulk of my newer systems are shifted left and cut off unless I underscan it (which makes me lose a good inch on all sides). But the NES, SMS, and SNES are pretty much perfect and the Genesis isn't too bad. Not sure what to do now...

Genesis Grid (notice how it's off center right)
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SNES Grid (more centered)
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NES (CV 3 showing how the left is cut off a bit)
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atohmdiy
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Re: Fudoh's ode to old display technology

Post by atohmdiy »

Hello,
A seller is offering a bvm-a32 in a french website. It's not very farm from my home, i can make the journey if it's worth, but the monitor have issues.
The seller said "the three color are not aligned, there is also problem with the red channel. It is likely to be the tube". The monitor have nearly 22k hours, i find it strange the tube have problem with such low hours, but i recall reading somewhere that big 32' bvm have problem with their tubes.
If the tube is dead indeed the monitor is useless, but if it's an electronic problem it could be worth picking. What do you think ?
There is some photo in the bid :
https://www.leboncoin.fr/image_son/2129223255.htm
tongshadow
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Re: Fudoh's ode to old display technology

Post by tongshadow »

900 euros for a 100kg paperweight? Yea, bad deal. It doesnt even have the good cards.
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Re: Fudoh's ode to old display technology

Post by SuperSpongo »

atohmdiy wrote: i find it strange the tube have problem with such low hours, but i recall reading somewhere that big 32' bvm have problem with their tubes.
If the tube is dead indeed the monitor is useless, but if it's an electronic problem it could be worth picking.
As far as I know, the D32 tubes had issues and were replaced under warranty. But that would have been sorted by the time the A32 was released.
Having said that, I also think the tube is bad and the monitor is not worth buying if you don't have a plan and know-how for any sort of tube swap.
atohmdiy
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Re: Fudoh's ode to old display technology

Post by atohmdiy »

Smells fishy indeed, the seller answer this :
"I get this monitor for 4 years, it was working but keep power on and off succinctly. But the image was good. I tested myself the 3 cathode of the tube (i said tested) with a rejuvenator and it indicates a short between the G1 grid and the red cathode. By moving the monitor to another room, the short disappear and move to the green. Since then the image is like that. So the electronics is perfect, the problem definitively come from the tube. So yes i am selling the monitor for parts only."
So the monitor have some power issue for a long time, then this tube problem appear. I'm skipping my turn on this one, it's a shame really as it's the ultimate dream monitor, but i haven't the knowledge to repair it and i live too far of any competent tech.
Out of curiosity, is there anything to do to repair the short in the tube ?
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Re: Fudoh's ode to old display technology

Post by H6rdc0re »

Wow that A32 has been running for 90000 hours. Would never buy that one not even for 200 euro's.
atohmdiy
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Re: Fudoh's ode to old display technology

Post by atohmdiy »

I don't know if this "operation time" do not include power on plus sleep. And "CRT Turn on time" the "real" power on operation time. Or maybe the tube was replaced after some times ?
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Re: Fudoh's ode to old display technology

Post by fernan1234 »

I like how the empty card slot tells you that a 68X card was harvested from the monitor.
tongshadow
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Re: Fudoh's ode to old display technology

Post by tongshadow »

Well it wouldnt even work as a "parts only" because the BVMs are modular, so in practice you're just buying the tube and chassis, and the power supply. Nothing really can be salvaged.
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Re: Fudoh's ode to old display technology

Post by H6rdc0re »

Does anyone know if a 15khz PVM can pass through 480p signals? I want to connect my Dreamcast with a Retro Gaming Cables scart cable to my 20L4 and then pass through to a PC CRT monitor so I can run 240p/480i games on my PVM and 480p games on the PC CRT monitor.
tongshadow
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Re: Fudoh's ode to old display technology

Post by tongshadow »

H6rdc0re wrote:Does anyone know if a 15khz PVM can pass through 480p signals? I want to connect my Dreamcast with a Retro Gaming Cables scart cable to my 20L4 and then pass through to a PC CRT monitor so I can run 240p/480i games on my PVM and 480p games on the PC CRT monitor.
I vaguely recall being able to passthrough component on my 14M4U even when it's turned off, so I assume that yes, it should work.
tongshadow
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Re: Fudoh's ode to old display technology

Post by tongshadow »

Ok, I got it to work. Pretty neat setup for PS2 games, if I want 480i I just stay on the PVM, 480p gets sent to the monitor through the PVM's RGB output.
https://i.imgur.com/k0hoHgA.jpeg
H6rdc0re
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Re: Fudoh's ode to old display technology

Post by H6rdc0re »

tongshadow wrote:Ok, I got it to work. Pretty neat setup for PS2 games, if I want 480i I just stay on the PVM, 480p gets sent to the monitor through the PVM's RGB output.
https://i.imgur.com/k0hoHgA.jpeg
Does the PVM also pass through the signal when turned off?

What I'm looking to do is pass the signal from my first PVM to my second PVM (TATE MODE!!!) to my CRT monitor.
tongshadow
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Re: Fudoh's ode to old display technology

Post by tongshadow »

Yes, it does passthrough even off.
H6rdc0re
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Re: Fudoh's ode to old display technology

Post by H6rdc0re »

I'm looking to recap my PVM 20L4s. I remember for some PVMs Sony had a technical bulletin saying to upgrade some caps to higher values. Does anyone know if there was any bulletin about the PVM L4 series?
tongshadow wrote:Yes, it does passthrough even off.
Thanks, great info.
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