Fudoh's ode to old display technology

[hitz]

Does anyone know what would cause this on my Ikegami TM20-80RH? It only happens with RGBS, if I hookup component and set the RGB/YPBPR to YPBPR there isn't any of the distortion or whatever you would call it. Same with composite being used. It only seems to show up when using RGB no matter what system is used.

[Ed Oscuro]

any of the distortion or whatever you would call it

I literally don't know what I'm supposed to be looking at here, so I can't call it anything. The only thing I see that doesn't look about correct, or obviously down to camera settings (i.e. the tint) is the appearance of blue to the right of the trees, and strangely nowhere else. Hopefully somebody knows what this is to help you - maybe it's some kind of defocus issue. If you could confirm what the specific problem is with more description, that'd be good. Unfortunately, photos often aren't immediately usable due to differences in color capture and reproduction in both the camera and our own monitors.

May well be that there's not enough blue in the image, but you seem to imply that it looks fine with other connections, so at the least the tube itself should be fine in that case.

[bobrocks95]

There are blue streaks to the right of everything if you view the picture full-size- bits of grass, the score, the rings, etc. And the image is SO green I don't see how any remotely modern camera could mess up the tint so badly, so I'm guessing that's a problem too?

[Ed Oscuro]

All the same, typing details helps takes the guesswork out of it and get us oriented quicker. Blue looks misaligned but I think we're also seeing the other colors at wrong levels - either red is too low (the word "rings" is quite red, but maybe it's too dark) or green is too high (likely; there's a green tint over everything).

Another data point for this: Taking the first picture here, and then capturing a still of Sanic and Tales idle in the same place from this video, and cropping both images to show roughly the same amount of play area (i.e., getting rid of the bezel of the PVM which shows a lot of green reflected, as well as most of the orange blocks from the YouTube screencap which don't show up in the photo - the only other obvious difference is "RINGS" shows in yellow in the screencap, but changing this to red only altered the following R and G values by less than 1%), I looked at the histograms:

Photo - avg. R 77, G 136, B 98
Emu cap - avg. R 86, G 94, B 94

So it looks like red is too low in the monitor, but the major story is green is way too high (relatively speaking). Blue looks actually consistent between the two monitors - and altering saturation of red and green (slight boost to red, big nerf to green) improves the color balance.

On a third try, I have to agree that blue is just shifted to the right everywhere. It's not noticeable in the grass, but looking at the screen edge, we see where the displaced blue is much more notable to the edge of the grass, and basically absent against the blank sky.

Incidentally the blank sky is almost black in the photo, but in reality it should be a very dark blue. This might well be down to the camera. However, I recall reading something a while back about the background of a title screen in Three Wonders looking wrong in MAME due to voltage levels doing funny things on real monitors that wasn't seen in the emulation. Hopefully that's not relevant to this case.

Still, the story here should be - everything has to be checked by eye and confirmed; pictures across the Internet aren't reliable, especially if some details (like the fact the Sonic 2 sky has a color) are easily forgotten.

[bobrocks95]

I guess I underestimate the ability for cameras to ruin everything

[Ed Oscuro]

Edited my post, changed my opinion on the overall tint being due to the camera, but you'll be surprised - it's still quite possible for it to fool us in subtle ways. I have to agree that the blue shift isn't likely due to the camera, but I didn't have to change my opinion there.

We only have a vague reference of what the screen looks like here, since the brightness level and white balance, at the very least, used in the camera aren't known here.

In the meantime would be appreciative if we could keep this on-track with making sure the OP knows that subjective opinions really are mandatory in addition to the pictures. In fact if I had my choice of one or the other, I'd ask for just the subjective opinion first. The ability to do some data comparisons is nice but many small factors can ruin the assumptions behind my comparison.

[BazookaBen]

My guess would be that there are some missing caps or resistors in the RGB cable. The custom cable I made for my Genesis 2 follows this diagram, though it terminates with BNC instead of Scart.



Before I added the resistors and caps, the picture was too bright and would lose sync.

[kowal]

Hi
My tip for Extron Emotia BNC to SCART if TV requires a voltage on 8 and 16pin
find VGA to BNC have 5 wire
cut one BNC and put on end male plug DC 3,5mm
made small hole on case and USE DC 3,5 male plug


I use 5V from PCB

extron emotia have scart socket (BNC ver is solder secondary)
on scart point 16 pin is +5V
on pin8 +10,5V
but you can not use them

5v wire must be connect aganist 100R
GND connected to 21 pin (or to other GND point)


on scart plug 5v come to 8pin ->100R>16pin


and is end

[Ed Oscuro]

But this isn't a TV and it obviously doesn't require a voltage to switch into RGB mode - just look at the on-screen display in the picture.

It seems strange to me that this would be a resistor-related problem, but it does make sense, even though the symptoms don't appear exactly the same (sync doesn't appear to be dropping, unless the OP didn't tell us, and green appears out of line with the other colors).

[kowal]

Yes is tip for extron user not for this problem

but
a similar picture is displayed when the LCD monitor has a VGA connector and someone use adapters component to VGA and try send componet (example PS3) signal to VGA socket
if monitor does not have a function component on VGA you get similar image all is green

It may be a similar problem with sync

[Ed Oscuro]

Sorry, forgot what thread we were in for a moment

Probably best to do a quote if you're replying to something on a previous page.

[jedman]

Ive noticed some uneveness on the picture on my BVM. its not noticeable on a static image, but in motion it can be seen on certain colored backgrounds. it looks a bit like the backlight clouding you get on lcd's, down the centre of the screen it looks like there is a very faint vertical stripe.

It's hardly noticeable but does anyone know what is causing this?

Is it just the age of the crt?

Thanks

[Fudoh]

My tip for Extron Emotia BNC to SCART if TV requires a voltage on 8 and 16pin

that's a nice solution! Well done.

Just a general note: pin 8 can cause the TV to display a wrong aspect ratio. To get RGB working you only need a voltage on pin 16. For RGB that's between 1 and 3V. That's why +5V are usually routed to pin 8 and then - through a resistor - to pin 16.

[cicada88]

Can someone give me a good idea of what I should look to pay for a PVM-20L5 and a PVM-14L5. Definitely used, unknown amount of hours, no apparent problems.


I believe these are late model and capable of up to 1080i

I just need a ballpark reasonable price range here.

US$

[MysticSynergy]

I've noticed something odd on my Sony BVM when looking at Art's 240p Test Suite - specifically the Grid view.

Every dot looks perfect except for the middle horizontal line. Those dots are not square but "flat" and look squished. Is this something I need to adjust with focus? Apart from opening up the TV and adjusting the pots that way, is there a internal menu setting I can to adjust the focus?

[Artemio]

Just to discard it, which version of the suite are you using? Some old versions for dreamcast could only output 239 Visible lines, since that's what the sdk did. The documentation and interactive help mentions that, it might be the case.

If you are using the latest versions from the site, then that is not the cause.

[MysticSynergy]

Thanks Artemio - I think I'm currently using the 5/22/2014 release, but I'll double check. I see there is a 6/28/2014 version so I'll download that and give it a try.

Btw, the test suite is so incredibly helpful and easy to use. Wanted to throw out a HUGE thanks for making it!!! You rock

[Artemio]

Thanks Artemio - I think I'm currently using the 5/22/2014 release, but I'll double check. I see there is a 6/28/2014 version so I'll download that and give it a try.

Btw, the test suite is so incredibly helpful and easy to use. Wanted to throw out a HUGE thanks for making it!!! You rock

Just checked, I got full resolution in the Dreamcast version by changing the default PVM register values from the SDK on 5/30/2014, so that should be the source of your issue. The help does document that it is only 239 lines in that version though =)

As a result the central row of pixels in the grid is only 1 pixel tall.

I always fear these stuff may cause issues for others, so I try and document them when I notice them... sorry about that.

Thanks a lot for your kind comments though, it is a great hobby.

[jedman]

When playing PAL PS1 ones games say, If I simply increase the vertical size in geometry to get rid of the borders, will it be the same quality of image as If I played the NTSC version? I know it will still be slower but was wondering If the PAL image is simply squashed and can be stretched out manually.

[Fudoh]

Yes, the pixel alignment and everything else is identical.

[Jono]

Hiya again guys,

I've got my Bandrige 5 SCART selector switch connected to my BVM-20F1U and I noticed that it has AV inputs and I had an interesting theory:

Could I use my Bandridge box to hook up my NES and have the BVM to worK? So far, no. However, I went into the Input Selection on the BVM Menu and it's blue'd out. From my understanding, this means I cannot edit or make changes to this setting, does anyone know why I cannot, or if what i'm trying to do is even possible? It'd make thing's significantly easier on me to get multiple game consoles hooked up. I don't think S-Video will work however...

If anyone knows about this, please let me know!

[Fudoh]

By default the BVM does not have a composite decoder. You need an extension board installed (e.g. the common 21D SDI board) to get composite support on all BNC inputs. Same for s-video, needs a different decoder though.

[jedman]

Ive noticed some uneveness on the picture on my BVM. its not noticeable on a static image, but in motion it can be seen on certain colored backgrounds. it looks a bit like the backlight clouding you get on lcd's, down the centre of the screen it looks like there is a very faint vertical stripe.

It's hardly noticeable but does anyone know what is causing this?

Is it just the age of the crt?

Thanks

Anyone else noticed this? Can be seen easily on the sky in shadow of colossus if you rotate the view around.

[Ed Oscuro]

If there is a thin line, it's an anchor wire for the Trinitron aperture grille. Otherwise it makes me think of burn-in.

[jedman]

If there is a thin line, it's an anchor wire for the Trinitron aperture grille. Otherwise it makes me think of burn-in.

Yeah its not the anchor wire, its not as distinct as that and its thicker, running vertical. more like a clouded area which is slightly darker than the rest of the screen, but only visible when the screen moves across a background area of greyish colour.

Also noticed it in super mario word on some of the background areas when the screen moves horizontally. But on other colours or textures it can't be seen at all.

[Ed Oscuro]

It's starting to sound more like burn-in, perhaps of a specific phosphor combination.

[Ed Oscuro]

If anybody's in Texas, here's a PVM-20L2MD for you:
http://www.publicsurplus.com/sms/auctio ... uc=1233723

Looks like it's in great shape, probably low hours.
Auction will expire in two hours but you can probably just call them up.

[philexile]

A little off topic, but where did you get those colored BNC cables?

[philexile]

By default the BVM does not have a composite decoder. You need an extension board installed (e.g. the common 21D SDI board) to get composite support on all BNC inputs. Same for s-video, needs a different decoder though.

And its built-in comb filter is pretty impressive. Picts (iPhone, sorry) are taken from a SNES Mini outputing composite to a 34" Sony BVM:

Normal


Comb


Normal


Comb


Normal


Comb


Its not RGB, but its really not bad at all for composite.

[kowal]

philexile
Unfortunately in Poland
http://allegro.pl/nowy-kabel-d-sub-vga- ... 03054.html
made by Thompson, very cheap 4-5$. But I dont see this on Ebay
colorful BNC looks similar to the original Extron