crt tv rgb input

[mahalos]

hey guys

i'm looking at purchasing a tv for my new arcade project. I've already picked up a 29" grundig with scart inputs but it's not a flat screen (which is easier to bezel) and it's kinda large at 29". I saw this tv  http://www.trademe.co.nz/Browse/Listing.aspx?id=383966125
on our local auction site and wondered about the RGB 31.5khz input. Can you make a direct connection from your vga card into this??

any help appreciated

[Jack Burton]

31.5khz is basically the same as 640x480@60hz resolution.   If you have a graphics card that will support that, and 99.9% do, then it should work

That TV is just another 29" tube though.  

Both of these are excellent choices for an arcade display.  What kind of games do you plan on playing on it the most?

[mahalos]

Thanks for your reply, i generally play horizontal fighters and quite a few vertical shooters. 27" is a slightly nicer size to work with i thought, and if i can get it cheap enough i thought it'd be a good option. I just didn't know too much about the RGB input, i've seen plenty with VGAs but not RGBs, and was wondering if they were any good.

[Jack Burton]

There's no such thing as a 27" tube.  It's just different measuring systems.

Televisions are often measured by their visible viewing distance, while monitors are measured by the size of the actual tube.

Do to the bezel surrounding the television screen you can only see 27" of video.  However, the tube inside is probably nearly the exact same size as your grundig tv.  

You have a dilemma on your hands here.  There's quite a few good fighting games for both 15 and 31khz monitors.  I say get them both.  

Also, VGA is RGB.  RGB isn't really a video standard of it's own.  It comes in a variety of designs like RGBS, RGBHV, RGsB, SCART, CGA, VGA, CMPTR, etc.   The actual difference in video quality between them is mostly negligible.  It's all a matter of getting the right cables and adapters to get video from the device to the display.  In the case of the RGB 31.5khz connector, you've got it just about as good as it gets.  A regular ol' VGA cable is all you need.  

[boardjunkie]

Thats pretty nifty. What model is it? I might keep an eye out for one at the local "junk stores" since upscale CRT tv's are really becoming common and sell for peanuts.

Now what are they doing with the VGA input to get it to std res? Scaling down the sync to std res freq's?

[Jack Burton]

I would assume there is no scaling going on at all.  The TV is likely a very early generation HDTV.  These TV's are now known as EDTV's, or Enhanced Definition TV's.  It will display the 31.5 khz signal as it is intended to be seen.

31.5 khz is also another term for 480p, or is sometimes known as Progressive Scan. 

[mahalos]

well i just managed to pick up that tv for $40.....pretty happy about that. I'll be interested to see how it's going to run.

[Jack Burton]

Even if you don't use it for arcade gaming it will surely be a nice TV to hook a computer up to and use as a multimedia center. 

480p video on a properly calibrated CRT can look NICE.

[mahalos]

One last question (hopefully). Is it ok to use a DVI to VGA adaptor as i've only got cards with DVI out? I've never used a TV for a cab before, only arcade and PC monitors, and have certainly never used one of the adaptors before.

[Jack Burton]

Yes, most DVI ports include the pins for VGA. 

[mahalos]

So i picked up the tv today, fired it up.....and i have a problem.  There's doesn't seem to be any red.

I've tried different cables, and two different pc's, but the results are the same. I have no colour adjustment on the TV for the RGB input, only size controls. I've tried tweaking with the nvidia utility on the PC, but had no luck. I'm unsure where to go from here.
 
The TV is a panasonic tx-68p150z with a 31.5khz rgb input. The video card is a 8800gts outputting 640x480.

The picture looks really good...apart from the colour!!

The other problem i have is the fact that the RGB osd display doesn't seem to go away...(must try and download a manual)

...and the fact that when the power is cut, and turned back on it starts up on channel 6. If it's left on one of the 4 AV channels it's starts back on them fine....it's just the RGB input that it refuses to startup on.

[boardjunkie]

You have to get into the service menu for color (and other) adjustments. But, thats not yer issue. You have a missing color, so its likely a cathode drive transistor on the neck board that is either bad or cracked loose from the board. Its possible the color signal is missing further up the line.....you'd need to poke around with a scope to see where it goes missing. If you take it to a repair shop you should be able to get it taken care of fairly cheap.

[lilshawn]

can you get red from a channel or another input?

[Jack Burton]

Hmmm, I think somehow you're sending it the wrong signal.

On displays that have RGB inputs if you hook up a Component cable you will get "green screen" effect.  It looks just like what you have. 

I'm wondering if your computer is somehow detecting a tv here and is deciding to send YpBpR over the video cable  instead of straight RGB.

So we need to answer a few questions:

#1: Can you see correct colors when using the other inputs?

#2: What kind of cables are you using to connect?

#3: What kind of adapters are you using?  

[mahalos]

yes,  i can get red on the TV using any of the AV channels and the composite out from my digital camera.

I've tried 2 VGA cables.....both using the DVI to VGA adaptor, I also found a DVI to VGA cable that came with one of my monitors.

Thinking it may have been something to do with the DVI on my pc, I tried using the VGA output on my laptop.

All cable, adaptor and pc combinations gave the same result.

PC = winxp, nvidia 8800gts, DVI output
laptop = win 7, intel HD graphics (or something like that), VGA output

[Jack Burton]

If you can get red from one of the other channels then your tv is fine.

It's  just a matter of getting the right signals and the right settings.  

There is a manual here for the TX-68p250z, which has the same "RGB 31.5 khz" connector:

http://www.google.com/url?sa=t&source=web&cd=9&ved=0CFYQFjAI&url=http%3A%2F%2Fwww.elektroda.pl%2Frtvforum%2Fdownload.php%3Fid%3D357972&ei=u1H-TZWzEsXl0QGZvsDdAw&usg=AFQjCNFB7EV7cPMXIJTlEblQX780fuousw

According to the manual you are doing everything right.  

You need to look all over and see if you can find anything about switching Component, also known as YpBpR, to RGB.  Any kind of external switch or button, some kind of option in the menus.

You can try other stuff like the other DVI input on your card, different DVI-VGA adapters, etc.  It would be very helpful to try a VGA source that you know for sure can't output component video. 

Does the Nvidia control panel recognize the monitor?

[lilshawn]

maybe this is supposed to be used with the tvs rgb port... 

http://www.bhphotovideo.com/c/product/312047-REG/Sanyo_POA_CA_COMPVGA_POA_CA_COMPVGA_15_Pin_Mini_D_Sub.html

[Jack Burton]

It's certainly possible, but unlikely as the diagram in the manual doesn't mention it.  

It could be that the TV is just not compatible with certain graphic cards, and the OP has been unlucky enough to have two computers that won't work.  

I've had a few different "pro" monitors that had issues with newer Nvidia cards, from having green screens to just showing nothing at all.    

My suggestion is to just try more sources.  

If you look at that screen shot of Mortal Kombat running you can see the match timer is all black.  If he had a bent or missing pin then it would just be colored a mix of blue and green.  But if you send component over RGB then it actually does get some red signal and it makes this weird dark, dark, reddish black.  

[MonMotha]

Tear the two DDC pins out of a VGA cable (that you don't care about otherwise), hook it up, and force everything to 640x480p.  Windows should just identify it as a "non-plug and play monitor" and pretty much go into dumb, "I'll do whatever you say, boss, because I have no idea what you've hooked me up to" mode.  Verify that you're gettting all three colors, with the same cable, on a PC monitor, then swap over to the TV.

[mahalos]

well now, I figured i'd try booting into linux(my main OS) this morning to see if there was a difference in how it handled the output.....

low and behold we have red!! i used the DVI to VGA cable i had. Was about to write a quick reply saying how hopeless windows was but thought i'd better try it again.... so booted back into XP and the picture was all good as well.....mmmmm

Had to head off to work so couldn't test any further,  but it leaves a few unanswered questions??

[lilshawn]

i lean towards loose connection or bad solder joint on the tv input

[mahalos]

yeah, that was my first thought to,  but with the amount of times i plugged and unplugged cables into the thing i thought i my have seen the red flicker in or out.....i do remember giving the plug a bloody good wobble to see if there was a loose connection.

I managed to get ahold of a manual, this helped me get rid of the RGB display on the screen but there seems to be no way to solve the fact the TV starts back up on ch6 after being powered down whilst on the RGB input. Dunno know if i can get past the fact that i have to push the AV button   4   times to get it onto the RGB input,  it's really gonna drive me crazy.

Maybe i'll have to grab me a ArcadeVGA and test out the VGA to SCART on the 29" Grundig. You'd have to imagine the components in the grundig would be better than the panasonic??

[apfelanni]

usually the more expensive tv sets can be set in osd to start with the channel u prefer. others remember the last active one when the tv is switched off or in standby. my ( naomi ) grundig with vga in always starts with av4 ( vga ) when turned on . i havnt encountered any probs unless the input is 640x480 with 60 hertz , no matter its coming from a pc or a console like dc or xbox .

- get a service manual or google for service mode
- make sure your computer and cable are set to work properly

 - the vga plug on your tv can be damaged
 - vga in may have to be activated or set up in the osd to work as expected    
 - maybe the firmware of your tv doesnt support vga
 - maybe u need a special cable for the connection

some time ago i tried to enable a metz 100 hertz tv for vga input via scart . i figured out that a metzmade secret cable was needed and i had to flash a new firmware to suppport vga . that was a real horror . so i deciced the grundig with a plug n play vga modul would be a wiser choice.

i wouldnt say grundig is of better quality than panasonic . i all depends on the modell and fab year. lots of old grundigs of the 80-90 ties keep running for 20 years or more . but after 2003 its beko turkey stuff inside. on the other hand panasonic build some very good tubes . whats your grundig modell and cuc number ? i can tell if its worth the effort. btw soft 15 k will do fine . no need for a avga .

ps. usually the rgb or av displaying in the corner can be turned off in osd. 

 

[mahalos]

thanks for all the info...

I stopped the RGB displaying, thanks to the manual i found.

The TV has no option in the OSD menus to set the start-up channel.....bummer.

The Grundig is a  M 72-410/9 reference,  CUC 1842

[Jack Burton]

Have you tried any 31.5khz games on the TV yet?  I'm kind of curious to know how they looked.  

Any Atomiswave or Naomi game like Hokuto No Ken or Guilty Gear should look incredible.

[apfelanni]

there are 2 versions of the grundig 410 reference . one comes with vga input per factory default , the other without the modul . its a solid top class 100 hertz tv with a very good picture and speakers. the chassis is huge and devided into 2 parts , what makes mounting into some cabinets not that easy. the tube is a nice curved toshiba . i recommend to use it with the vga input and not with mamescart . i m not sure if the vga - scart adapter works on this tv set. if it comes to retrogaming and mamescart ure better up with a 50-60 hertz tv.

i bought a reference 410 as monitor replacement for my naomi . because the tube is curved it didnt fit the flat bezel of my virtua striker naomi . so i went with a xentia mf 490 instead ( flat toshiba with vga input ) and replaced moms 20 year old tv with the reference 410 . she is so pleased with it that she wont give it away anymore ( not to mention it perfectly fits with her furniture).

[mahalos]

Have you tried any 31.5khz games on the TV yet?  I'm kind of curious to know how they looked.  

Any Atomiswave or Naomi game like Hokuto No Ken or Guilty Gear should look incredible.

Haven't tried any of these yet, I got side tracked today after remembering my Grundig had a VGA port, so have been playing around with that....I must say, I'm really impressed with the picture, the games look fantastic. The geometry is a little out (curved inwards on the sides) the user menu only has adjustment for horizontal and vertical, but i'm hoping the service menu might have the same sort of parabola adjustment the Panasonic set had.

I'm really really stoked with the quality of picture, I'll be over the moon if i can sort out the TV's to start up on the VGA inputs.

[apfelanni]

autostart av5 / vga for cabinet use : keep the power button pressed and switch on cabinet power . the tv remembers the latest used channel .

the osd service ( code 8500 ) offers a wide range of adjustments . the vga port handles 3 different resolutions / refreshrates. 

[BurgerKingDiamond]

There's no such thing as a 27" tube.  It's just different measuring systems.

Televisions are often measured by their visible viewing distance, while monitors are measured by the size of the actual tube.

Do to the bezel surrounding the television screen you can only see 27" of video.  However, the tube inside is probably nearly the exact same size as your grundig tv.  

You have a dilemma on your hands here.  There's quite a few good fighting games for both 15 and 31khz monitors.  I say get them both.  

Also, VGA is RGB.  RGB isn't really a video standard of it's own.  It comes in a variety of designs like RGBS, RGBHV, RGsB, SCART, CGA, VGA, CMPTR, etc.   The actual difference in video quality between them is mostly negligible.  It's all a matter of getting the right cables and adapters to get video from the device to the display.  In the case of the RGB 31.5khz connector, you've got it just about as good as it gets.  A regular ol' VGA cable is all you need.  

maybe you can explain this to me. I have computer monitor I got on craigslist that has a regular VGA input and also RCA jacks for RGB. It came with a cable the has a VGA plug that goes into the PC VGA port and breaks out into the RGB RCA plugs that go into the monitor. If VGA and RGB are the same then why does this have both? What's the point?

[BurgerKingDiamond]

I guess it's just 2 choices of how you want to connect based on what cable you have. It seems kind of pointless because regular VGA cables are common. I've never seen one that breaks out into the 5 plugs before.

http://www.dll.com.mx/biblioteca/Monitors/Viewsonic/P815%20Specs.pdf

[boardjunkie]

Those aren't RCA connectors, they're likely BNC connectors.

[boardjunkie]

Using the BNC inputs is kind of a manual configuration that can have better results in certain situations.

[BurgerKingDiamond]

Those aren't RCA connectors, they're likely BNC connectors.

I don't know the difference between RCA and BNC. I just thought that RCA plug was a generic term for those kinds of plugs. They look the same as what you would see in component cables or regular Audio/composite cables (I think.. I can't remember exactly what they looked like. I'll check when I get home, it's bothering me now trying to remember.)

[Jack Burton]

BNC connector (Female)



Phono AKA RCA connector (female)



The BNC connectors are for use with high resolutions.  At extremely high resolutions a regular VGA cable can have a lot of noise over it. 

For use as an arcade monitor there is no difference in image quality, although the monitors themselves may have slightly different abilities or settings for each input. 

[lilshawn]

BNC's are popular on higher end equipment because of the positive connection you get when you push and lock them on, the connection is good, the impedance is matched.  everything is good... they are designed to perform.

RCA's are cheap, dirty, and was more or less designed in a hurry. there is no real specification with regards to cabling. quality over RCA's is generally poor which is why many manufacturers have begun to move away form RCA.