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ideal Monitor/Display for the TI-99, and the TMS9928A video chip

Sony PVM Sony BVM TMS9928A YPrBr RGB 240p CRT Broadcast Monitor Professional Video Monitor

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#1 kl99 OFFLINE  

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Posted Mon May 15, 2017 5:53 AM

Hi guys,

I would like to know your experiences with Monitors/Displays for running your TI-99, be it the US version (Composite) or the (European) PAL version using the YPrBr, or via the french RGB modulator RVB PHA 2037.

Also I would like to know whether anyone tweaked his US console with a TMS9928A to get YPbBr out of it? It looks to me this is the best video chip to maintain the original desired speed of 60 Hz but getting the video signal via 3 component lines.

 

The official TI branded 10" monitor is nice, I am missing the option to have RGB or YPrBr input. Even though there is supposed to be a PAL Version, that is nowhere to be found.

 

I know about the F18A as video chip alternate with VGA output, I have two at home, however I am aiming for one setup now running the original experience.

Sprites look so much more organic if there is Scanlines.

 

In regards to the Monitor, I read a lot about Sony PVM CRT (Sony Professional Video Monitors) being the ideal displays for Retro Gaming since they don't upscale or screw up the video by believing it's interlaced content. Their geometry and quality is supposed to be outstanding. And from watching videos running RGB modded game consoles I can only agree with them. Sony PVM means they were not meant for the Consumer market but for the Professional market and therefore super expensive. Above that level is ever a higher class called Broadcast Video Monitors (Sony BVM). Those have even higher quality standards. Those devices can be feeded via Composite Input but you should aim for YPbrBr or RGB video as Input for those.

Here is some example video, there are lots out there, it's kind of hard to capture the quality of those devices since they are from CRT (interlaced) running 60fieldsPerSecond and Youtube has 30fps:

 

People talk a lot about 240p meaning, even though the console renders two fields via it's analog video out ports the content of those two fields match one progressive frame. A lot of TVs/Upscalers treat the ouput wrongly as 480i and starting to process the video with which then the problems starts.

 

BR Klaus


Edited by kl99, Mon May 15, 2017 6:42 AM.


#2 gfreige OFFLINE  

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Posted Mon May 15, 2017 8:54 AM

Hi, I've connected my PAL TI99 to a multitude of displays using the YPbPr output with a custom made cable. You don't need to modify anything in the console. Most displays worked fine, except for a TCL 46" LCD display (UNSUPPORTED in the screen) when used YPbPr, but working fine with only the Y signal via Composite input, in B&W.

Despite working in both Sonys I've tried, a DELL monitor with YPbPr input and a Panasonic plasma (it's actual display) voltages aren't standard. The blue signal is too high so all colors have a bluish tint. I was able to correct it in the DELL using a custom color setting, but in the other displays colors were too cold. Of course your display needs support for PAL signals.

This is the pinout of the PAL TI. Just connect Y to Green, Pr to Red, Pb to Blue (try some resistor to lower Blue channel signal if you want), Audio to Left and Right audio channels, and all grounds to Ground.

Attached File  7896.png   191.84KB   2 downloads

Also, if you tweak an US TI win the 9928A, you'll end with a PAL, 50Hz console. The opposite is true with a PAL TI with a F18A, it'll run at 60Hz. The VDP commands the hertz rate. not the console.

Regarding scanlines, if you use an old 640x480 VGA monitor (CRT of course) with the F18A you'll have the same (or very similar) scalines than  a NTSC display (both have 480 lines at 60 Hz)


Edited by gfreige, Mon May 15, 2017 9:02 AM.


#3 Asmusr OFFLINE  

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Posted Mon May 15, 2017 9:25 AM

Also, if you tweak an US TI win the 9928A, you'll end with a PAL, 50Hz console.

 

9929A is for PAL. I think the 9928A is generating 60Hz signal, but I have never heard about anyone using this chip.



#4 gfreige OFFLINE  

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Posted Mon May 15, 2017 9:49 AM

 

9929A is for PAL. I think the 9928A is generating 60Hz signal, but I have never heard about anyone using this chip.

 

Of course, as usual, you are right. I've mixed the 28A and 29A, misunderstanding the whole point of the question :)



#5 Ksarul OFFLINE  

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Posted Mon May 15, 2017 5:27 PM

There were instructions for adding a 9928 BITD, so there are probably some consoles out there with this mod. . .



#6 Tornadoboy OFFLINE  

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Posted Mon May 15, 2017 6:50 PM

There's what this guy did to mod it for RGB:

 

http://retrogamingti...m/rtm42/#modded

 

Although it involves cannibalizing a Baby Pacman PCB that typically aren't cheap, but the used circuit is fairly simple if one wanted to build it from scratch. I've got the schematic and might take a crack at it someday so I can hook a TI up in a coin operated arcade cabinet, I've always thought Microsurgeon would be awesome with Robotron-like controls! 


Edited by Tornadoboy, Mon May 15, 2017 6:55 PM.


#7 kl99 OFFLINE  

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Posted Tue May 16, 2017 4:00 AM

Thanks for the replies so far.

 

Going into the YPrBr mode with a TMS9928A is definately interesting. There is a huge benefit over Composite Video, and not much difference to RGB, since the YPrBr is created inside the chip like that and any conversion of an analog signal is at best as good as the original.

I will try to find out if and what postprocessing is necessary besides fetching those 3 pins with ground.

 

I have ordered a Sony BVM monitor now, it should be running any NTSC/PAL and 15khz as well as 31Khz signals. It handles YPrBr and RGB with any sync in addition to composite.

For me the money is worth invested since I not only want to run any TI-99 (US/Europe), but as well the other computers I have using the TMS9918(A) like the Tomy Tutor and the Colecovision.

And I can finally do proper gaming with my retro consoles again. There is even a custom graphics card driver that enables 15khz modes to run MAME properly on a CRT:

http://wavebeam.blog...that-plays.html



#8 kl99 OFFLINE  

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Posted Wed May 24, 2017 2:00 AM

The Sony BVM arrived. This is a beast. Now I need the right cables, everything is BNC only. I have found one single Cinch2BNC connector in my household, but had no success so far with getting a picture from my Pal Nintendo NES.

The monitor is completely anti-Auto. So everything has to be manually defined and set, mostly counter-intuitive.

I have ordered a set of BNC terminators and Cinch2BNC connectors in order to connect something.

 

It will be interesting to see how good the NTSC TMS9918A is gonna look via composite on such a monitor.

I also want to compare the raw YPrBr 50hz output of a TMS9929A with the RGBs 50Hz output from the french RGB modulator RVB PHA 2037.

More in the next days (currently feeling sick)....



#9 Ksarul OFFLINE  

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Posted Wed May 24, 2017 4:57 AM

Gute Besserung, Klaus! (Get well soon, Klaus!)



#10 kl99 OFFLINE  

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Posted Thu May 25, 2017 12:00 AM

Thanks Ksarul.

 

The cables and BNC parts are ordered.

Yesterday I was able to connect the Tomy Tutor console.

The video quality was not bad even though it was composite.

However I am really looking forward to YPrBr since the TMS9918A composite output is known to not be very clear.



#11 kl99 OFFLINE  

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Posted Sat May 27, 2017 12:59 PM

With the BNC parts having arrived I can now at least test YPrBr devices like the TI-99/4A, Pal in 60Hz.

I must say, the Sony BVM D24E1WE is delivering a spectactular image for the TI-99/4A, Pal 60Hz. I didn't even started to calibrate the video yet.

Almost have I forgotten how good Parsec looks with all those scanlines being there.

 

All my fiance said, it is flimmering, you can not use it like this. So expectations are different for each one.

Once I have more energy and time I will try to compare it with a F18A output.

 

Not a single photo or video I took was doing the picture quality justice.

With a 50-60Hz interlaced display It is super hard to capture the experience.

The colors looks like they are bleeding when taking a photo, camera was a iphone 6s.

Attached Files



#12 kl99 OFFLINE  

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Posted Sat May 27, 2017 1:03 PM

some more...

Attached Files



#13 kl99 OFFLINE  

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Posted Sat May 27, 2017 1:12 PM

The BNC 75 Ohm Terminators will arrive on Monday.

To use it with my other consoles that output RGB via Scart Port I ordered a breakout cable to connect it properly to this monitor:

http://www.ebay.com/...EUAAOSwrklVRfWO

 

The screen should work with the Geneve and the 80 Column Cards as well.

 

Here is a brochure about this monitor, the D24E1WU is handled in the retrogaming community as in the Top 5 CRT ever produced:

http://www.broadcast.../bvmdseries.pdf

Attached Files



#14 schmitzi OFFLINE  

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Posted Sat May 27, 2017 3:55 PM

hmm, I think there are same disturbing waves in the lines, on the bottom, and they are NOT parallel. That does not look good.

 

 

 

 

 

 

 

 |

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V

 

 

 

 

Attached File  Disturbing-Wave-Lines.jpg   48.79KB   0 downloads

 

Aaaah STOP, this is you T-Shirt :-D

 

 

.



#15 HackMac OFFLINE  

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Posted Yesterday, 2:52 AM

Nice...

I'm searching for a Sony BVM-14F5E or something like that (or a PVM model) for quite some time. But this monitors should have a SDI connector... (I'll try to generate such vido signals with my FPGA.)

 

 

 

Send from my Hackinosh using Firefox


Edited by HackMac, Yesterday, 2:56 AM.






Also tagged with one or more of these keywords: Sony PVM, Sony BVM, TMS9928A, YPrBr, RGB, 240p, CRT, Broadcast Monitor, Professional Video Monitor

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