Sunday, 11 January 2015

Adding RGB to a non-SCART television

Welcome to 2015 (AKA "The New Zealand Story")!

It's been a while since I dropped an update here... but I'm okay with that since I have a whole swag of solid excuses.

Since my trip to the High Scores arcade in San Francisco I've:
  • Moved country (Aussie to Kiwi)
  • Started a new job (Document Controller)
  • Bought a new car (crappy Opel Astra)
  • Got engaged (to Olivia)
... you could say it's been a busy few months. ;)

In between all this, of course, I have collected a bunch of CRTs and gadgets. I even have myself a couple gutted arcade cabinets that were from an arcade in my new hometown (Dunedin, New Zealand.)

Before we talk about any of that cool stuff, I want to show off my latest project... adding an RGB input to a non-SCART television! The thing that drove me to delve into this is fact that my cabs need a couple 21 inch monitors... and the combination of RGB to YUV converter I bought and component television I tried just didn't do it for me.

Now, before we get to the glorious RGB money shots, I need to say a big thank you to 133 MHz and Tim Worthington. Without their expertise and willingness to share their knowledge, there's no way I would have ever pulled this off (or even thought to do it in the first place). I'll post an entry of all the necessary links soon but, in the moment, let's take a quick tour:

Nice old Sanyo 25" that I picked up for $5
Sanyo C25ZG51 (chassis AA1-A25)
Chassis before being introduced to my air compressor!
Sanyo A59KPR84X (SI) tube
The TDA8361 Jungle IC that was under all that dust
Using the UMSA for composite sync and 5v output
Wiring up RGB and sync outputs plus a control voltage
75 ohm termination for the RGB lines (so important!)
Using an LM317 to set the Fast Blanking voltage
Insert points for the blanking and RGB
Composite sync via the composite video input
And... BAM! We have RGB!!!
And we have MAME!!!
Super Monaco GP (World, Rev B, FD1094 317-0126a)
Sega, 1989
320 × 224 @ 59.637405 Hz
Knights of the Round (World 911127)
Capcom, 1991
384 × 224 @ 59.637405 Hz
The NewZealand Story (World, new version) (newer PCB)
Taito Corporation Japan, 1988
256 × 224 @ 59.150000 Hz
As well as all this 15 kHz progressive resolution glory, interlaced modes work just fine too!

Dead Or Alive ++ (Japan)
Tecmo, 1998
640 × 480 @ 60.000000 Hz
Thanks to a handy vertical size pot, this TV can also be quickly adjusted for 256 line games!

R-Type II
Irem, 1989
384 × 256 @ 55.017606 Hz
I have to say the this Sanyo tube performs very nicely. Check this zoom-in:

Close-up
This is an extremely exciting development! This changes the nature of my CRT pursuit considerably! No longer am I restricted to the SCART option when it comes to RGB monitors!

There's a lot more detail to discuss with all this... and I'm hoping to write a generalised step-by-step guide for this modification.

In the meantime, I can report that my success was not limited to this one television. Check out this nice 20 inch Philips radiating new-found RGB goodness:

20 inch Philips with a similar Jungle IC
Amazingly, the second TV only took about 30 mins to modify. I didn't even have the proper schematic for this TV! Knowing what the pins on the TDA jungle chip do, I was able to pinout the RGB and blanking lines using a digital multimeter. Then, I simply changed over my breakout cable from the Sanyo to the Philips. Flicked the power switch and saw the above RGB picture 3 seconds later! Amazing!

To be honest, weeks of reading and research have gone into this. But now I know how, recreating this mod would be faster than soldering a VGA to SCART cable. And the results are better for several reasons (that I'll explain in the future).

For the moment though, the dream of cheap and abundant arcade replacement monitors has become a reality!

Philips de-cased and ready for a transplant

12 comments:

  1. Congrats on the engagement.

    One thing that Jomac/Joey's universal chassis lacks is composite decoding, because of its arcade intended use only.

    Are the modified chassis capable of running composite or svideo inputs as intended? Or once modified, can the TV only accept RGB? I can see this as a benefit for console gamers, being able to run SCART RGB along with composite/svideo for the consoles which don't support it, all on a TV which does not support SCART RGB.

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  2. Hey! Thanks!

    Yeah, for sure! The trick would be to install a 4PDT switch for the blanking and three (RGB) video signals. That way you could switch between the RGB input and the normal, unmodified operation.

    The RGB, S-Video and Composite options would, indeed, be a benefit over a Jomac chassis. Plus, you don't need a video amp to connect a PC via VGA. And the price... both these TVs cost $5 each (and I was being generous). The image quality on the Sanyo, in particular, is outrageously good.

    Of course, the pros for a Jomac job are the excellent support and lack of hacking.

    I have a whole folder of links that I researched before attempting this. I'll make a page with them all when I get a chance... I just wanted to get something up quick to prove that this method isn't a myth!

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  3. Hey Paradroid,

    This is great! I had heard about this type of mod but had the impression that it was completely model dependent.

    Looking forward to seeing all the details. Intrigued by the 75 Ohm resistors, maybe it's a coincidence that we have to use those too when forcing arcade monitor detection.

    Good luck with your new job and everything.

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  4. Thanks!

    Yeah, I think this is a pretty cool development, especially for GroovyMAME users who aren't in Europe!

    I believe that since the RGB input is so direct, problems such as vertical centering offsets (PAL/NTSC) are eliminated. I'm not entirely certain about this but this seems the case so far. Certainly, vertical centering was perfect without any monitor spec alterations (just used a GroovyMAME monitor preset and everything was spot-on.)

    Also, you don't see the annoying RGB lines above the image is always the case with SCART televisions. This means you don't have to pad the image downwards in order to hide them with overscan. Same as an arcade chassis in this regard.

    The mod is certainly model specific but I'm thinking in terms of the video processing IC model rather than the TV model number. If we could create a list of compatible Jungle ICs and chassis specific insertion points then the appeal could be great for non-European CRT enthusiasts. The basic concept is generic but implementation details will vary.

    As I said, there's lots to discuss! I'll compile all my bookmarks when time permits...

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  5. Ha! looking forward to these developments, having a bear of a time finding scart compatible tv's here back in aus, and once I did I can't seem to get it working.. :( glad it seems as there is another option.

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  6. I love this post and so want to do the same. Some schematics (even hand written in draft formate) would be awesome. I'll even Visio the diagram for you for free if you want (love my Visio 😊).

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  7. I want to try to do this. It would mean the universe to me if you made a video of how to do this step by step, as long as you have the time. (I learn a lot better by videos)

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  8. I'm interested in doing such mod for my Trinitron KV2584MT. Also I need some tips'n'tricks to restore good geometry. I hope it won't involve replacing every cap :|.

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  9. I recently did this with a Sony KV-G21S2. There's a point on the board for the Teletext module with the RGB and Blanking pins clearly labled (on the underside). It looked like it was already terminated properly, so I just connected the RGB lines directly to it off a SCART connector, the composite and audio on the existing AV1 input and it all just worked!

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  10. pgodwin nice work indeed, I have the same tv and have done the mod now too. Picture looks great and I am also using radeon hd4350 with soft15hz for the full Mame experience.
    I also have a NEC FS-6361 tv which I have located RGB/blanking on but cannot get it to sync sadly... Have tried AV inputs, sync stripped via a LM1881 on AV and H/V sync pins on an IC I found but nothing.. Anyone have any experience with NEC TV's ? I cannot find the service manual online.

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  11. Hey! What's the Jungle chip in your NEC? I have a 20" NEC under the house but haven't cracked it open yet to attempt a mod...

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