Need Help to Add an S-Video Port to my FS-A1 MKII

Por AyaNicodemos

Supporter (1)

imagem de AyaNicodemos

13-03-2020, 15:52

Hello Everybody,

I Need some help to add an S-Video port on My FS-A1 MKII,
RGB Monitors are rare and expansive in Brazil and S-Video are more commom, it'll be the secound mod of my MSX, and with that i'll make a Video/Blog Tutorial of All Mods of the Computer.

Thanks in Advance
Aya Smile

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Por sdsnatcher73

Prophet (3012)

imagem de sdsnatcher73

14-03-2020, 11:06

If you want internal mod I guess it would make sense to look at FS-A1WSX’ schematics as this has built in S-Video

Por gdx

Enlighted (5352)

imagem de gdx

14-03-2020, 11:59

On this page in Japanese it is written that we can do that with a NJM2288 connected to the SONY CXA1145 as he did on an FS-A1FX. The circuit diagram is here. It seems very simple to do.

Por sd_snatcher

Prophet (3502)

imagem de sd_snatcher

14-03-2020, 13:46

Tip: Since this machine has the same CXA1145 TV-Encoder as the Sega Megadrive, you can also look for tutorials on how to add s-video on that console too.

Por tsmvp

Resident (49)

imagem de tsmvp

15-03-2020, 13:11

That said, CRT TVs are damn cheap in Brazil. LOL!
So why not get a TV and add RGB to the TV? You will then be able to use anything through the RGB port what will certainly give you a much better picture.
Bem melhor do que S-Video.


Por sd_snatcher

Prophet (3502)

imagem de sd_snatcher

15-03-2020, 14:57

Sadly, not all TVs have an easy way to add RGB. Yes, you can always bypass everything and inject on the neck PCB, but this has a plethora of problems of its own, including signal level, insulation, autocalibration and even the loss of brightness/contrast controls.

I have a Sony Trinitron 14" (Sony KV-1450B), a model that looks very similar to the one featured on the famous Sony HB-F1XV ad on MSX-Magazine. But that whole family based on the CXA1871S Jungle chip is a nightmare to add RGB input. Even if you try to bypass and go for the neck PCB, the main PCB senses it and shuts down the CRT as a protection.

It's somewhat possible to add component-video input to that family of TVs, but it requires a huge surgery and you'll have to compensate for the luma/chroma delay of the TV's Jungle Chip. Definitely not for the faint of the heart.

I ended up choosing a compromise: It's much easier to add s-video to this family. The 14" Trinitron model requires an extra PCB with a analog multiplexer that was only present on the bigger siblings, but once it's added it works like a charm. Since the original contrast and image quality of this TV is superb, the s-video input achieved impressive results.

(Note: ironically, it's very easy to add digital RGB input to this family. But that would only be relevant for PC-88 and FM-7 owners)

In a nutshell, buying a CRT to mod it to add RGB inputs is a lottery. I would advice to google for models that are easy to mod.