FM Towns II Video Output Questions

Started by cawley1, March 22, 2019, 07:24:16 PM

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cawley1

Guys,
I get from my last post that it's quiet on here these days, even so, hopefully someone can offer some advice...

I have two FM Towns computers - A Fresh-TV (486 SX-33) and a Fresh-FT (486 DX4-100). These two systems are very similar, but in terms of video output have one difference. The Fresh-TV has a 15-Pin port labelled Analogue RGB and the Fresh-FT has a VGA port, also labelled Analogue RGB (I guess they used the same case mold).

Before getting these, I had assumed they would output (and switch) 15kHz and 31kHz video out the same port, like my X68000, and I would need a multi-sync monitor for this. This is where my assumption was proved incorrect. The Fresh-FT is the one I use mainly, and this only outputs a 31kHz image via a VGA monitor. It never displays 15kHz. I then figured that surely the Fresh-TV would do this, as it has the 15-Pin RGB port, but having made a cable up and plugging in my multi-sync monitor to that one, it also only outputs at 31kHz.

So, I am assuming this is because *all* FM Towns II (or at least the beige coloured ones) only output at 31kHz, and conversion for the older games is done internally. I know that on the Ving ports, if I select a different video mode in the options screen, it does not cause the monitor to try and switch mode (on New Zealands Story, LORES puts the image in a screen size like that of a Game Gear, and VIDEO makes the picture appear slightly blurry).

My basic question is this - How can I get 'real' RGB output (with scanlines!) on my FM Towns II computer? Is it possible if I source one of the video cards FMT-412A, FMT-412B or FMT-418, which all have RGB posts (along with S-Video/Composite) or do I have to get a card for the older system - the FMT-411 (would this even work on a model II?)

Don't get me wrong, playing Tatsujin Ou and the like on a Sony Trinitron CRT VGA monitor is nice, but it looks more like an emulated game, with no scanlines!

Anyone able to help me out with this one?
Thanks,
Paul

parodius

SuperDeadite already replied to most of your questions here but I can also suggest to use a scanline generator such as the SLG3000, works great on my Towns HB.

sampson

#2
Your assumption is incorrect.

The first II models only supported up to 24khz

Once the beige came around 24khz was upscaled to 31khz however 15khz was not

Fresh fixed this by forcing all signals to upscale to 31khz

If you want to all to upscale you must edit TBIOS.INI and change the very last line to /S

Edit: there's also a program on vector named scanconv that will do this as well so you do not need to enable the flag - https://www.vector.co.jp/soft/dos/edu/se038307.html

Outside of this for scanlines you need some external device as the computer always had a pc monitor display that didn't have any sort of scan lines. There's also a box that you can get that takes the RGB from a towns pc and outputs to s-video like the Marty and has the same soft switch button as well.

hyrulebr

Fresh-FT Owner here!

You should use the video card as Superdeadite told you in Shmups forum.  And if you use a monitor with VGA (HD15) connector you will need a proper adapter. I got a x68000 adapter and have to modify it to work (after Superdeadite help  :)).

"On a Fresh series, H and V Sync are on pins 14 and 15, just like NEC/Sharp. But on old Towns and that video card, pins 14 and 15 are not connected. It outputs CSync on Pin 7. Later Towns monitors are actually wired for both."