Philips NMS 8220 (MSX2) - no video output via Scart

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By Hrothgar

Champion (479)

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05-03-2019, 13:53

Boot sequence of an NMS 8220:
- Scrolling logo appears and (V)RAM figures are shown for a few seconds.
- Screen turns blue.
- Beep.
If at the beep you're having the Esc key pressed, it goes to Basic, otherwise to the Designer.

By Tarnyko

Rookie (20)

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06-03-2019, 18:16

Thanks Hrothgar ! I'm pretty sure I get no beeps... but let's not panic until I get my converters (~ 7 days).

(PS Wlcracks : I could take the MSX to a home with SCART TV this weekend ; but for 3 days of delay, I won't bother so much)

By Tarnyko

Rookie (20)

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20-03-2019, 10:50

Hi folks,
You may remember my display issue ; I finally got it fixed (yay !), using the most ingenious set of components :

which gives me this wonderful :

I know, I know... I'ill invest in a direct converter/monitor at some point :P .

By Grauw

Enlighted (8084)

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20-03-2019, 11:16

Big smile

By Nprod

Resident (35)

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20-03-2019, 12:40

We must be living in a bizzaro world where finding a CRT TV is harder than getting a weird stack of video converters...

By Wlcracks

Champion (315)

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21-03-2019, 08:23

Nprod wrote:

We must be living in a bizzaro world where finding a CRT TV is harder than getting a weird stack of video converters...

Seinfeld or Superman?

By Tarnyko

Rookie (20)

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16-04-2019, 22:10

Hi folks,

You may remember my MSX SCART -> PC VGA issue display issue.
Well the solution was kinda working but imperfect (bad image). And anyway I decided to get to the bottom of it.

So basically you have this SCART (15 kHz RGB+Sync Analog) signal. Which, for Analog VGA conversion, raises 3 issues :
- it has a resolution similar to 320x240, but VGA needs 640x480 minima ;
- it has a 15 kHz frequency, but modern VGA monitors require 30 kHz (15 Khz VGA monitors used to exist, but are discontinued) ;
- it does not send the same type of "sync" beam.

So we obviously need a line/scan doubler, with VGA final output. It will upscale the definition and also generate these 30 kHz/sync things for us.
2 quality solutions are still on the market : OSSC and japanese Framemeister XRGB. They are fine but also DAMN EXPENSIVE; so let's consider we do not want to sell our house, and get a chinese GBS-8200 derivative instead.

This takes care of the "raw" video conversion, but does not handle our SCART plug, nor its audio component. Thus we'll need 2 additional parts :
- a SCART-extension-with-Jack-Audio-derivate, which will "isolate" the audio channel and let us plug our speakers.
(Warning: it is directional -you have to plug the "male" part towards the MSX)
- a SCART-to-RGB+Composite adapter, with its associated cable.

(You may be wondering, why not just grab such a cheaper cable ? Well, there is a trick here; remember this "sync" beam ? For SCART, it lives in the "composite" pins, and we do not want to send it to the GBS-8200. The "Yellow" plug on our adapter happens to be RCA Composite; we won't plug it, and it will effectively isolate the sync beam, so it does not go through any of the 3 other "R/G/B" plugs we'll use)

So here you have all the stuff. Plug this all together in the right order, power it on (GBS-8200 comes with a DC input ; so did the former HDMI/VGA converters), and you're good to go. Well ?

Well, there may still a problem (in fact, I had this VERY problem). I live in Europe and my MSX is, well, European -Philips : it outputs at a 50 Hz rate. Good PAL ! But at first my display was totally black-on-white. So was I complaining until I ran the Bubble Rain game, which forces 60 Hz at startup and... Magic ! Color everywhere !
So it happens that GBS-8200 _may_ handle 60 Hz better than 50 Hz. It depends on your batch, luck and the position of Pluto. Let's say we are paying the "price" of a cheap Chinese replacement.
But no worries, 'cause it also happens that this version of SIDplay comes with a cool utility named HZ.COM. Run it from MSX-DOS, and it will switch your VDP to 60 Hz. Go even further, put in into your AUTOEXEC.BAT ^^.

By Vampier

Prophet (2288)

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16-04-2019, 22:39

the first thing I did when my old NMS8220 arrived in the US was to get rid of the auto starting designer ROM Smile

By Pentarou

Master (187)

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16-04-2019, 23:42

Your description is a bit confusing:

Tarnyko wrote:

- a SCART-to-RGB+Composite adapter, with its associated cable

Description says it's a SCART to YUV (Component) converter, If that's the case then sync is mixed with the Y signal and it's OK for the GBS.
But if it doesn't have a conversion circuit inside, and it's just a pass trough meant for devices that already output YUV, I have to wonder how your GBS can possibly work without a sync signal.

Anyway, go here: . Add the arduino board and do the mods described. The GBS will become an amazing device instead of a temperamental crappy one.
If you add the 100 Ohm resistor to the sync you can also ditch the SCART to YUV converter and use the SCART to VGA cable from your first post.

By Tarnyko

Rookie (20)

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17-04-2019, 00:53

"Vampier" wrote:

the first thing I did when my old NMS8220 arrived in the US was to get rid of the auto starting designer ROM Smile

Haha, got tired of keeping this [Esc] key pressed each time Wink ? In fact I envisioned doing the same, but having already cleaned the insides and taken a few odds, I didn't want to risk breaking my precious MSX ^^.

"Pentarou" wrote:

Description says it's a SCART to YUV (Component) converter, If that's the case then sync is mixed with the Y signal and it's OK for the GBS.
But if it doesn't have a conversion circuit inside, and it's just a pass trough meant for devices that already output YUV, I have to wonder how your GBS can possibly work without a sync signal.

So this explains it.
There are a lot of confusing and contradictory info on glorious Internet ; some people say this sync signal isn't needed, others that it generates noise in the final picture, and now I finally learn not only that it's required, but that my converter works for a totally different reason.
Thanks for the URL, this seems to be the way to go further ! Not now though, I'm tired by all this hard work ^^.

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