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

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.

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 .

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

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 ^^.

Your description is a bit confusing:

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.