Powergraph V9990 SCART cable

By joy_33

Rookie (20)

joy_33's picture

19-10-2020, 18:23

Hi, gentlemen, I need advice.
I bought a V9990 card for MSX (https://www.msx.org/wiki/Tecnobytes_V9990_Powergraph)
And I need to connect a cable so I can use the RGB input on my TV or monitor.

The connection of this card is as follows.

Powergraph Light uses a different pinout, meant to carry the signals needed by the breakout board for CVBS and S-Video connectors. The connector used is a DE-15 subminiature like V2's.

V9990 has the following connection:

Pin Signal
1 R out
2 G out
3 B out
4 S-Video C
5 GND
6 GND
7 GND
8 GND
9 + 5VDC
10 GND
11 Not Connected
12 S-Video Y
13 H_Sync
14 Not Connected
15 Composite Video

I'm trying to connect it to a SCART connector

1 R out - SCART - 15
2 G out - SCART - 11
3 B out - SCART - 7
4 S-Video C - SCART - not connected
5 GND - SCART - GND
6 GND - SCART - GND
7 GND - SCART - GND
8 GND - SCART - GND
9 + 5VDC - SCART not connected
10 GND - SCART - GND
11 Not Connected not connected
12 S-Video Y - SCART not connected
13 H_Sync - SCART - 20
14 Not Connected - SCART not connected
15 Composite Video - SCART not connected

I connected unconnected GND from the card to SCART to GND PINs, GND from the connector package on the card is connected to GND package at SCART.

When connected, there is some hint of the image, but slanting bars constantly appear and the image scrolls up.

It's about connecting pin 13 on the card, does it really have to come to pin 20 on SCART? WIKI introduces pin 20 - RGB-sync input, composite signal input, brightness input, but where else to connect it?

I will add that an NTSC signal is coming from the card, if it affects the connection?

What am I doing wrong ?

Guess the TV will switch to RGB by itself? When a very lousy picture is displayed, or do you need the 1-3V pin 16 on the SCART?

I apologize for my English, translates google translate.

Thank you for any advice.

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By sdsnatcher73

Paragon (1198)

sdsnatcher73's picture

19-10-2020, 19:05

I would try connecting composite video from V9990 to SCART 20 and see if your image stabilizes, my guess RGB sync is really more HV sync (but no expert either), anyway composite video is commonly used for syncing RGB, albeitnot as clean as a true sync and you may get jailbars (still better than rolling picture).

By Pentarou

Champion (290)

Pentarou's picture

19-10-2020, 19:42

Don't use H_Sync, use instead:

15 Composite Video - SCART 20
or
12 S-Video Y - SCART 20

joy_33 wrote:

Guess the TV will switch to RGB by itself? When a very lousy picture is displayed, or do you need the 1-3V pin 16 on the SCART?

No, TV will need a voltage to swicth to RGB, connect:
9 + 5VDC - SCART 8 (Enable SCART)
and
9 + 5VDC -- 100 Ohm resistor -- 16 SCART RGB (Blanking) enable

Need both connections

By joy_33

Rookie (20)

joy_33's picture

19-10-2020, 21:11

Thank you for the advice .....

15 Composite Video - SCART 20 - the picture jumps but is of poor quality
12 S-Video Y - SCART 20 - also the image jumps are of poor quality and only black and white

By joy_33

Rookie (20)

joy_33's picture

19-10-2020, 21:38

I took the liberty of making a video with the settings of
12 S-Video Y - SCART 20 - also the picture jumps are of poor quality and still only black and white
cable connection

https://youtu.be/q1e1X9ofLPo

By Pentarou

Champion (290)

Pentarou's picture

20-10-2020, 18:50

If the picture is black and white it means that you are NOT in RGB mode, you NEED the connection on pin 16 of the SCART.

By Mumbly

Expert (69)

Mumbly's picture

21-10-2020, 21:43

Still the issue? I have the same vdp, from tecnobyte, The one with the 15 pins
vga like Connector, I made myself the vga to scart cable and it works fine on every
Tv/monitor. Do you want me to find back my schemas ?

By Mumbly

Expert (69)

Mumbly's picture

21-10-2020, 21:54

Just figuring out that you have the light version, mine is the v2 version
Meaning as mentionned, another pin out. Sorry