RGB>SCART>HDMI issue.

Hey all,

First post for me and already hassling for advice..

I have built an RGB to SCART based on Stedy's schematic and am using it to connect to one of the Chinese SCART to HDMI converter/scalers.

It does work quite well but has a quirk...

When the Amiga (500) is first switched on the device displays "CVBS" in the top corner of the screen but nothing else. (black)

Purely by accident I found that if I briefly short pin 16 on the SCART plug to earth I get a display.
The display remains on and works fine until the PC is switched off, then I have to repeat the process...

I have around 2.3V on pin 16.

Any thoughts on how to solve this?

Cheers
Ash

[johnim]

have a look here about pin 16 blanking

http://www.idiots.org.uk/vga_rgb_scart/index.html

and here

http://www.sega-16.com/forum/showthr...-for-megadrive

it says here a 150ohm resistor needs to be pin16 to 22

http://wiki.classicamiga.com/Amiga_RGB_to_Scart_lead

Thanks, but I understand the mechanism used for switching RGB - I have 2.4v on pin 16.

The problem is that even with the correct voltage the HDMI converter is not selecting RGB mode.

[Ed Cruse]

Originally Posted by ashhhhh

Thanks, but I understand the mechanism used for switching RGB - I have 2.4v on pin 16.

The problem is that even with the correct voltage the HDMI converter is not selecting RGB mode.

I'm just guessing here, but maybe pin 22 is ground and the 150 ohm resistor is used to pull pin 16 to ground. From what you said earlier about shorting pin 16 to ground it sounds like a low is needed, 2.4v isn't what I would call a good low.

[Stedy]

Hi,

A wild idea, try disconnecting pin 8 of the SCART lead. Perhaps the cheapo device is having trouble with the AV select input.

When you short pin 16 of the SCART to ground, does tyhe adaptor display an RGB image or is it using composite?

Try an interlaced screenmode on your Amiga. The Amiga's video output is 288p, not 576i.

Ian

I'm just guessing here, but maybe pin 22 is ground and the 150 ohm resistor is used to pull pin 16 to ground. From what you said earlier about shorting pin 16 to ground it sounds like a low is needed, 2.4v isn't what I would call a good low.

No pin 22 is 12V and im not using it at all.
I'm using Amiga pin 23 which is 5V to provide power to SCART pin 16.
2.4 is within tolerances specified on the diagram, can go lower I guess though.

Hi,

A wild idea, try disconnecting pin 8 of the SCART lead. Perhaps the cheapo device is having trouble with the AV select input.

When you short pin 16 of the SCART to ground, does tyhe adaptor display an RGB image or is it using composite?

Try an interlaced screenmode on your Amiga. The Amiga's video output is 288p, not 576i.

Ian

Ahh pin 8 already disconnected, I figured it wouldn't be needed.

When the Amiga is switched on the device says "CVBS" (Composite)
When I short the pin and the displays comes on the device does not give a notification that it has changed modes.

(note, I don't leave the pin shorted - this causes a blank display. It is just a brief short and remove)

How do I set an interlaced mode at startup?

Thanks to everyone for the assistance.

Ash

Urrgh...waste of money.
I have bought a CSY-2100 and it works great.

Do NOT waste your money on the HDMI option.

[Stedy]

@ashhhhh

What was the model number of the cheap HDMI adaptor that did not work?
I only ask so that others know not to purchase the same model.

Ian

Yeah it was one of these - http://www.ebay.com.au/itm/260970656...ht_4390wt_1139

To be fair it did work, just not without the shorting trick...

I have used the same cable with the CSY-2100 and had no issues, so definitely a problem with that device or its design.