Zx Spectrum 128k +2 RGB - SCART

[elmanoduarte]

Hi all...

Here i m again... just received a new RGB to SCART to connect the spectrum to a TV by the Scart connector.
Its seams to work , the sound from the keyboard is fine, but the image from the spectrum in the TV screen its so DARK its almost impossibel to see the window with the selector from the spectrum +2,, i can see the Load, Calculator, the 128k mod and 48k mod,,, but soo Dark...realy Dark...

Theres anything it could be done to make it work?
Mabe not corect pinout. However in ebay the seller said its rite for my Grey Version... but something its wrong.

Any help Please??

Regards, Duarte

[1024MAK]

Okay, a photo of what you see on the TV would help…

I assume this is a modern or relatively modern TV? That is a LCD, “LED”, or other TV rather than a old CRT type?

So first of all, does the TV have more than one SCART socket? Normally if more than one, only one of the two is RGB capable.

Modern TVs have automatic function switching. None of the ZX Spectrum models sold in the U.K. is fully compatible with the modern SCART function switching.

Is there a menu or other user control to manually select RGB input on the VA input that is used for the SCART input. A SCART input by default is composite video. But some can also use component video as well.

The next option is to change some of the wiring in the RGB SCART cable.

Try the following:

• Remove any wiring or any capacitor connecting between pins 16 and 18 on the SCART plug and remove any existing wiring to pin 16. Do take note of how it was wired up before you di this though.
• Use a 12V regulated power supply and wire the positive to the SCART plug pin 8. This 12V on pin 8 selects TV on and 4:3 aspect ratio.
• Connect a resistor between SCART plug pin 8 and pin 16. The value is not critical as long as it’s between 330Ω and 560Ω. The aim is to drop the voltage to between 1V and 3V. The resistor acts as a divider when combined with the 75 resistor in the TV.
• Wire the 0V / common / negative to SCART plug pin 18.
• If you don’t have a suitable 12V regulated power supply, a new 9V alkaline battery (e.g. this size: PP3, MN1604, 6LR61, 6AM6, Rayovac A1604, Energier 522, Varta 4922) may work for testing purposes.

Mark

[elmanoduarte]

Hi..many thanks for answer,,here is some pictures.

[elmanoduarte]

The scart.. inside pins..

[elmanoduarte]

Another,

[elmanoduarte]

...

[elmanoduarte]

...

[elmanoduarte]

It looks like the brightness its all Dark.
After asked to the last owner, he said he have used an power supply 9v with inverted polarity.

Now... with this NEW.. dont know if its just a pins scart case!!

Mabe some component is working bad because the wrong polarity. Now i m using a rite 9v with 5 amp. Dc..should do enought.

In the dark its hard,, but i can write Basic comands, and the spectrum works normaly. Sound is normal to.

For me put this old Spectrum working after almost 40 years, it will be ...FANTASTIC...
Please help..

Best regards for all
Duarte

[elmanoduarte]

I have made a conection directly from RGB spectrum putbto an RCA Vídeo TV.
I think i used pin 7 and 4, not shore,, shat is shore is it show good whit screen with the Amastradblack letters,, a little more and it will be great ,, so,, mabe it can be solved for who have aknowlage. I dint

[1024MAK]

Yes, so it definitely looks like your TV has automatic function switching. The reason that your TV is not correctly showing the picture from the ZX Spectrum, is due to it not being in RGB input mode.

I recommend changing some of the wiring in the RGB SCART cable inside the SCART plug.

• Remove the capacitor connecting between pins 16 and 18 on the SCART plug and remove any existing wiring to pin 16. Do take note of how it was wired up before you do this.
• Use a 12V regulated power supply and wire the positive (+) to the SCART plug pin 8. This 12V on pin 8 selects TV on and 4:3 aspect ratio.
• Connect a resistor between SCART plug pin 8 and pin 16. The value is not critical as long as it’s between 330Ω and 560Ω. The aim is to drop the voltage to between 1V and 3V. The resistor acts as a divider when combined with the 75 resistor in the TV.
• Wire the 0V / common / negative (-) to SCART plug pin 18. If there is already a wire on pin 18, just add on to the existing solder joint.
• If you don’t have a suitable 12V regulated power supply, a new 9V alkaline battery (e.g. this size: PP3, MN1604, 6LR61, 6AM6, Rayovac A1604, Energier 522, Varta 4922) may work for testing purposes.

The English Wikipedia article on SCART is here. It includes a diagram showing the pin numbering.

Mark