Have 3 Spectrums. 128K Toastrack and two +2 (Grey) When try to use the RGB to Scart I get a poor image on the Toastrack which blacks out for about 1 second every 10-15 seconds. The two +2 give a decent image with a ghost image to the right and also have the same blackout problem.
The cable I got was marked up as being for the 128K and +2 (Grey).
The Toastrack has poor RF output, one +2 has decent RF output with a ghost image to oneside and the other +2 has no RF output.
Know the toastrack will need recaping at some point. As have owned this from New and only took it out of storage recently.
Both +2 will need recaping and one needs a replacement keyboard membrane.
RGB to Scart causing screen Blackouts
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Ast A. Moore
- Rick Dangerous
- Posts: 2641
- Joined: Mon Nov 13, 2017 3:16 pm
Re: RGB to Scart causing screen Blackouts
What TV are you hooking up your Spectrums to? Is it a newer digital flatscreen TV or an older CRT TV?
Generally, the Toastrack or the +2 don’t require recapping. The video signals are generated by the ULA and are fed directly (via 68-Ohm series resistors) to the DIN socket.
From your description, it appears your TV is using not the RGB signal, but rather the composite video signal (that would explain the ghosting). It is, therefore, possible that your TV defaults to composite video (because the blanking signal is not present in the SCART connector). Some modern (digital) TVs don’t play ball with the Spectrum’s composite signal, which is slightly out of spec, so they lose synchronization.
See if you can manually switch your TV to accept an RGB signal. If that’s not an option, you’ll have to rig a simple circuit that would feed around 1–3V into Pin 16 of the SCART connector on your TV. That should force the TV to switch to RGB mode. In a pinch, you can use a battery for that, but it won’t last long. Alternatively, you can use an external power supply, or, indeed, obtain the necessary voltage from the RS232 or Keypad socket (that’s 12V, so you’ll need to built a simple voltage divider). Additionally, 5V, 9V, and 12V are available on the edge connector.
Generally, the Toastrack or the +2 don’t require recapping. The video signals are generated by the ULA and are fed directly (via 68-Ohm series resistors) to the DIN socket.
From your description, it appears your TV is using not the RGB signal, but rather the composite video signal (that would explain the ghosting). It is, therefore, possible that your TV defaults to composite video (because the blanking signal is not present in the SCART connector). Some modern (digital) TVs don’t play ball with the Spectrum’s composite signal, which is slightly out of spec, so they lose synchronization.
See if you can manually switch your TV to accept an RGB signal. If that’s not an option, you’ll have to rig a simple circuit that would feed around 1–3V into Pin 16 of the SCART connector on your TV. That should force the TV to switch to RGB mode. In a pinch, you can use a battery for that, but it won’t last long. Alternatively, you can use an external power supply, or, indeed, obtain the necessary voltage from the RS232 or Keypad socket (that’s 12V, so you’ll need to built a simple voltage divider). Additionally, 5V, 9V, and 12V are available on the edge connector.
Every man should plant a tree, build a house, and write a ZX Spectrum game.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Re: RGB to Scart causing screen Blackouts
Yes it is a Hitachi flatscreen lcd TV. Just have option of Scart and Scart-S.
Re: RGB to Scart causing screen Blackouts
Hi
Probably the same thing hapened to me. Two Toastrack that I own used to behave like this.
Try this mod:
https://www.retrocomputershack.com/Tech ... index.html
Just remember that this modification will disconnect the composite video signal from output connnector and You will be able to use only the rgb out.
Probably the same thing hapened to me. Two Toastrack that I own used to behave like this.
Try this mod:
https://www.retrocomputershack.com/Tech ... index.html
Just remember that this modification will disconnect the composite video signal from output connnector and You will be able to use only the rgb out.
Re: RGB to Scart causing screen Blackouts
Purchased a Scart lead from Retro Computer Shack and that works.
Did not fancy trying to do the modification as been over 30 years since last played about with a soldering iron.
Did not fancy trying to do the modification as been over 30 years since last played about with a soldering iron.
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Ast A. Moore
- Rick Dangerous
- Posts: 2641
- Joined: Mon Nov 13, 2017 3:16 pm
Re: RGB to Scart causing screen Blackouts
Glad it worked out for you at the end. Thanks for letting us know!
Every man should plant a tree, build a house, and write a ZX Spectrum game.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.
Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.