Composite Video
Modification
On the WoS forum recently there has been quite a lot of talk regarding the best way to use a Spectrum with a modern TV, or ways to improve the quality of the picture. There are several ways to do this, including SCART but I believe that by far the simplest method is to use composite video.
After seeing many designs and listening to a lot of ideas by some very clever people, I decided I wanted something simple and effective rather than cumbersome and complicated. The point is, the Spectrum already produces a perfectly useable CV signal that doesn't actually need to be processed. So, after building and testing a small buffer amplifier on breadboard and then producing a custom designed PCB, this project was born.
The Astec UM1233 modulator, as used in many 80's 8 bit computers
Open up the modulator case and you'll see a circuit board. You need to remove this board
Once you've removed the old board, you need to prepare the modulator shell to accept the new CV board.
Start with enlarging the holes already present in the plastic piece, and then drill out the small bit of rubbish where the old power wire used to run
Next step is to fit the new CV board inside the newly modified modulator shell
Like so...
Time to clean out the mounting holes left when you removed the old modulator.
Trim and prepare the wires from the CV board ready to mount and solder into place
Like this
Your Spectrum should now look something like this
any questions? Email address on home page.