The TV Display
Old Televisions Were Analogue and Expensive
Another common problem is that when the Spectrum was brought out in 1982, it was common for home computers (called “microcomputers” back then) to use the domestic TV to output their display, and to not use monitors. This was a big cost saving. After all, the Spectrum was made for a budget market to popularise and democratise computing.
And in 1982, it was common for there to be only one TV in a house or flat – or if you were lucky, perhaps one main TV for the family room and a portable TV that might even have been black and white. Yes, really, TVs were black and white before colour.
TVs in 1982 used an analogue radio wave signal, which was normal for broadcasting TV in those days. There was no digital TV signal. And the TVs were cathode ray tube (CRT) designs, which are high voltage and very heavy, as well as being dangerous in the wrong hands.
So inside the Spectrum, there is a modulator box that converts the Spectrum display to Channel 36 UHF (Ultra High Frequency).
Why Is The Spectrum Display A Problem?
Now in modern times, this is a problem because modern TV designs do not use CRTs. And the analogue TV signal has been replaced with a digital TV signal. Old tech like 1980s computers need to be looked after to make them work with new TVs.
If you have an old TV, this is not such a problem. But CRTs are getting old and can cause problems with reliability and safety. As already mentioned, they are high voltage and high current and can produce big and dangerous problems if not looked after properly by someone qualified and experienced. Even one that seems OK can go wrong without warning.
Keeping It “Pure” – Using the Analogue Signal?
You might want to keep your Spectrum “pure” and try to keep it as close to the original design. You can. It is your Spectrum, so you can do what you want.
Some modern TVs allow you to easily tune to analogue signals. Others have a complicated menu system to navigate. And other TVs don’t allow you to even tune in to analogue at all. Sorry, but I do not provide support for all TVs, as there are so many. But I can modify your Spectrum to make it more compatible with modern TVs.
Modern TVs expect certain characteristics of the signal from the old computers and the computers just cannot live up to modern expectations.
If you want to maximise the chances of the analogue RF signal working, and “future proof” your Spectrum, then it is wise to change the electrolytic capacitors to new ones. PopeyMon can do this for you.
Better To Use The Composite Video?
So while you can do it “the old way”, I recommend that you are more likely to get a better picture if you use the composite video signal that was always generated by the Spectrum and then converted by the RF modulator. You just ignore the RF output and by-pass it.
The composite video modification is another service that I provide at PopeyMon. You can buy it from the shop by clicking here.
Please check that you have a composite video input on your TV before ordering this service. The video is the yellow-marked connector of three connectors that are yellow, red and white. The red and white are stereo audio signals.