Setting Up; Unpacking - Sinclair ZX81 User Manual

Chapter 1 - Setting up the ZX81
Unpack the ZX81, you will have found
1. This manual.
2. The computer. This has three jack sockets (marked 9V DC IN, EAR & MIC), one aerial socket, & an
exposed part of its circuit board where you can
plug extra equipment. It has no switches - to turn it on you just connect it to the power supply.
3. A power supply.
This converts mains electricity into the form that the ZX81 uses. If by accident you plug it into the wrong
socket in the computer you will do no damage. If you want to use your own power supply, it should give 9
volts DC at 700mA unregulated, & end in a 3.5mm jack plug with positive tip.
4. An aerial lead about 4 feet (120cm) long, which connects the computer to a television.
5. A pair of leads about a foot (30cm) long with 3.5mm jack plugs at both ends. These connect the
computer to a tape recorder.
You will also need a television - the ZX81 can work without one, but you won't be able to see what it's
doing! It must be a UHF television - if it's
not built to receive BBC2 (in the UK) then it's no good.
Later you will need a cassette recorder. This is because when you turn a ZX81 off, all the information
stored in it is permanently lost. The only way to keep it for later is by recording it on a cassette tape - you'll
see how
to do this in chapter 16. You can also buy tapes that other people have prepared, & so run their programs.
When you've got everything together (except the cassette recorder) connect them as shown on previous
page.
If your television has two aerial sockets, marked UHF & VHF, then use the UHF one.
Turn the power on, & switch on the television. You now need to tune the television in. The ZX81
operates on channel 36 UHF, & when it is first plugged in and properly tuned it gives a picture like this: