Sinclair ZX81, Assembly Instructions Manual, Page: 34 / 43

2 1 F E R N E Y HILL A V E N U E R E D D I T C H W O R C E S T E R S H I R E B97 4RU
TEL REDD1TCH (.0527) 61240 P R O P R I E T O R C. C. L O C K r E R
RE7.7 KEYBOARD CONSTRUCTION NOTES.
FireU check the contents of your kit, which should contain the
following:-
Quantity Description Quantity Description
1 RE77 FOB 26" Link wire
40 Keyawitchss 8" Sleeving
40 White keytops 18" 20 way ribbon cable
40 Clear key* covers 1 Legend Set
Fit sixteen short wire links a9 shown on fig 1, then fit two
long wire links which should have sleeving. Put the 40
keyawitches into place. Note that the pins in the switches are
offset from the centre, and if you try to put the switches in
the wrong way round the switch body will foul the wire links.
Having placed the switches, putt a sheet of card over them,
turn the irinted circuit board over and solder the switches.
Check that all the switches are resting firntlj; on the P.C.B.
and are straight.
Fit the 40 white keytops and push on firmly. Take the legend
set and place it on a firm card. Using a Steel rule and a
sharp knife, cut out the letters using the edge markers as
guides. You may prefer to draw faint lines and use scissors.
Using your computer or handbook as a guide, place the legends
one at a time on the keytop and push on the clear plastic top.
If you have purchased the RE77B connector solder the ribbon,
cable to it (4 of the wires are unused and may be removed).
If you do not wish to use a connector the cable may be soldered
to the PCB. The completed keyboard may now be fitted to your
2X80 or ZX81. First study the connection details for your
computer. (Fig 2 and fig 3) (More details on figs 4 and 5)
Carefully solder the ribbon cable to the computer PCB as indicated.
The ribbon cable may now be run out of the case underneath the
PJYM pack connector. Recheck all your soldering, then test your
computer and new keyboard.
Fold your keyboard cable under your ZX80/81. Push the computer
bo the back of your desk with your new keyboard in front. This
way you have no untidy twists in your cable.