These instructions are given in good faith following the experience of performing the operation on numerous keyboards without failure, but no liability can be accepted by the author if you damage something in the process. The only tools you need are a Phillips type screwdriver, something to prise the keys off with, such as a flatbladed screwdriver with a blade about 6mm wide ( or a blunt-ended sturdy knife). You will also need some methylated spirit and some cotton wool.
If the keys of your keyboard are decidedly grubby or are sticking you should consider cleaning it. This calls for perseverance and care, rather than skill, but should not be undertaken lightly. Allow a couple of hours at least if you are going to give it the full treatment. The following describes how to strip it right down, but you don't have to do that unless, after taking off the keys, you find that dust or fluff has got right into the innards. Steps 5,6 and 7 can thus be ignored. Removing and cleaning the keys is often all that is required, together with removing dust with a soft brush.
Dismantling
1) Turn the keyboard upside down on to a soft cloth and remove 6 screws which
hold the case together.
2) Turn the keyboard right way up and remove the upper casing.
3) Place the tip of the flat-bladed screwdriver (or knife) under the edge of one of the upper keys, perhaps the [STOP] key and turn it gently. The key will pop off, revealing a large spring. Place the key upside down and place the spring over the shank of the key. Don't attempt to remove the small spring in the centre of the shank.
4) Repeat this with the other keys in turn except for the space bar, the left-hand side [SHIFT] key and the [RETURN] key, and place them in relative positions to the first key. (If you get them out of order you had better have a good memory or a user manual or you'll have problems). Those keys mentioned are secured differently from the others and if you prise them off you will at least give yourself more work and at worst do damage.
5) Turn the keyboard upside down again and lift off the plastic casing. Remove the two screws which hold the printed circuit board, unplug the board and lift it off. Put it in a safe place.
6) Starting one end disengage the clips which hold the membrane assembly together until the components can be separated. Remove the membrane and keep it in a safe place.
7) Wipe the membrane with a soft cloth or cotton wool to remove any dust. Bad marks can be removed with cotton wool dampened with meths. but be very gentle.
8) Clean the plastic key holder and the attached keys with meths, also the metal base plate. Try not to dislodge the small red LED. If you do, remember to replace it before reassembly.
9) Reassemble the keyholder, membrane and metal base plate; replace the printed circuit board and plug in the membrane connectors.
10) Wash the upper and lower plastic cases in warm water with washing up liquid. Dry thoroughly then put the membrane assembly in place.
11) Remove a spring from its key and place it in position on the membrane assembly. Wipe the key clean with a piece of cotton wool damped with meths then click it in its correct position on the keyboard. Continue until all the keys have been reassembled in their respective positions. If you are unsure, check the correct position with one of the illustrations in the user manual.
12) Replace the upper casing, turn the keyboard over and secure with the 6 screws. Finally clean the connecting cable with meths.
Your keyboard should now be thoroughly cleaned and ready for many more weeks, months or years of work before requiring further attention.
Whilst the keys are out the opportunity can be taken to remark the lettering if necessary. This can be done after cleaning with lettering transfers (2.5mm and 5.5mm are appropriate sizes) or with waterproof ink. The refurbished letters must be protected; preferably with a cellulose spray or with clear nail varnish.
Ron King
e-Mail address...........ron@king27.freeserve.co.uk