Dismantling an Amstrad PcW16

The only component which can be replaced easily on the boards is the fuse on the power board, and for this no dismantling is required; all other components are soldered directly to the boards, and most need specialised equipment and skill to replace them, assuming that a suitable spare component can be found. The floppy drive is electronically a standard but physically a special (Panasonic JU-257A966P) so a standard drive won't fit inside the machine. If a direct replacement isn't available a standard drive could be used externally using extension leads. I believe that new replacement boards and other parts are available but are expensive. An economic alternative is to use a tested secondhand unit. I can sometimes supply these; try me.

Therefore the usual reason for dismantling your PcW16 will be to completely replace one of the units of which the machine is comprised; the cathode ray tube (CRT), the power supply unit (PSU) board, the central processing unit (CPU) board, the floppy drive, or one of the small items such as the standby switch.

SAFETY
Before taking the back off the machine, switch off and leave the machine for a while so that the high voltages which remain stored in the machine's capacitors for some time can leach away through the earth pin of the mains plug, then remove the plug from the mains socket. How long is "a while"? well, at least half an hour, longer if possible. The high voltages stored are unlikely to do you serious harm unless you have a medical condition, but can be akin to the shock experienced from touching a car spark plug lead unwisely with the engine running; short and sharp but best avoided. Never fiddle inside the machine with the power on unless you know exactly what you're doing

REQUIREMENTS
The only essential tool is a Philips type screwdriver of about 5mm diameter. in addition it is good to have a folded, soft, single-colour cloth to work on to prevent scratch marks on the casing. This cloth is also invaluable when dismantling components as small items such as screws will not bounce away and be lost when dropped. You may also need a broad metal blade, such as a metal rule, a table knife, etc. to prise apart some connectors. Some methylated spirit, some kitchen paper and a soft brush will also be useful for cleaning purposes. A small container is handy for storing screws which are removed and a pencil and paper for making notes.

METHOD
At the time of writing, I have just dismantled a PcW16 completely, and these are my findings. There may be other ways to procede and some short cuts, but I believe this method is the simplest and safest.

First remove any peripherals such as mouse and keyboard. Remove 6 screws from the casing and remove the back. As you look from the rear of the machine you will see, immediately below the tube, the power supply board, and below that the CPU board. Sandwiched between them is the drive. In the following RHS means right-hand side, and LHS means left-hand side, viewed from this position.

Removing the power board

1. Remove the black earth wire from the RHS. Free red/green/blue wires from clip.
2. Gently unplug the PCB (printed circuit board) from rear of tube
3. Unplug the earth lead from this PCB and lay the PCB on the power board.
4. Remove the earth wires (one green/yellow and two black) from LHS
5. Remove two plugs from the RHS of CPU board (under power board). Prise one off with your blade, the other has a clip which should be held back during removal.
6. Remove HT lead from tube. To do this, lift the rubber disc and look under it. The lead is held in a pocket in the tube by a spring clip. Move the clip sideways to bring the two parts together then, by tilting the clip, it will come out of the pocket; no tool is needed.
7. Hold back plastic clips at either side of the power board and wriggle the power board out about an inch until the power connection plug can be easily reached and unplugged.
8. The power board can now be removed from the machine.

Removing the CPU board

1. Remove 3 screws (2 x csk and 1 x roundhead) which secure the front end of the metallised plastic shield and fold the shield back to expose the CPU board. Note that the two csk screws also secure the floppy drive.
2. Remove cables from the drive; try not to pull on the cables but hold the connectors. Note that the 4-way power connector has a clip on the underside which should be held back with a small screwdriver or similar tool.
3. Unscrew black earthing wires from side of drive.
4. Remove two holding-down screws at rear of CPU board(the LHS one secures earthing wires
5. Prise off the 3-wire connector (red/green/blue) from the stand-by switch
6. Remove CPU board.

Removing the floppy drive
If you have followed the above procedures, all that is required now is to remove 2 x csk screws from the underside of the drive. The drive can now be removed in it's cradle.

Reassembly

Reassembly is, of course a case of reversing the above procedures, but there is one point to note. However carefully you try to replace the rear cover it sometimes refuses to fit. There is a projection inside the cover that goes beneath the power board to support it, so you have to keep the board lifted a little whilst replacing the cover.

The keyboard

If the keyboard is beyond repair it can be replaced by a cheap modern keyboard with a PS2 connector. The new keyboard, particularly if it is a "Windows" type will have extra keys. Just check those which work with the PcW16 and ignore those which don't. If possible take along your faulty PcW16 keyboard and if there's a choice buy the keyboard which most resembles it. Keys can be covered with coloured labels and marked similarly to the original. Not all keyboards are suitable; if strange things start to happen, such as the mouse refusing to work or the screen freezing, then suspect your new keyboard before you start to use the Rescue Disc or take other extreme measures.

Ron King
Andover, UK
e-Mail address .........ron@king27.freeserve.co.uk

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