It is usually more economic to obtain parts from machines bought at car boot sales, local auctions, or through advertising locally. Most of the older machines can be obtained quite cheaply, particularly the PCW8256; there must be thousands still in garages and lofts which the owner would be prepared sell at a reasonable price or even give away in return for a donation to charity. If you have to pay serious money make sure that you know who you're buying from, try it first and ask for some sort of warranty.
Another possibility is to look in the classified pages of MicroMart and PC Mart or even advertise for parts yourself. PCW specific magazines also carry ads. for parts, together with details of firms which support the PCW range.
If you have a PCW problem you first need to diagnose the cause and a look at the diagnosis file in the repairs section of this site will probably help. Having decided on which part is faulty the search for a replacement or repair can begin.
The dot matrix printer
There are two basic types of dot matrix printer for
the PCW8256/8512. One has a plug-in printing head which has "HOT" moulded on
the top, and the other has a silvered paper label also with a heat warning.
The latter is sometimes called the membrane type. Within these two basic types
there are many minor variations which make finding some spares for a particular
printer hazardous. Don't assume that because two printers look the same that
they are the same. Check carefully. Both types of printer can be used with either
the PCW8256 and PCW8512; the only difference is in the labelling. You can sometimes
buy a working printer head to replace a broken one but make sure it is the correct
type. It is often cheaper in the long run to buy a good, working secondhand
printer complete.
3" drives
New belts are available with fitting instructions for around £4, or at a cheaper
rate for two or more. However John King is currently providing belts for £1 each including postage. Go to his website from my weblinks page for details; you can print out fitting instructions from this website, you won't get better! Avoid buying "rejuvenating kits" for around £15, which only consist of a belt and a little head cleaner. If the belt won't cure the
drive problem, no amount of head cleaner will! See the repairs section of this
site.
The CPU board
The only easily replaceable parts on the CPU board are the Z80a CPU itself,
which can be bought new from specialist Electronic suppliers such as Maplins
and the memory chips which are harder to find. Otherwise it is more economic
to use a working second-hand board, preferably with the full complement of memory(512K).
The Power board
The power board is common to both models. It uses the "switched mode" circuitry
which is difficult to diagnose and repair, even for a professional. As with
the CPU board, it is better to find a complete working board but make sure that
you get the correct type. Most boards have a 5-way large connector and a small
DIP switch at the centre of the board for changing the memory circuitry, but
some older machines had a 4-pin plug and wire links. If you must try a repair,
voltage regulator chips are available from electronic suppliers. The board uses
the 7805, 7812 and 7824 chips for 5, 12 and 24 Volt regulation respectively.
Make sure that you get the one amp version. Other parts such as capacitors,
resistors and diodes are, of course, available but be sure to get an exact replacement
because of the danger of overloading and fire.
The Cathode Ray tube
This is not difficult to replace with a good second-hand unit. Look at the replacement
screen from several angles to make sure that it isn't "burned", usually with
the management screen of Locoscript. I haven't tried it but I'm told that a
white screen from a PCW9512 etc. can also be used as a replacement but you'll
have to reverse the CRT deflection yoke. That sounds great fun. Might try it
myself.
Keyboard
If your keyboard has failed see the repairs section
for help, otherwise a good replacement keyboard should be easy to find.
Daisywheel Printer
The most common spare needed for the daisywheel printer
is a replacement "armature" which fractures after a lot of use (See the repairs
section on this site) These are available new at a price of around £6. When
buying a replacement ribbon, make sure that it is compatible with the printer.
There are some carbon type ribbons on the market from reputable suppliers which
break up and fail to print much at all. Try to find ribbons which specifically
mention the PCW9512 or PcW9512+. Ribbons marked Amstrad are OK. If in doubt
get a fabric ribbon.
CPU and Power boards
These are mostly standard, but there are some machines which are known as German
machines which have a different CPU and Power board. The difference can be seen
from the back of the machine. The expansion port of the standard machine is
simply a tongue which protrudes from the CPU board, whereas the German version
has a Centronics type connector. It is possible to mix the boards if necessary
but you may have to do some butchery on the rear case around the expansion port.
Unfortunately all the chips on the PCW9512 CPU board are soldered in, including the CPU itself, the Z80a, and all the memory chips. If you want to replace them the best way is to cut off the legs of the offending chip, remove each leg separately by melting the solder and pulling it out with pliers. Don't replace the chip directly but solder in a socket into which the chip can be inserted.
Unless you are a whizz at repairing PC boards it is more economic to replace with a tested board.
The dot matrix printer of the PcW9256 is a streamlined version of the printer of the PCW8256/8512 but the cable connection is different so they're not interchangeable.
Ron King
Email .........ron@king27.freeserve.co.uk