Now carefully remove the case.. Be '''VERY''' careful with any keyboard membranes. You '''CANNOT''' buy these anymore.
eBay is The best source for spare chips and other replacement components that I have found, btw.
to buy online if you look long enough.
6: Check for damage to the tracks at the edges of the board. these can often be fixed with a few wires soldered to nearby points, to re-route the voltage around broken tracksand back where it was supposed to go.
Capacitors and resistors are too cheap to mention. FYI: buying a bag of 5 is frequently little more expensive than buying just
1 or 2. Then you have spares as well. 85c rated parts are fine. 105c is also fine but excessive and a waste of money.
The Z80 cpu can be easily replaced for as little as £3 new, as can the 8255AP-5 interface chip and the AY-3-8912 audio chip.
The CRT controller UM6845R is about £4.50. They are all actually made by several different manufacturers, with very slightly differing model numbers for what is actually the same product. So shop around first and check the specs/pinouts before buying one that is over priced. Look Compare at the chip model numbers on the cpc wiki mainboard images to check what will and wont work.For example, the same CRT chip is listed under three sets of models numbers and manufacturers. Memory (DRAM) is quite easy to source from eBay as there are a surprising number of UK suppliers who have stocks of 4164 or 4264 dram chips
The Gate Arrays, either Amstrad 40007 or 40010, are the only expensive parts at between £8 and £15.
It's a suppliers market for these unfortunately.. The two models NOT interchangeable as they have different pinouts, even though some boards made potential allowance for either chip in their designs.
For the floppy control circuitry, the NEC 765 controller can still be acquired but the SEC9420C buffer is a hard one to track down. Luckily these are virtually never needed as you are likely to have replaced everything else before getting round to that anyway.
The last models of 464/6128 (1989/90) had an integrated SMD chip that removed the need for a gate array. They were known as the "cost-down" boards. These chips physically cannot be swapped out and so would render any such board as scrap, if it turned out to be the SMD chip. Avoid any major expenditure on these boards, that cannot be recouped via eBay anyway.