'''<big>Bought a 464 or 6128 from eBay ? Broken or not working right ? Read onfor repair tips and where to buy spares..</big>'''
The last versions of the 464/6128 (1989/90) had a more modern 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 you could not recouped back via eBay, should the board be duffbeyond repair.
Firstly make sure you are properly earthed with a £2 anti static strap that is plugged into a proper mains socket (via the earth pin, obviously..) Then get setup on a nice clear desk with a good lamp, preferably one of those with a large magnifying glass to look through,
like jewellers use. Then get yourself an Antex 25w or 15w soldering iron with a smallish soldering tip on the end. You will also need a
stand for it with a sponge for wiping off crud from the tip. A simple de-solder pump with plastic tip is also needed. Finally get some good quality, fine nosed wire cutters. Maplin sell all of these, as do eBay.
Now you are ready. Clean of any dust from the chip in question and carefully snip the legs off the chip at the their highest point, closest to the chip itselfas possible. Remember that we don't care about the chip as it is duff anyway. The mainboard and its tracks are what we have to protect.
Once you have snipped all the legs, the chip will just fall off, leaving a bunch of legs or pins sticking up. Now use a pair of
suck out the solder from the holes where the pins were, ready for a chip DIP socket to be installed.
This is a slow process but be calm and methodical and you wont go wrong.Its all worth it when that Amstrad logo comes up again !