User:Deriss - Revision history

Deriss at 17:08, 4 April 2017

2017-04-04T17:08:49Z

Deriss at 17:03, 4 April 2017

2017-04-04T17:03:11Z

← Older revision		Revision as of 17:03, 4 April 2017
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	3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked		3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked
	and damaged one. Remember to replace any capacitor with a product of equal or higher voltage rating.		and damaged one. Remember to replace any capacitor with a product of equal or higher voltage rating.
	Equivalent ones are nowadays frequently physically much smaller than the 1980's originals. So don't be surprised.		Equivalent ones are nowadays frequently physically much smaller than the 1980's originals. So don't be surprised at that.

	4: ~~examine~~ all resistors for signs or damage or discolouration. ~~check~~ resistance with multi meter and replace as needed.		4: Examine all resistors for signs or damage or discolouration. Check resistance with a basic multi meter and replace
			as needed.

	5: Examine all the chips for any corrosion, damage or discolouration. Virtually all the components are still available		5: Examine all the chips for any corrosion, damage or discolouration. Virtually all the components are still available
	to buy online if you ~~look long enough~~.		to buy online if you search thoroughly.

	6: Check for damage to the tracks at the edges of the board. these can often be fixed with a few wires soldered to		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 tracks and back where it was supposed to go.		nearby points, to re-route the voltage around broken tracks and back where it was supposed to go. Remember to use wires
			that are the equivalent thickness or greater, of the broken track.


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	The CRT controller UM6845R is about £4.50. They are all made by several different manufacturers, with very slightly		The CRT controller UM6845R is about £4.50. They are all 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		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. Compare at the ~~chip~~ model numbers on the ~~cpc wiki mainboard images~~ to ~~check~~ what will and wont work.		that is over priced. Compare the model numbers printed on the chips on these boards: '''''http://www.cpcwiki.eu/index.php/Mainboard_Versions'''''
	For example, the same CRT chip is ~~listed under~~ three ~~sets of models numbers and~~ manufacturers.		to see what will and wont work. For example, the same CRT chip is made by three different manufacturers.

	~~Memory~~ (~~DRAM~~) is ~~quite~~ easy to source from eBay as there are a surprising number of UK suppliers who have stocks of		1980s DRAM (that makes your 64k memory banks) is surprisingly easy to source from eBay as there are a surprising number of UK
	4164 or 4264 dram chips		suppliers who still have stocks of authentic 4164, 4264 and 3764 dram chips. When changing the memory, change the four 74LS153
			chips as well. These support the memory operation and so may have also been damaged. Don't forget to buy your 16pin DIP sockets
			as well. We don't solder in chips.. Sockets are far easier.

			Do not buy from microchips anywhere except the UK, US or Germany. There are too many eastern European and Chinese fakes around to
			be worth the minor savings.

	The Gate Arrays, either Amstrad 40007 or 40010, are the only expensive parts at between £8 and £15.		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		It's a suppliers market for these unfortunately.. Look at eBay in France or Germany too, as they were big CPC markets back in the day.
	~~pinouts, even though~~ some boards made potential allowance for either chip in their designs.		( My last 40010 chip came from southern Germany). The two chips are NOT interchangeable btw, as they have different pinouts. Although
			some boards made potential allowance for either chip in their designs, only one type is ever used.

			For the floppy control circuitry, the NEC 765 floppy disk 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 floppy controller chips are not required for the machine to boot btw. So they would never be the cause of
			a core failure to boot.

			All the other various chips labelled as 47LSxxx are easily bought from eBay or RS, Farnell etc. Even the older ones.

			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 recouped back
			via eBay, should the board be duff.


			'''REMOVING CHIPS:'''

			A subject often treated with a fear that is unwarranted. Just observe the following:

			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. 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 highest point, closest to
			the chip itself. 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.

	~~For~~ the ~~floppy control circuitry~~, the ~~NEC 765 controller can still be acquired but the SEC9420C buffer is~~ a ~~hard~~ one ~~to track down~~.		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
	~~Luckily these are virtually never needed as you are likely~~ to ~~have replaced everything else before getting round~~ to ~~that anyway~~.		tweezers and your soldering iron to pluck out each pin in one piece. Hold the pin with the tweezers, melt the solder with the tip
			of the iron and pluck the pin out of its hole. Like plucking eyebrows, or so I am told. Then use your de-solder pump and soldering iron to
			suck out the solder from the holes where the pins were, ready for a chip DIP socket to be installed.

	~~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~~		This is a slow process but be calm and methodical and you wont go wrong.
	~~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~~.

Deriss at 16:00, 4 April 2017

2017-04-04T16:00:16Z

← Older revision		Revision as of 16:00, 4 April 2017
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	Now carefully remove the case.. Be '''VERY''' careful with any keyboard membranes. You '''CANNOT''' buy these anymore.		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.		eBay is The best source for spare chips and other replacement components that I have found, btw.
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	to buy online if you look long enough.		to buy online if you look long enough.

	6: Check for damage to the edges of the board. these can often be fixed with a few wires to re-route broken tracks.		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 tracks and back where it was supposed to go.


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	Capacitors and resistors are too cheap to mention. FYI: buying a bag of 5 is frequently little more expensive than buying just		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 excessive ~~and a waste of money~~.		1 or 2. Then you have spares as well. 85c rated parts are fine. 105c is also fine but excessive.

	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 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		The CRT controller UM6845R is about £4.50. They are all made by several different manufacturers, with very slightly
	that is over priced. ~~Look~~ at the chip model numbers on the cpc wiki mainboard images to check what will and wont work.		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. 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.		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,		It's a suppliers market for these unfortunately.. The two models NOT interchangeable as they have different
	even though some boards made potential allowance for either chip in their designs.		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.		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.		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.

Deriss at 15:32, 4 April 2017

2017-04-04T15:32:37Z

← Older revision		Revision as of 15:32, 4 April 2017
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	1: check the 5v power and 6pin display sockets for dry solder joints. A dab of fresh solder will fix this.		1: check the 5v power and 6pin display sockets for dry solder joints. A dab of fresh solder will fix this.

	2: check the rest of the board for dry joints too. This can be tedious but is worth it in the long run. Never touch the soldering iron tip to a joint for longer than 2 seconds to avoid damaging sensitive components.		2: check the rest of the board for dry joints too. This can be tedious but is worth it in the long run.
			Never touch the soldering iron tip to a joint for longer than 2 seconds to avoid damaging sensitive components.

	3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked and damaged one.		3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked
	Remember to replace any capacitor with a product of equal or higher voltage rating. ~~Equal~~ ones are ~~now~~ frequently physically smaller than the 1980's originals.		and damaged one. Remember to replace any capacitor with a product of equal or higher voltage rating.
			Equivalent ones are nowadays frequently physically much smaller than the 1980's originals. So don't be surprised.

	4: examine all resistors for signs or damage or discolouration. check resistance with ~~multimeter~~ and replace as needed.		4: examine all resistors for signs or damage or discolouration. check resistance with multi meter and replace as needed.

	5: Examine all the chips for any corrosion, damage or discolouration. ~~All~~ the components are still available to buy if you look ~~hard~~ enough.		5: Examine all the chips for any corrosion, damage or discolouration. Virtually all the components are still available
			to buy online if you look long enough.

			6: Check for damage to the edges of the board. these can often be fixed with a few wires to re-route broken tracks.


	'''REPLACEMENT PARTS :'''		'''REPLACEMENT PARTS :'''

			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 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 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 made by several different manufacturers, with very slightly differing model numbers for what is the same product. So shop around first before buying one that is over priced.		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 at the chip model numbers on the cpc wiki mainboard images to check what will and wont work.
	~~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~~.

	The ~~gate arrays~~, ~~usually~~ either Amstrad 40007 or 40010 are the only expensive parts at between £8 and £15.		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.. ~~They are~~ NOT interchangeable as they have different pinouts.		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.

	~~The last models of 464/6128 had an integrated SMD chip that removed~~ the ~~need for~~ a ~~gate array~~. these ~~cannot be swapped out and so would render any suck board~~ as ~~scrap. In~~ that ~~case cannibalise it and sell the parts~~.		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.

	~~One common fault is probably someone having plugged~~ a ~~12v PSU into~~ the ~~5v socket~~.		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.
	~~This usually fries some or all of the ram (memory)~~ and ~~may sometimes damage a few ceramic capacitors along~~ the ~~way too~~.

Deriss at 14:49, 4 April 2017

2017-04-04T14:49:25Z

← Older revision		Revision as of 14:49, 4 April 2017
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	Now carefully remove the case.. Be '''VERY''' careful with any keyboard membranes. You '''CANNOT''' buy these anymore.		Now carefully remove the case.. Be '''VERY''' careful with any keyboard membranes. You '''CANNOT''' buy these anymore.

	~~Btw:~~ eBay is The best source for spare chips and other replacement components that I have found		eBay is The best source for spare chips and other replacement components that I have found, btw.


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	2: check the rest of the board for dry joints too. This can be tedious but is worth it in the long run. Never touch the soldering iron tip to a joint for longer than 2 seconds to avoid damaging sensitive components.		2: check the rest of the board for dry joints too. This can be tedious but is worth it in the long run. Never touch the soldering iron tip to a joint for longer than 2 seconds to avoid damaging sensitive components.

	3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked one.		3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked and damaged one.
	Remember to replace any capacitor with a product of equal or higher voltage rating. Equal ones are now frequently physically smaller than the 1980's originals.		Remember to replace any capacitor with a product of equal or higher voltage rating. Equal ones are now frequently physically smaller than the 1980's originals.

	4: examine all resistors for signs or damage or discolouration. check resistance with multimeter and replace as needed.		4: examine all resistors for signs or damage or discolouration. check resistance with multimeter and replace as needed.

	5: Examine all the chips for any corrosion, damage or discolouration.		5: Examine all the chips for any corrosion, damage or discolouration. All the components are still available to buy if you look hard enough.


			'''REPLACEMENT PARTS :'''

	The ~~main~~ Z80 cpu can be replaced for £3 and is ~~always socketed~~. ~~The rest can be sourced for between £2 and £6 each from eBay, if you look around~~. ~~Capacitors and resistors~~ are ~~too cheap to be even worth mentioning. The gate array (40007~~, ~~40008 or 40010)~~ is the ~~only expensive part at between £9 and £15. (Suppliers market for those unfortunately~~..)		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 made by several different manufacturers, with very slightly differing model numbers for what is the same product. So shop around first before buying one that is over priced.

			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.

	The ~~most~~ common fault is probably someone having plugged a 12v PSU into the 5v socket. This usually fries some or all of the ram (memory) and may sometimes damage a few ceramic capacitors along the way too.		The gate arrays, usually either Amstrad 40007 or 40010 are the only expensive parts at between £8 and £15.
			It's a suppliers market for these unfortunately.. They are NOT interchangeable as they have different pinouts.

			The last models of 464/6128 had an integrated SMD chip that removed the need for a gate array. these cannot be swapped out and so would render any suck board as scrap. In that case cannibalise it and sell the parts.

			One common fault is probably someone having plugged a 12v PSU into the 5v socket.
			This usually fries some or all of the ram (memory) and may sometimes damage a few ceramic capacitors along the way too.

Deriss at 14:07, 4 April 2017

2017-04-04T14:07:48Z

← Older revision		Revision as of 14:07, 4 April 2017
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	'''<big>Bought a 464 or 6128 from eBay ? ~~Not~~ working ? ~~Then read~~ on..</big>'''		'''<big>Bought a 464 or 6128 from eBay ? Broken or not working right ? Read on..</big>'''


	Firstly, make sure ~~your~~ 5v '''~~REGULATED~~''' power supply and monitor / tv are working ok. (You'd be surprised...)		Firstly, make sure you have a 5v '''''regulated''''' power supply and that your monitor / tv are working ok. (You'd be surprised...)

	Make sure your power supply provides a '''minimum''' of 2A continuous current. Some PSUs can be very "optimistic".		Make sure your power supply provides a '''minimum''' of 2A continuous current. Some PSUs can be very "optimistic".
Line 11:		Line 11:


	Now carefully remove the case. Be ~~bl00dy~~ careful with any keyboard membranes. You '''CANNOT''' buy these anymore.		Now carefully remove the case.. Be '''VERY''' careful with any keyboard membranes. You '''CANNOT''' buy these anymore.

			Btw: eBay is The best source for spare chips and other replacement components that I have found
	Btw: eBay is ~~one of the~~ best ~~sources~~ for spare chips and replacement components.

Deriss at 14:01, 4 April 2017

2017-04-04T14:01:20Z

← Older revision		Revision as of 14:01, 4 April 2017
Line 2:		Line 2:


	Firstly, make sure your 5v power supply and monitor are working ok. (You'd be surprised...)		Firstly, make sure your 5v '''REGULATED''' power supply and monitor / tv are working ok. (You'd be surprised...)

	~~Check it with a multi meter and make~~ sure it provides a minimum of 2A continuous current.		Make sure your power supply provides a '''minimum''' of 2A continuous current. Some PSUs can be very "optimistic".

	~~Some modern switch mode PSUs are very optimistic in their "ratings~~".		On the 6128, you don't need a 12v feed for anything except the 3" disk drive. So it can be omitted for testing.

	~~You don~~'~~t need~~ a ~~12v feed for anything except the 3" disk drive~~. ~~So it can be omitted for testing~~.		Earth yourself to prevent static damage or better yet, get an anti-static strap. It's a 30 year old machine remember...

	~~Earth yourself to prevent static damage or better yet, get an anti-static strap. 30yr old machine remember...~~

			Now carefully remove the case. Be bl00dy careful with any keyboard membranes. You '''CANNOT''' buy these anymore.

	~~The obvious things to check first are:~~

	1: ~~check~~ the ~~5v power socket~~ and ~~DIN6 display socket for dry solder joints~~.		Btw: eBay is one of the best sources for spare chips and replacement components.

	~~2: check the rest of the board for dry joints too. Never touch the soldering iron tip onto a joint for longer than 2 seconds. This is to avoid damaging components.~~

	3: ~~Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked one.~~		The obvious things on the board to look for first are:

	4: ~~Examine all~~ the ~~chips~~ for ~~any corrosion, damage or discolouration~~.		1: check the 5v power and 6pin display sockets for dry solder joints. A dab of fresh solder will fix this.

	~~The most common fault~~ is ~~probably someone having plugged~~ a ~~12v PSU into the 5v socket and damaged~~		2: check the rest of the board for dry joints too. This can be tedious but is worth it in the long run. Never touch the soldering iron tip to a joint for longer than 2 seconds to avoid damaging sensitive components.

	This usually fries some or all of the ram (memory) and may sometimes damage a		3: Check for any damaged or leaking capacitors. Check the ceramic ones too, in case a previous owner has knocked one.
	few ceramic capacitors along the way.		Remember to replace any capacitor with a product of equal or higher voltage rating. Equal ones are now frequently physically smaller than the 1980's originals.

			4: examine all resistors for signs or damage or discolouration. check resistance with multimeter and replace as needed.

			5: Examine all the chips for any corrosion, damage or discolouration.



			The main Z80 cpu can be replaced for £3 and is always socketed. The rest can be sourced for between £2 and £6 each from eBay, if you look around. Capacitors and resistors are too cheap to be even worth mentioning. The gate array (40007, 40008 or 40010) is the only expensive part at between £9 and £15. (Suppliers market for those unfortunately..)


			The most common fault is probably someone having plugged a 12v PSU into the 5v socket. This usually fries some or all of the ram (memory) and may sometimes damage a few ceramic capacitors along the way too.

Deriss at 13:31, 4 April 2017

2017-04-04T13:31:20Z

@@ Line 1: / Line 1: @@
-'''Bought a 6128 from eBay and its not working ?  Then read on..'''
+'''<big>Bought a 464 or 6128 from eBay ? Not working ?  Then read on..</big>'''
-The most common fault is probably someone having plugged a 12v PSU into the 5v socket.
+Check it with a multi meter and make sure it provides a minimum of 2A continuous current.
 This usually fries some or all of the ram (memory) and may sometimes damage a
 few ceramic capacitors along the way.

Deriss at 13:19, 4 April 2017

2017-04-04T13:19:50Z

← Older revision		Revision as of 13:19, 4 April 2017
Line 1:		Line 1:
	~~<big>~~'''~~Common Faults on~~ a ~~CPC~~ 6128:'''~~</big>~~		'''Bought a 6128 from eBay and its not working ? Then read on..'''

	~~Bought a 6128 from eBay~~ and ~~not~~ working ~~? Read on~~..		Firstly, make sure your 5v power supply and monitor are working ok. (You'd be surprised...)

	~~Assuming the power supply and monitor are working, the~~ most common fault is
	probably someone having plugged a 12v PSU into the 5v socket.		The most common fault is probably someone having plugged a 12v PSU into the 5v socket.

	This usually fries some or all of the ram (memory) and may sometimes damage a		This usually fries some or all of the ram (memory) and may sometimes damage a
	few ceramic capacitors along the way.		few ceramic capacitors along the way.

Deriss at 13:16, 4 April 2017

2017-04-04T13:16:04Z

← Older revision		Revision as of 13:16, 4 April 2017
Line 1:		Line 1:
	'''Common Faults on a CPC 6128:'''~~<big>~~		<big>'''Common Faults on a CPC 6128:'''</big>
	</big>

	Bought a 6128 from eBay and not working ? Read on..		Bought a 6128 from eBay and not working ? Read on..

	Assuming the power supply and monitor are working, the most common fault is probably someone having plugged		Assuming the power supply and monitor are working, the most common fault is
	a 12v PSU into the 5v socket.		probably someone having plugged a 12v PSU into the 5v socket.

	This ~~is not~~ the ~~disaster it might seem though~~		This usually fries some or all of the ram (memory) and may sometimes damage a
			few ceramic capacitors along the way.

← Older revision		Revision as of 17:08, 4 April 2017
Line 1:		Line 1:
	'''<big>Bought a 464 or 6128 from eBay ? Broken or not working right ? Read on..</big>'''		'''<big>Bought a 464 or 6128 from eBay ? Broken or not working right ? Read on for repair tips and where to buy spares..</big>'''


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	The last versions of the 464/6128 (1989/90) had a more modern integrated SMD chip that removed the need for a gate array.		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		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 back		as scrap, if it turned out to be the SMD chip. Avoid any major expenditure on these boards that you could not recouped back
	via eBay, should the board be ~~duff~~.		via eBay, should the board be beyond repair.


Line 82:		Line 82:
	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,		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		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. Maplin sell all of		stand for it with a sponge for wiping off crud from the tip. A simple de-solder pump with plastic tip is also needed.
	these, as do eBay.		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~~ highest point, closest to		Now you are ready. Clean of any dust from the chip in question and carefully snip the legs off the chip at their highest point, closest to
	the chip itself. 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.		the chip itself as 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		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
Line 93:		Line 94:
	suck out the solder from the holes where the pins were, ready for a chip DIP socket to be installed.		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.		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 !