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Cite to Amstrad's own CPC464 service manual and CPCWiki's board catalogue; correct the display spec (no 640x400 mode - all three CPC modes are 200 lines), state that the monitor is the power supply and that there is no fan, add the real board-version table (Z70373 and 28032 do not exist), Gate Array is IC116 part 40007, and note that 12 of the 14 electrolytics are on the cassette sub-PCB
 
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{{Infobox computer
{{Infobox computer
| name        = CPC 464
| name        = Amstrad CPC 464
| logo        = [[File:Amstrad CPC logo.svg|150px]]
| logo        = [[File:Amstrad CPC logo.svg|150px]]
| image        = [[File:464.jpeg|260px|frameless]]
| image        = [[File:464.jpeg|260px|frameless]]
| caption      = 464 with the colour monitor
| caption      = CPC 464 with the colour monitor
| developer    = Amstrad
| developer    = Amstrad
| manufacturer = Amstrad
| manufacturer = Amstrad Consumer Electronics plc
| type        = Home Computer
| type        = Home computer
| release date = 21st of June 1984
| release date = 21 June 1984
| discontinued = 1990
| discontinued = 1990
| price        = £249 Monochrome / £359 Colour
| price        = £249 with green monitor / £359 with colour monitor
| cpu          = Zilog Z80 @ 4 MHz
| cpu          = Zilog Z80A @ 4 MHz
| memory      = 64 KB RAM (expandable to 4 MB)
| memory      = 64 KB RAM (over 42 KB available to the user)
| storage      = Integrated Cassette player @ 1000/2000 baud
| rom          = 32 KB — OS and Locomotive BASIC 1.0
| display      = RGB video @ 640*400
| storage      = Integrated cassette deck, 1000 or 2000 baud
| sound        = General Instrument AY-3-8912
| display      = 160×200×16, 320×200×4 or 640×200×2 from a 27-colour palette
| os          = CPC OS
| sound        = General Instrument AY-3-8912, three voices
| successor    = [[Amstrad 464 Plus]]
| power        = 5 V DC from the monitor. '''No mains connection and no internal power supply'''
| model        = 464
| os          = Amstrad firmware with Locomotive BASIC 1.0
}}The CPC 464 features 64 KB RAM and an internal cassette deck. It was introduced on the 21st of June 1984 in the UK. Initial retail prices for the CPC 464 were £249.00 with a green monochrome monitor and £359.00 with a colour monitor. Following the introduction of the [[Amstrad CPC 6128|CPC 6128]] in late 1985, retail prices for the CPC 464 were cut by £50.00
| successor    = Amstrad 464 Plus
| model        = CPC 464
}}
<templatestyles src="Template:StyledTable/styles.css" />


In 1990, the [[Amstrad 464 Plus|464 Plus]] replaced the CPC 464 in the model line-up, and production of the CPC 464 was discontinued, it sold over 2 million units during it's 6 year lifespan, making it one of the most successful computers in Europe.
The '''Amstrad CPC 464''' is a home computer introduced on 21 June 1984, with 64 KB of RAM and an integrated cassette deck in the keyboard unit. It was sold as a complete system with a monitor — £249 with the green GT64, £359 with the CTM640 colour monitor — and the monitor is not an accessory: '''it is where the machine's power comes from.'''
= Architecture =
 
*'''CPU''' Zilog Z80 clocked at 4MHZ
'''The part numbers and specification figures on this page are Amstrad's own''', from the ''CPC464 Micro Computer / CTM640 Colour Monitor / GT64 Green Monitor Service Manual'' hosted on this wiki.<ref name="sm464">Amstrad Consumer Electronics plc, ''CPC464 Micro Computer / CTM640 Colour Monitor / GT64 Green Monitor Service Manual''. Hosted at [[Amstrad CPC 464 Service Manual]]. Source for the technical specification, the CPC464 Cabinet Parts List, the Cassette Mechanism Parts List and alignment instructions, the Cassette PCB layout, the Basic Hardware Analysis flow chart and the CPC464 Electrical Parts List (page 17), which gives value, circuit reference and Amstrad part number for every component on the machine.</ref><ref name="cpcwikimb">[https://www.cpcwiki.eu/index.php/Mainboard_Versions "Mainboard Versions"], CPCWiki. Community catalogue of silkscreen markings, board dimensions, copyright dates and per-version changes for the CPC 464, 664 and 6128 main boards. Secondary source, compiled from observed boards.</ref>
*'''RAM''' 64KB of internal memory expandable up to 4MB
 
*'''ROM''' 32KB ROM chip that contains the OS and BASIC
== The monitor is the power supply ==
*'''SOUND''' The 464 uses a General Instrument AY-3-8912 sound chip that can provide 3 channels configurable to either a square wave or white noise.
 
'''The CPC 464 has no mains connection and no internal power supply.''' It takes 5 V DC through a socket on the back, and Amstrad's own specification says this is "supplied exclusively from screen system" — the CTM640 or the GT64.<ref name="sm464" /> Mains enters the '''monitor''', not the computer.
 
* '''The computer is safe to open.''' There is no mains voltage anywhere in the keyboard unit.
* '''The monitor is not.''' Both monitors contain a CRT with a lethal anode charge and mains-derived bulk capacitors that hold their charge after switch-off. See [[CRT Discharge Procedure]].
* '''A "dead CPC" is very often a dead monitor.''' Amstrad's own fault chart sends you to the monitor's 5 V output and the DC cord before anything on the computer board.<ref name="sm464" />
 
'''There is no cooling fan.''' No fan or fan motor appears anywhere in Amstrad's parts lists; the machine is passively cooled.<ref name="sm464" />
 
== Architecture ==
 
* '''CPU''' — Zilog Z80A at '''4 MHz'''. The Gate Array inserts wait states so that video and CPU accesses do not collide, which is why measured throughput is below what a clean 4 MHz Z80 would give.
* '''RAM''' — 64 KB, of which Amstrad's specification says '''over 42 KB is available to the user'''. The video memory is part of the same 64 KB.
* '''ROM''' — '''32 KB''', holding the operating system and Locomotive BASIC 1.0.
* '''Video''' — a 6845 CRT controller with the Gate Array generating the pixel pipeline.
* '''Sound''' — General Instrument '''AY-3-8912''', three voices, eight octaves in Amstrad's wording for the 664 and seven for the 464.
* '''I/O''' — an 8255 parallel interface for the keyboard, the AY control lines and the cassette motor.
 
'''The Gate Array on the original board is IC116, marked 20RA043, Amstrad part number 40007''', and it is the version with a cooling plate.<ref name="sm464" /> Later boards use different Gate Array parts, and the final cost-down board replaces it entirely.
 
== Display ==
 
Three modes, all 200 lines, from a 27-colour palette:
 
{| class="wikitable styled-table" style="width:70%; text-align:left;"
|+'''Video modes'''
! Mode !! Resolution !! Colours !! Text
|-
| 0 || 160 × 200 || 16 || 20 columns
|-
| 1 || 320 × 200 || 4 || 40 columns
|-
| 2 || 640 × 200 || 2 || 80 columns
|}
 
'''There is no 640 × 400 mode.''' The CPC's vertical resolution is 200 lines in every mode.
 
== Board versions ==
 
The main PCB went through four broad versions, identified by the silkscreened part number. The chip set, the board size and the keyboard connector all differ.<ref name="cpcwikimb" />
 
{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Amstrad CPC 464 main PCB versions'''
! Version !! Silkscreen !! Size !! Notes
|-
| '''v1''' (©1983) || Z70100 (no MC code), 270100 MC0001A, or Z70100 MC0001A || 405 × 155 mm || Gate Array with a cooling plate; VCC2 fed through R138/R139
|-
| '''v2''' (©1984) || Z70200 with MC0001A, MC0002A/B/C/D, MC0003A, MC0008B/C/D || 405 × 152 mm || Solder pads for both the old and the new Gate Array; 6128-style 2 × 10-pin dual-foil keyboard connector
|-
| '''v3''' || Z70374 MC0044A, Z70374 MC0044B, Z70375 MC0044D, Z70378 MC0046A || 240 × 150 / 238 × 145 mm || Same parts packed tighter; joystick and stereo sockets moved to the left
|-
| '''v4''' cost-down (©1988) || '''Z80329 MC0099A''' || 237 × 108 mm || 100-pin SMD ASIC (part 40226) combining the Gate Array, CRTC and some FDC, DRAM and reset logic
|}
 
'''Z70373 and "28032" are not CPC 464 board numbers.''' Neither appears in Amstrad's documentation or in CPCWiki's catalogue of observed boards; the real numbers are the ones above.<ref name="cpcwikimb" />
 
'''Z70200 is a CPC 464 board.''' If you are looking at a machine with a disc drive and a Z70200 silkscreen, something has been swapped — the [[Amstrad CPC 664]] board is Z70205.<ref name="cpcwikimb" />
 
== Storage ==
 
An integrated cassette deck running at 1000 or 2000 baud, selectable from software. The mechanism and its alignment instructions are in Amstrad's manual; the deck has its own sub-PCB.<ref name="sm464" />
 
'''Almost the whole capacitor problem on this machine is on the cassette board.''' Amstrad's parts list gives fourteen electrolytics across the machine, and '''only C101 and C102 are on the main PCB''' — the other twelve are 300-series parts on the cassette PCB.<ref name="sm464" /> Values are on [[Amstrad CPC 464 Capacitor Replacement Guide]].
 
== Servicing ==
 
* [[Amstrad CPC 464 Maintenance Guide]] — board identification, opening the unit, the cassette deck and its alignment, cleaning
* [[Amstrad CPC 464 Troubleshooting Guide]] — Amstrad's own hardware and software analysis charts
* [[Amstrad CPC 464 Capacitor Replacement Guide]] — Amstrad's complete electrical parts list
* [[Amstrad CPC 464 Service Manual]] — the document itself
 
== Related pages ==
* [[Amstrad CPC 664]]
* [[Amstrad CPC 464 Maintenance Guide]]
* [[Amstrad CPC 464 Troubleshooting Guide]]
* [[Amstrad CPC 464 Capacitor Replacement Guide]]
* [[CRT Discharge Procedure]]
 
== References ==
<references />
 
{{Navbox-Amstrad|state=collapsed}}
 
[[Category:Amstrad]]
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