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Link to Amstrad CPC 664 Service Manual on the wiki
Major corrections against Amstrad's own service manual: the board is Z70205 MC0005A/B, not Z70200 (a 464 board); the OS ROM is part 40022 at IC103, not 40012 (which is IC211, a 74LS27); the Gate Array is the 40010, not 40007/40226; the drive is a Matsushita EME-150A on PCB 30001, not a Hitachi HD3.5R-1; Amstrad's own disc capacities are SYSTEM 169 KB, DATA 178 KB, IBM 154 KB; the display is not interlaced and there is no 400-line mode; DC jack is J301 and the 5-pin DIN J302 is the cassette so...
 
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| logo        = [[File:Amstrad CPC logo.svg|150px]]
| logo        = [[File:Amstrad CPC logo.svg|150px]]
| image        = [[File:Amstrad CPC 664 with colour monitor.jpg|260px]]
| image        = [[File:Amstrad CPC 664 with colour monitor.jpg|260px]]
| caption      = Amstrad CPC 664 with the CTM-644 colour monitor
| caption      = Amstrad CPC 664 with the CTM644 colour monitor
| developer    = Amstrad
| developer    = Amstrad
| manufacturer = Amstrad
| manufacturer = Amstrad Consumer Electronics plc
| type        = Home computer
| type        = Home computer
| release date = April 1985
| release date = 1985
| discontinued = August 1985 (~6 months on the market)
| discontinued = August 1985
| price        = £339 monochrome (GT-64/65) / £449 colour (CTM-644)
| cpu          = Zilog Z80A @ 4 MHz
| cpu          = Zilog Z80A @ 4 MHz
| memory      = 64 KB RAM + 32 KB ROM (OS v2 + Locomotive BASIC 1.1) on the main board, 16 KB AMSDOS ROM on the disc-controller daughter
| memory      = 64 KB RAM (over 41 KB available to the user)
| storage      = One built-in Hitachi-mechanism 3-inch single-sided floppy drive, 178 KB per side
| rom          = 32 KB OS and Locomotive BASIC 1.1, plus a 16 KB AMSDOS ROM
| display      = RGB and luminance + sync video (6-pin DIN); 27-colour palette, three modes (160×200×16, 320×200×4, 640×200×2)
| storage      = Built-in 3-inch single-sided disc drive, Matsushita EME-150A
| sound        = General Instrument AY-3-8912 (3 channels + noise)
| display      = 160×200×16, 320×200×4 or 640×200×2 from a 27-colour palette
| os          = Amstrad Firmware v2 + Locomotive BASIC 1.1 + AMSDOS / CP/M 2.2
| sound        = General Instrument AY-3-8912, three voices
| power        = 5 V DC and a separate 12 V disc feed, both from the monitor
| os          = Amstrad firmware, Locomotive BASIC 1.1, AMSDOS, CP/M 2.2
| predecessor  = [[Amstrad CPC 464]]
| predecessor  = [[Amstrad CPC 464]]
| successor    = Amstrad CPC 6128
| model        = CPC 664
| model        = 664
}}
}}
<templatestyles src="Template:StyledTable/styles.css" />


The '''Amstrad CPC 664''' (also branded '''Schneider CPC 664''' in West Germany, Switzerland and Austria) is the second computer in the [[Amstrad CPC 464|CPC]] line. It was announced in April 1985 and replaced the [[Amstrad CPC 464]]'s integrated cassette deck with a '''built-in Hitachi-mechanism 3-inch single-sided floppy drive''', and upgraded the operating system to firmware v2 with Locomotive BASIC 1.1 and the AMSDOS disc operating system in a separate 16 KB ROM. The Z80A CPU, the 64 KB system RAM, the AY-3-8912 sound chip, the 6845 CRTC and the Gate Array are otherwise unchanged from the CPC 464.
The '''Amstrad CPC 664''' (sold as the '''Schneider CPC 664''' in West Germany, Austria and Switzerland) is the second machine in the CPC line. It replaced the [[Amstrad CPC 464|CPC 464]]'s cassette deck with a built-in 3-inch disc drive, moved the disc controller onto the main board instead of the external DDI-1, and shipped Locomotive BASIC 1.1 with AMSDOS in a separate 16 KB ROM.


The CPC 664 had an unusually short production life: it was replaced after only six months on the market by the Amstrad CPC 6128, which doubled the RAM to 128 KB and changed the case mouldings. Total production was small &mdash; survivors are scarcer than either the 464 or the 6128.
'''It was on sale from May to August 1985''' before the CPC 6128 replaced it, which is why it is scarcer than either the 464 or the 6128 and why the community knowledge base around it is thinner.<ref name="cpcwiki664">[https://www.cpcwiki.eu/index.php/CPC664 "CPC664"], CPCWiki, citing ''Amstrad Action'' issue 1 (October 1985) page 8 for the May–August 1985 production window. CPCWiki gives no production figure for the 664, and none was found elsewhere. Secondary source.</ref> '''No production figure has ever been published''', so none is given here.


== History ==
'''The part numbers, designators and specification figures on this page are Amstrad's own''', from the service manual hosted on this wiki.<ref name="sm664">Amstrad Consumer Electronics plc, ''CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual''. Hosted at [[Amstrad CPC 664 Service Manual]]. Source for the CPC664 Basic Hardware Analysis, the Diagnostic Flow Chart, the Alignment Checks including test points and the EME-CF2 test disk, the Electrical Parts List, the Mechanism drawing and Mechanical Replacements procedures, and the Technical Specification.</ref><ref name="cpcwikimb">[https://www.cpcwiki.eu/index.php/Mainboard_Versions "Mainboard Versions"], CPCWiki. Community catalogue of silkscreen markings, board dimensions and per-version differences across the CPC range. Gives the CPC664 board as Z70205 / MC0005A and MC0005B and notes the MC0005B's unlabelled patch resistor R160. Secondary source, compiled from observed boards.</ref>


By late 1984 the CPC 464 was selling strongly in the UK, France, West Germany and Spain, but the integrated cassette deck was a serious limitation for business and education uses where the AMSOFT / Locomotive Software business titles (e.g. Tasword 464, AMSCALC, AMSWORD) needed floppy storage to be practical. The external Amstrad DDI-1 disc interface had been offered since November 1984, but it added a separate box, a 22-pin floppy ribbon, and a second power adapter.
== The monitor is the power supply ==


The CPC 664 was Amstrad's response: a single all-in-one case with the cassette deck physically replaced by a Hitachi 3-inch drive mechanism, the disc interface electronics moved onto the main PCB (instead of being on a separate DDI-1 unit), and the OS extended with built-in AMSDOS support. The original list price (April 1985) was '''£339''' with a GT-64 / GT-65 green monochrome monitor and '''£449''' with the CTM-644 colour monitor &mdash; a £90 premium over the equivalent CPC 464.
Like the 464, '''the CPC 664 has no mains connection and no internal power supply''' — but it needs '''two''' DC feeds, not one. Amstrad's specification lists a socket for the 5 V supply from the monitor, and a plug and lead that goes '''out''' to the 12 V disc power socket on the monitor.<ref name="sm664" /> The CTM644 colour monitor and the GT65 green monitor provide both.


In August 1985 Amstrad announced the CPC 6128, which doubled the RAM to 128 KB and used a more compact case in the European style. The CPC 6128 was sold concurrently with the CPC 664 for a short period before the 664 was discontinued. As a result the CPC 664 was only on the market for approximately six months and remains the rarest of the original three CPC machines.
In the parts list these are '''J301''' (DC jack, Amstrad part 170024 — the same part as the 464's J104) and '''CD301''' (DC cord, part 170822).<ref name="sm664" />


== Architecture ==
'''There is no five-pin DIN power connector on this machine.''' The 5-pin DIN on the back is '''J302''' (part 170819), the '''external cassette recorder''' socket; the 3.5 mm socket is '''J103''', stereo audio out.<ref name="sm664" />


The CPC 664 shares its core architecture with the [[Amstrad CPC 464]]. The differences are concentrated around the floppy disc subsystem and the ROM map.
'''A drive that will not spin is very often a 12 V problem, not a drive problem.''' That rail comes down a separate lead from the monitor and that lead is a single point of failure. Check it before opening the drive.


* '''CPU''': Zilog '''Z80A''' at 4 MHz. The main system clock is generated by the Gate Array from a 16 MHz crystal (X101). Same chip as in the CPC 464.
== Board ==
* '''RAM''': '''64 KB''' organised as eight 64K&times;1 dynamic RAM chips (4164 / HM4864P-2 family) at the IC117&ndash;IC124 positions on the main PCB. Same as CPC 464. The upper 16 KB is also used as video RAM; the Gate Array multiplexes Z80 and video access. No bank-switching hardware &mdash; the 64 KB is the full main-RAM ceiling.
* '''ROM''': '''32 KB''' on the main PCB at IC103, holding Amstrad Firmware v2 (16 KB OS) and Locomotive BASIC 1.1 (16 KB) in a single mask ROM (Amstrad part number 40012). The CPC 664 BASIC 1.1 is forwards-compatible with the CPC 464 BASIC 1.0 but adds the disc commands (LOAD"!", SAVE"!", CAT, ERA, REN, |DIR, |ERA, |REN, |USER and so on).
* '''Disc ROM''': An additional '''16 KB AMSDOS ROM''' (Amstrad part number 40015) is fitted at a separate socket on the disc-controller area of the main PCB. AMSDOS is the Amstrad implementation of disc I/O, providing the firmware that handles file system, directory, sector read/write and disc command operations through the |&nbsp;(bar) command extensions. Same AMSDOS ROM is used in the CPC 664 and the CPC 6128.
* '''Sound''': General Instrument '''AY-3-8912''' at IC102, clocked at 1 MHz from the Gate Array. 3 channels of square-wave + 1 channel of noise, programmable envelope. Same chip as in the CPC 464.
* '''CRT controller''': '''6845-family CRTC''' at IC108, clocked at 1 MHz. Most CPC 664s ship with the '''Type 0''' HD6845SP CRTC, although some later units ship with Type 1 (UM6845R). See the CRTC type table on CPCWiki for the rare programming differences between types.
* '''PIO''': '''Intel 8255A-5''' (or M5L8255AP-5) at IC107 for keyboard input, AY-3-8912 control, cassette motor + printer strobe (the cassette interface is still wired through to the expansion port even though the deck itself is removed), and DIP switch reading.
* '''Gate Array''': '''40010''' or '''40007''' (occasionally '''40226''' on later units). The Gate Array generates all system clocks, the video pixel pipeline, and the 8 KB Mode Lookup Table for the three video modes.
* '''Floppy disc controller''': '''NEC uPD765A''' (or compatible NEC D765AC-2). Provides FM/MFM, single and double-density read/write, single-track support. The CPC 664 firmware uses MFM single-sided at 250 kbit/s, giving 178 KB per side on a 3-inch 40-track diskette.
* '''Floppy disc drive''': Built-in '''Hitachi HD3''' family 3-inch drive (typically HD3.5R-1 or compatible). 40 tracks, 9 sectors of 512 bytes per track, single-sided. The disc is the same Maxell / Amsoft / Panasonic 3-inch hard-shell media that became identified with Amstrad and was the only commercially successful application of the format.


The 664 main PCB silkscreen is part-number '''Z70200''' / '''MC0030''' (or similar by region). The PCB layout is electrically identical to the CPC 6128 main PCB except for the smaller RAM bank (8 chips instead of 16) and the absence of the RAM bank-switching logic at IC131.
The CPC 664 main board is '''Z70205''', 475 × 155 mm, in two variants:<ref name="cpcwikimb" />


== Storage ==
{| class="wikitable styled-table" style="width:95%; text-align:left;"
|+'''CPC 664 main PCB variants'''
! Silkscreen !! Notes
|-
| '''Z70205 MC0005A''' || 8-pin FDC data separator
|-
| '''Z70205 MC0005B''' || German Schneider boards. Usually carries a patch resistor '''R160''' between pin 9 (A0) and pin 14 (/CASADDR) of IC105, which is '''not labelled on the PCB''' — do not mistake it for a previous owner's bodge
|}


The integrated 3-inch single-sided drive:
'''Z70200 is a CPC 464 board, not a 664 board.'''<ref name="cpcwikimb" /> If your board is marked Z70200, you are looking at a 464.


* '''Mechanism''': Hitachi HD3.5R-1 or equivalent. Single-motor design with a rubber drive belt between the motor pulley and the drive spindle.
== Devices ==
* '''Capacity''': '''178 KB per disc side''', 40 tracks &times; 9 sectors &times; 512 bytes. Each diskette is flipped manually to access the second side ("flip side").
* '''Interface''': Single-cable connection from the drive to the main PCB at the rear of the disc bay.
* '''Speed''': 300 rpm.
* '''Data rate''': 250 kbit/s MFM.
* '''Disc formats supported by AMSDOS''': System format (178 KB, with reserved boot sector and CP/M 2.2 file system), Data format (178 KB, no boot sector), IBM format (160 KB, MS-DOS-style).
* '''Disc cost''': Maxell, Amsoft and Panasonic were the principal manufacturers; new old-stock blank 3-inch discs remain available in 2025 from dedicated Amstrad / Spectrum +3 retailers, but at premium prices.


A second external 3-inch (or 3.5-inch) drive can be added through the expansion port using the standard CPC FDC chain &mdash; the Amstrad DDI-3 add-on or a third-party Dragonfly / Hxc / GoTek emulator.
Amstrad's own parts list:<ref name="sm664" />


== Display ==
{| class="wikitable styled-table" style="width:95%; text-align:left;"
|+'''CPC 664 — principal devices'''
! Ref !! Device !! Amstrad part no. !! Role
|-
| '''IC103''' || TMM-23256P-1952 || '''40022''' || 32 KB OS + Locomotive BASIC 1.1 ROM
|-
| IC204 || TMM-23128P-1951 || 40015 || 16 KB AMSDOS ROM
|-
| IC111 || Z8400APS || 40080 || Z80A CPU
|-
| '''IC116''' || HSG3130 / HSG3170 || '''40010''' || Gate Array
|-
| IC108 || HD6845SP || 170106 || CRTC
|-
| IC107 || M5L8255AP-5 || 170105 || Parallel I/O
|-
| IC102 || AY-3-8912 || 40001 || Sound generator
|-
| IC117–IC124 || HM4864U-2 || 170110 || 64 KB DRAM, eight 64K × 1 devices
|-
| IC201 || µPD765AC || 40018 || Floppy disc controller
|-
| IC202 || FDC9216BT || 40020 || Data separator
|-
| IC301 || LA4140 || 170111 || Audio power amplifier
|-
| IC302 || LA63585 || 170814 || Cassette read chain
|}


The CPC 664 uses the same video subsystem as the CPC 464. Output is on a 6-pin DIN connector at J101 with:
Two corrections worth stating plainly, because both have circulated widely:
* Pin 1: Red
* Pin 2: Green
* Pin 3: Blue
* Pin 4: Sync (composite)
* Pin 5: GND
* Pin 6: Luminance (for the green GT-64 / GT-65 monitor)


Video modes:
* '''The OS ROM is part 40022 at IC103.''' '''40012 is IC211, a 74LS27''' — a different device entirely.<ref name="sm664" />
* '''Mode 0''': 160 &times; 200, 16 colours from the 27-colour palette. 20 columns of 8&times;8 text.
* '''The Gate Array is the 40010 at IC116.''' The heatsinked '''40007''' is the [[Amstrad CPC 464|CPC 464]]'s part, and the 40226 is the ASIC on the 464's late cost-down board. Neither belongs in a 664.<ref name="sm664" /><ref name="cpcwikimb" />
* '''Mode 1''': 320 &times; 200, 4 colours. 40 columns of 8&times;8 text.
* '''Mode 2''': 640 &times; 200, 2 colours. 80 columns of 8&times;8 text.


Refresh is 50 Hz interlaced (UK/EU PAL units) or 60 Hz (US/Japan NTSC units &mdash; rare). Vertical resolution is 200 lines doubled to 400 lines on the monitor for non-flickering display.
'''The 664 keeps the whole cassette interface even though it has no cassette deck.''' IC301, IC302, the tape motor relay RY301, the speaker, the volume control and the entire 300-series population are present, feeding J302 for an external recorder.<ref name="sm664" />


The CPC 664 supports light-pen input via the LPEN line on the expansion port (pin 47), but no light-pen was officially sold for the 664.
== The disc drive ==


== Keyboard ==
Amstrad's specification describes it as "a 3" system, conforming to the Hitachi/Panasonic standard", configured in software for a '''12 ms step rate and 30 ms settling time'''.<ref name="sm664" /> '''The mechanism actually fitted is the Matsushita EME-150A on PCB 30001''' — the PCB number Amstrad's own manual refers to throughout.<ref name="sm664" /><ref name="cpcfdd">[https://www.cpcwiki.eu/index.php/Amstrad_FDD_part "Amstrad FDD part"], CPCWiki — catalogue of the Matsushita EME-series 3-inch mechanisms Amstrad fitted: EME-150A (PCB 30001, CPC664, early DDI-1 and early 6128), EME-155 (PCB 30002), EME-156 (PCB Z70312), EME-156V (PCB Z80264) and the 5 V-only EME-157 (PCB Z80425). All single-sided, 40 track, 180 KB per side, 300 rpm. Secondary source.</ref> Later machines in the family used the EME-155, EME-156 and EME-156V.


74 keys in QWERTY layout. Same key matrix as the CPC 464 with a slight cosmetic difference: the function keys on the right-hand side keypad are blue plastic on the 664 (vs grey on the 464). The "JOY 0" and "JOY 1" labels on the cursor cluster are also blue.
A 3-inch disc is physically double-sided, with a write-protect clip on each side, but the drive reads only the side facing it — you flip the disc by hand.<ref name="sm664" />


National variants: QWERTY (English), QWERTY (Spanish), QWERTY (Danish), AZERTY (French). Each is paired with a different firmware ROM (40012 English, 40037 Spanish, 40050 French) and a different keyboard membrane.
=== Disc formats ===


== Audio ==
Amstrad's own figures. All are single-sided, double density, 512-byte sectors, 40 tracks, 2:1 interleave:<ref name="sm664" />


Same audio chain as the CPC 464:
{| class="wikitable styled-table" style="width:85%; text-align:left;"
* '''AY-3-8912''' at IC102 generates three independent square-wave channels plus a noise generator.
|+'''AMSDOS disc formats'''
* '''Mono internal speaker''' through IC301 (LA4140) with volume control VR301 (20 kΩ).
! Format !! Sectors per track !! Reserved tracks !! Capacity
* '''Stereo line output''' on 3.5 mm jack J103, mixed from the three AY channels (left = A, centre = B, right = C is the most common wiring).
|-
| '''SYSTEM''' || 9 || 2 || '''169 KB'''
|-
| '''DATA''' || 9 || none || '''178 KB'''
|-
| '''IBM''' || 8 || 1 || '''154 KB'''
|}


== Connectors ==
=== The drive belt ===


* '''J101''' (6-pin DIN female): RGB + sync + luminance. Power-supply output also routed through this DIN to the matching monitor on later units.
'''The perished belt is the characteristic 664 fault.''' The motor runs, the disc does not, and the machine reports a read failure on a known-good disc.
* '''J102''' (DB-9 male): joystick. Compatible with Atari 9-pin joysticks. Includes Fire 3 on pin 5 (undocumented) and Joystick 2 ground on pin 9.
* '''J103''' (3.5 mm stereo jack): line-level audio output.
* '''J104''' (2.1 mm DC socket, centre positive): '''5 V DC, 2 A''' system supply. On the 664 this also supplies the floppy drive logic. The drive's motor is separately powered through the same DC input.
* '''Printer port''' (34-pin PCB edge connector): Centronics parallel printer port, 7-bit data (D7 grounded), same as CPC 464.
* '''Expansion port''' (50-pin PCB edge connector): general-purpose system bus. The floppy drive is now '''internal''' so the expansion port no longer routes /EXP-FDC, but a second drive can be added through the expansion bus.


== Power Supply ==
Amstrad publishes no belt dimensions. The community specification for the CPC 664 / 6128 / FD-1 3-inch drive belt is '''3 mm wide, 0.6 mm thick, 230 mm outer circumference''' — often advertised as "115 mm", which is the flat length.<ref name="cpcbelt">[https://www.cpcwiki.eu/index.php/Changing_the_drive_belt "Changing the drive belt"], CPCWiki — gives the replacement belt as 3 mm wide, 0.6 mm thick and 230 mm outer circumference (commonly advertised as 115 mm), with the removal procedure. Secondary source; Amstrad published no belt dimensions.</ref> Measure your own pulleys before ordering.


The CPC 664 system unit takes '''5 V DC, 2 A''' on a 2.1 mm centre-positive jack at J104. This is supplied by the matching monitor:
'''The spindle speed is adjustable at VR201''' on the drive's own control PCB, to an index period of 200 ms — one revolution at 300 rpm.<ref name="sm664" /> Full procedure on [[Amstrad CPC 664 Maintenance Guide]].
* '''GT-64 / GT-65 green monitor''': supplies 5 V/2 A and the +12 V driver for the cathode.
* '''CTM-644 colour monitor''': supplies 5 V/2 A and additional rails for the colour CRT.


Unlike the CPC 464, the CPC 664 also needs '''+12 V at &asymp;0.6 A''' for the floppy drive motor and stepper. This is supplied through a separate pin on the modified DC cord, on units with a CTM-644; on GT-64/GT-65-only configurations, a dedicated 12 V supply was bundled. The exact pin assignment depends on the regional variant.
=== Amstrad's position on the mechanism ===


If using a third-party display, a stand-alone '''5 V / 2 A + 12 V / 1 A''' dual-output PSU is required.
Printed twice in the manual, in a box: '''"Service Agents must not carry out any repair or adjustment to the Drive mechanism and its associated PCB 30001 during warranty. Faulty mechanism must be returned to AMSTRAD for exchange."'''<ref name="sm664" /> That was a 1985 warranty policy, not a statement that the drive is unserviceable — but it does mean '''the manual gives no component values for the drive PCB''', and the parts list carries a matching note to that effect. The mechanical breakdown, the alignment checks and the replacement procedures are all there and all still usable.


== Submodels and Regional Variants ==
== Display ==


* '''Amstrad CPC 664''' (UK) &mdash; QWERTY keyboard, English firmware (40012).
The same video subsystem as the 464: three modes, all 200 lines, from a 27-colour palette.
* '''Schneider CPC 664''' (West Germany, Austria, Switzerland) &mdash; QWERTZ keyboard, German firmware. The Schneider brand was applied to all CPCs sold by Schneider Computer Division in the DACH region under a licensing agreement until 1988.
* '''Amstrad CPC 664''' (Spain) &mdash; QWERTY keyboard, Spanish firmware (40037), Spanish manuals.
* '''Amstrad CPC 664''' (France) &mdash; AZERTY keyboard, French firmware (40050), French manuals.


The 664 was not sold in the US.
{| 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
|}


== General Maintenance ==
'''The CPC display is not interlaced and there is no 400-line mode.''' Both claims appeared on earlier versions of this page and neither is correct.


Floppy drive belt replacement, head cleaning, keyboard and PCB cleaning, contact maintenance, and the floppy mechanism stepper lubrication are documented in [[Amstrad CPC 664 Maintenance Guide]].
== Amstrad's published specification ==


== Troubleshooting ==
{| class="wikitable styled-table" style="width:90%; text-align:left;"
|+'''CPC 664 — from Amstrad's specification page'''<ref name="sm664" />
! Item !! Figure
|-
| Processor || Z80A at 4 MHz
|-
| RAM / ROM || 64 KB RAM (over 41 KB available to the user) / 32 KB ROM for BASIC and OS
|-
| Video / sound / I/O || 6845 CRT controller · AY-3-8912, 3 voice, 8 octave · 8255 parallel I/O
|-
| Keyboard || 74 keys
|-
| Disc drive || 3 inch, 12 ms step rate, 30 ms settling time, maximum 2 drives
|-
| Expansion || Up to 252 additional 16 KB ROMs
|-
| Keyboard unit || 580 × 70 × 170 mm, 2.4 kg
|-
| CTM644 monitor || 375 × 340 × 365 mm, 10.6 kg
|-
| GT65 monitor || 305 × 315 × 335 mm, 6.3 kg
|-
| Mains || 240 V AC 50 Hz — '''at the monitor'''. Both the keyboard unit and the disc drive are powered from the screen system
|}


Symptom-based diagnostic, FDC failure analysis, drive belt symptoms, common AMSDOS errors and the Gate Array / RAM / CRTC failure analysis are documented in [[Amstrad CPC 664 Troubleshooting Guide]].
== Servicing ==


== Capacitor Replacement ==
* [[Amstrad CPC 664 Maintenance Guide]] — the drive, the belt, the VR201 spindle adjustment, cleaning
* [[Amstrad CPC 664 Troubleshooting Guide]] — Amstrad's diagnostic flow chart and alignment checks
* [[Amstrad CPC 664 Capacitor Replacement Guide]] — Amstrad's electrical parts list
* [[Amstrad CPC 664 Service Manual]] — the document itself


The CPC 664 main PCB inherits most of the [[Amstrad CPC 464]] capacitor positions and adds a small number of new capacitors on the disc-controller area. Full list with values, designators and the AMSDOS-area additions is in [[Amstrad CPC 664 Capacitor Replacement Guide]].
The keyboard, the audio chain and most of the main board are shared with the 464, so the [[Amstrad CPC 464 Maintenance Guide]] procedures apply to everything outside the disc subsystem.


== Gallery ==
== Gallery ==
<gallery mode="packed" heights="200">
<gallery mode="packed" heights="200">
File:Amstrad CPC 664 with colour monitor.jpg|Amstrad CPC 664 with CTM-644 colour monitor
File:Amstrad CPC 664 with colour monitor.jpg|CPC 664 with the CTM644 colour monitor
File:Amstrad CPC 664 ordinateur.jpg|CPC 664 system unit (close view of the floppy drive bay)
File:Amstrad CPC 664 ordinateur.jpg|The disc drive bay
File:Amstrad CPC 664 product photo.jpg|CPC 664 1985 catalogue product photo
File:Amstrad CPC 664 product photo.jpg|1985 catalogue photograph
</gallery>
</gallery>


== Related Pages ==
== Related pages ==
 
* [[Amstrad CPC 464]]
* [[Amstrad CPC 664 Maintenance Guide]]
* [[Amstrad CPC 664 Maintenance Guide]]
* [[Amstrad CPC 664 Troubleshooting Guide]]
* [[Amstrad CPC 664 Troubleshooting Guide]]
* [[Amstrad CPC 664 Capacitor Replacement Guide]]
* [[Amstrad CPC 664 Capacitor Replacement Guide]]
* [[Amstrad CPC 464]] &mdash; predecessor
* [[CRT Discharge Procedure]]
* Amstrad CPC 6128 &mdash; successor
* Amstrad CTM-644 colour monitor
 
 
== Service Manual ==
 
The official Amstrad Service Manual for this machine is available on the wiki: [[Amstrad CPC 664 Service Manual]].


== References ==
== References ==
<references />


* [https://en.wikipedia.org/wiki/Amstrad_CPC Amstrad CPC &mdash; Wikipedia]. Reference for the CPC line chronology, the 6-month production lifetime of the 664, and the relationship between the 464, 664 and 6128.
{{Navbox-Amstrad|state=collapsed}}
* [https://www.cpcwiki.eu/index.php/CPC_old_generation CPC old generation], CPCWiki. Source for the 664 release date (April 1985), the 6-month production window, the hardware differences from the 464 (built-in 3-inch floppy + 16 KB AMSDOS ROM), and the integration of AMSDOS into firmware v2.
* [https://www.grimware.org/doku.php/documentations/hardware/amstrad.cpc464 Amstrad CPC hardware documentation], Grimware. Source for the connector pinouts and the schematic-level architecture shared with the 464.
* [https://cpctech.cpcwiki.de/docs/cpcrev.html CPC hardware revisions], CPCWiki / cpctech.org.uk. Reference for the Gate Array variants (40007 / 40010 / 40226) and the per-revision IC list.
* [https://archive.org/details/Amstrad_CPC664_Service_Manual_1985_Amstrad_Consumer_Electronics Amstrad CPC664 Service Manual] (1985, Amstrad Consumer Electronics). Authoritative source for the disc controller area schematic, the disc drive parts list, drive alignment instructions and the electrical parts list (matches the CPC 464 main PCB for the non-disc areas).
* [https://www.amstrad-noob.com/category/cpc-664/ Amstrad noob &mdash; CPC 664 category]. Field-experience source for the most-common drive belt and CRTC failure modes on the CPC 664.
 
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[[Category:Amstrad]]
[[Category:Amstrad]]

Latest revision as of 20:20, 23 September 2026

Amstrad CPC 664
Amstrad CPC 664 with the CTM644 colour monitor
Specifications
DeveloperAmstrad
ManufacturerAmstrad Consumer Electronics plc
TypeHome computer
Released1985
DiscontinuedAugust 1985
CPUZilog Z80A @ 4 MHz
Memory64 KB RAM (over 41 KB available to the user)
StorageBuilt-in 3-inch single-sided disc drive, Matsushita EME-150A
Display160×200×16, 320×200×4 or 640×200×2 from a 27-colour palette
SoundGeneral Instrument AY-3-8912, three voices
ROM32 KB OS and Locomotive BASIC 1.1, plus a 16 KB AMSDOS ROM
Power5 V DC and a separate 12 V disc feed, both from the monitor
OS / FirmwareAmstrad firmware, Locomotive BASIC 1.1, AMSDOS, CP/M 2.2
PredecessorAmstrad CPC 464
Model no.CPC 664

The Amstrad CPC 664 (sold as the Schneider CPC 664 in West Germany, Austria and Switzerland) is the second machine in the CPC line. It replaced the CPC 464's cassette deck with a built-in 3-inch disc drive, moved the disc controller onto the main board instead of the external DDI-1, and shipped Locomotive BASIC 1.1 with AMSDOS in a separate 16 KB ROM.

It was on sale from May to August 1985 before the CPC 6128 replaced it, which is why it is scarcer than either the 464 or the 6128 and why the community knowledge base around it is thinner.[1] No production figure has ever been published, so none is given here.

The part numbers, designators and specification figures on this page are Amstrad's own, from the service manual hosted on this wiki.[2][3]

The monitor is the power supply

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Like the 464, the CPC 664 has no mains connection and no internal power supply — but it needs two DC feeds, not one. Amstrad's specification lists a socket for the 5 V supply from the monitor, and a plug and lead that goes out to the 12 V disc power socket on the monitor.[2] The CTM644 colour monitor and the GT65 green monitor provide both.

In the parts list these are J301 (DC jack, Amstrad part 170024 — the same part as the 464's J104) and CD301 (DC cord, part 170822).[2]

There is no five-pin DIN power connector on this machine. The 5-pin DIN on the back is J302 (part 170819), the external cassette recorder socket; the 3.5 mm socket is J103, stereo audio out.[2]

A drive that will not spin is very often a 12 V problem, not a drive problem. That rail comes down a separate lead from the monitor and that lead is a single point of failure. Check it before opening the drive.

Board

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The CPC 664 main board is Z70205, 475 × 155 mm, in two variants:[3]

CPC 664 main PCB variants
Silkscreen Notes
Z70205 MC0005A 8-pin FDC data separator
Z70205 MC0005B German Schneider boards. Usually carries a patch resistor R160 between pin 9 (A0) and pin 14 (/CASADDR) of IC105, which is not labelled on the PCB — do not mistake it for a previous owner's bodge

Z70200 is a CPC 464 board, not a 664 board.[3] If your board is marked Z70200, you are looking at a 464.

Devices

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Amstrad's own parts list:[2]

CPC 664 — principal devices
Ref Device Amstrad part no. Role
IC103 TMM-23256P-1952 40022 32 KB OS + Locomotive BASIC 1.1 ROM
IC204 TMM-23128P-1951 40015 16 KB AMSDOS ROM
IC111 Z8400APS 40080 Z80A CPU
IC116 HSG3130 / HSG3170 40010 Gate Array
IC108 HD6845SP 170106 CRTC
IC107 M5L8255AP-5 170105 Parallel I/O
IC102 AY-3-8912 40001 Sound generator
IC117–IC124 HM4864U-2 170110 64 KB DRAM, eight 64K × 1 devices
IC201 µPD765AC 40018 Floppy disc controller
IC202 FDC9216BT 40020 Data separator
IC301 LA4140 170111 Audio power amplifier
IC302 LA63585 170814 Cassette read chain

Two corrections worth stating plainly, because both have circulated widely:

  • The OS ROM is part 40022 at IC103. 40012 is IC211, a 74LS27 — a different device entirely.[2]
  • The Gate Array is the 40010 at IC116. The heatsinked 40007 is the CPC 464's part, and the 40226 is the ASIC on the 464's late cost-down board. Neither belongs in a 664.[2][3]

The 664 keeps the whole cassette interface even though it has no cassette deck. IC301, IC302, the tape motor relay RY301, the speaker, the volume control and the entire 300-series population are present, feeding J302 for an external recorder.[2]

The disc drive

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Amstrad's specification describes it as "a 3" system, conforming to the Hitachi/Panasonic standard", configured in software for a 12 ms step rate and 30 ms settling time.[2] The mechanism actually fitted is the Matsushita EME-150A on PCB 30001 — the PCB number Amstrad's own manual refers to throughout.[2][4] Later machines in the family used the EME-155, EME-156 and EME-156V.

A 3-inch disc is physically double-sided, with a write-protect clip on each side, but the drive reads only the side facing it — you flip the disc by hand.[2]

Disc formats

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Amstrad's own figures. All are single-sided, double density, 512-byte sectors, 40 tracks, 2:1 interleave:[2]

AMSDOS disc formats
Format Sectors per track Reserved tracks Capacity
SYSTEM 9 2 169 KB
DATA 9 none 178 KB
IBM 8 1 154 KB

The drive belt

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The perished belt is the characteristic 664 fault. The motor runs, the disc does not, and the machine reports a read failure on a known-good disc.

Amstrad publishes no belt dimensions. The community specification for the CPC 664 / 6128 / FD-1 3-inch drive belt is 3 mm wide, 0.6 mm thick, 230 mm outer circumference — often advertised as "115 mm", which is the flat length.[5] Measure your own pulleys before ordering.

The spindle speed is adjustable at VR201 on the drive's own control PCB, to an index period of 200 ms — one revolution at 300 rpm.[2] Full procedure on Amstrad CPC 664 Maintenance Guide.

Amstrad's position on the mechanism

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Printed twice in the manual, in a box: "Service Agents must not carry out any repair or adjustment to the Drive mechanism and its associated PCB 30001 during warranty. Faulty mechanism must be returned to AMSTRAD for exchange."[2] That was a 1985 warranty policy, not a statement that the drive is unserviceable — but it does mean the manual gives no component values for the drive PCB, and the parts list carries a matching note to that effect. The mechanical breakdown, the alignment checks and the replacement procedures are all there and all still usable.

Display

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The same video subsystem as the 464: three modes, all 200 lines, from a 27-colour palette.

Video modes
Mode Resolution Colours Text
0 160 × 200 16 20 columns
1 320 × 200 4 40 columns
2 640 × 200 2 80 columns

The CPC display is not interlaced and there is no 400-line mode. Both claims appeared on earlier versions of this page and neither is correct.

Amstrad's published specification

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CPC 664 — from Amstrad's specification page[2]
Item Figure
Processor Z80A at 4 MHz
RAM / ROM 64 KB RAM (over 41 KB available to the user) / 32 KB ROM for BASIC and OS
Video / sound / I/O 6845 CRT controller · AY-3-8912, 3 voice, 8 octave · 8255 parallel I/O
Keyboard 74 keys
Disc drive 3 inch, 12 ms step rate, 30 ms settling time, maximum 2 drives
Expansion Up to 252 additional 16 KB ROMs
Keyboard unit 580 × 70 × 170 mm, 2.4 kg
CTM644 monitor 375 × 340 × 365 mm, 10.6 kg
GT65 monitor 305 × 315 × 335 mm, 6.3 kg
Mains 240 V AC 50 Hz — at the monitor. Both the keyboard unit and the disc drive are powered from the screen system

Servicing

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The keyboard, the audio chain and most of the main board are shared with the 464, so the Amstrad CPC 464 Maintenance Guide procedures apply to everything outside the disc subsystem.

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  • CPC 664 with the CTM644 colour monitor
    CPC 664 with the CTM644 colour monitor
  • The disc drive bay
    The disc drive bay
  • 1985 catalogue photograph
    1985 catalogue photograph
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References

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  1. ↑ "CPC664", CPCWiki, citing Amstrad Action issue 1 (October 1985) page 8 for the May–August 1985 production window. CPCWiki gives no production figure for the 664, and none was found elsewhere. Secondary source.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 Amstrad Consumer Electronics plc, CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual. Hosted at Amstrad CPC 664 Service Manual. Source for the CPC664 Basic Hardware Analysis, the Diagnostic Flow Chart, the Alignment Checks including test points and the EME-CF2 test disk, the Electrical Parts List, the Mechanism drawing and Mechanical Replacements procedures, and the Technical Specification.
  3. ↑ 3.0 3.1 3.2 3.3 "Mainboard Versions", CPCWiki. Community catalogue of silkscreen markings, board dimensions and per-version differences across the CPC range. Gives the CPC664 board as Z70205 / MC0005A and MC0005B and notes the MC0005B's unlabelled patch resistor R160. Secondary source, compiled from observed boards.
  4. ↑ "Amstrad FDD part", CPCWiki — catalogue of the Matsushita EME-series 3-inch mechanisms Amstrad fitted: EME-150A (PCB 30001, CPC664, early DDI-1 and early 6128), EME-155 (PCB 30002), EME-156 (PCB Z70312), EME-156V (PCB Z80264) and the 5 V-only EME-157 (PCB Z80425). All single-sided, 40 track, 180 KB per side, 300 rpm. Secondary source.
  5. ↑ "Changing the drive belt", CPCWiki — gives the replacement belt as 3 mm wide, 0.6 mm thick and 230 mm outer circumference (commonly advertised as 115 mm), with the removal procedure. Secondary source; Amstrad published no belt dimensions.


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