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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...
Link the hosted dk'tronics Peripheral Technical Manual (memory expansion and silicon disc)
 
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| name        = Amstrad CPC 664
| name        = Amstrad CPC 664
| 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|frameless]]
| caption      = Amstrad CPC 664 with the CTM644 colour monitor
| caption      = CPC 664 with the CTM644 colour monitor
| developer    = Amstrad
| developer    = Amstrad
| manufacturer = Amstrad Consumer Electronics plc
| manufacturer = Amstrad Consumer Electronics plc
| type        = Home computer
| type        = Home computer
| release date = 1985
| release date = 25 April 1985
| discontinued = August 1985
| discontinued = 1985
| cpu          = Zilog Z80A @ 4 MHz
| price        = £339 with green monitor, £449 with colour monitor
| memory      = 64 KB RAM (over 41 KB available to the user)
| cpu          = Zilog Z80A at 4 MHz
| rom          = 32 KB OS and Locomotive BASIC 1.1, plus a 16 KB AMSDOS ROM
| memory      = 64 KB RAM
| storage      = Built-in 3-inch single-sided disc drive, Matsushita EME-150A
| rom          = 32 KB (operating system and Locomotive BASIC 1.1), 16 KB AMSDOS ROM
| display      = 160×200×16, 320×200×4 or 640×200×2 from a 27-colour palette
| storage      = Built-in 3-inch disc drive
| display      = 160 × 200 (16 colours), 320 × 200 (4) or 640 × 200 (2) from 27
| sound        = General Instrument AY-3-8912, three voices
| sound        = General Instrument AY-3-8912, three voices
| power        = 5 V DC and a separate 12 V disc feed, both from the monitor
| power        = 5 V and 12 V DC from the monitor
| os          = Amstrad firmware, Locomotive BASIC 1.1, AMSDOS, CP/M 2.2
| os          = Amstrad firmware, Locomotive BASIC 1.1, AMSDOS, CP/M 2.2
| predecessor  = [[Amstrad CPC 464]]
| predecessor  = [[Amstrad CPC 464]]
| successor    = [[Amstrad 6128|Amstrad CPC 6128]]
| model        = CPC 664
| model        = CPC 664
}}
}}
<templatestyles src="Template:StyledTable/styles.css" />
<templatestyles src="Template:StyledTable/styles.css" />
The '''Amstrad CPC 664''' is the second model of the Amstrad CPC range. It keeps the 64 KB of RAM of the [[Amstrad CPC 464]] but replaces the cassette deck with a built-in 3-inch disc drive, and it has Locomotive BASIC 1.1. It was introduced in the UK on 25 April 1985 at £339 with a green monitor or £449 with a colour monitor, and was made for only about six months: when the CPC 6128 reached Europe on 15 August 1985, Amstrad dropped the 664.<ref name="wpcpc">Wikipedia, [https://en.wikipedia.org/wiki/Amstrad_CPC "Amstrad CPC"], sections "CPC 664", "CPC 6128" and "Schneider CPC". Retrieved 2026-10-01. Gives the 664's introduction date and prices, its short production run, the 6128's European launch date and the Schneider distribution in German-speaking Europe.</ref> In Germany, Austria and Switzerland it was sold as the Schneider CPC 664, with grey keys.<ref name="wpcpc" />


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.
== Power ==


'''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.
Like the 464, the CPC 664 has no mains connection and no power supply of its own, but it needs two DC feeds. Amstrad's specification lists a 5&nbsp;mm socket for the 5&nbsp;V supply from the monitor and a 5&nbsp;mm plug and lead that goes to the 12&nbsp;V disc power socket on the monitor. The power supply entry reads "Screen System: 240V AC 50Hz (keyboard and disc drive power supplied by screen system)".<ref name="sm664spec">Amstrad Consumer Electronics plc, ''CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual'', back page "CPC664 Technical Specification". Described at [[Amstrad CPC 664 Service Manual]].</ref> The CTM644 colour monitor and the GT65 green monitor provide both rails. In the parts list the DC jack is J301 and the 12&nbsp;V cord CD301; the 5-pin DIN socket J302 is for an external cassette recorder, not power.<ref name="sm664pl">Amstrad Consumer Electronics plc, ''CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual'', p. 21 "Electrical Parts List CPC664". Described at [[Amstrad CPC 664 Service Manual]].</ref> The monitors contain the mains supply and a CRT; see [[CRT Discharge Procedure]].


'''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>
== Hardware ==


== The monitor is the power supply ==
Amstrad's specification lists a Z80A at 4&nbsp;MHz, 64 KB of RAM with over 41 KB available to the user, 32 KB of ROM for BASIC and the operating system, a 6845 CRT controller, an AY-3-8912 sound chip (three voices, eight octaves), an 8255 parallel interface and 74 keys.<ref name="sm664spec" /> The parts list names:<ref name="sm664pl" />


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.
* IC111, Z8400APS (Z80A CPU)
* IC103, TMM-23256P-1952, Amstrad part 40022 (system ROM)
* IC204, TMM-23128P-1951, part 40015 (AMSDOS ROM)
* IC116, HSG3130/3170, part 40010 (gate array)
* IC108, HD6845SP; IC107, M5L8255AP-5; IC102, AY-3-8912
* IC117–124, eight HM4864U-2 DRAMs
* IC201, µPD765AC disc controller; IC202, FDC9216BT data separator
* IC301, LA4140, and IC302, LA63585, with relay RY301, for the cassette interface


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" />
Part 40012 in the same list is IC211, a 74LS27, not a ROM.<ref name="sm664pl" />


'''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 screen modes are the same as the 464's: 160 × 200 in 16 colours, 320 × 200 in 4 and 640 × 200 in 2, from a palette of 27.<ref name="sm664spec" />


'''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.
=== Main board ===


== Board ==
The CPC 664 has a single main board, Z70205, 475 × 155&nbsp;mm, seen in two versions.<ref name="cpcwikimb">CPCWiki, [https://www.cpcwiki.eu/index.php/Mainboard_Versions "Mainboard Versions"]. Retrieved 2026-10-01. Community catalogue of board markings and per-version changes, compiled from photographed boards.</ref> MC0005A has an 8-pin data separator. MC0005B is found in German Schneider machines and usually carries a patch resistor between pin 9 (A0) and pin 14 (/CASADDR) of IC105; it is R160 in the schematic but has no legend on the board, so it is a factory addition, not a previous owner's repair.<ref name="cpcwikimb" /> The CPC 464 boards are listed on [[Amstrad CPC 464#Main board versions|the CPC 464 page]].


The CPC 664 main board is '''Z70205''', 475 × 155 mm, in two variants:<ref name="cpcwikimb" />
== Disc drive ==


{| class="wikitable styled-table" style="width:95%; text-align:left;"
Amstrad's specification describes a 3-inch drive "conforming to the Hitachi/Panasonic standard", with the software set for a 12&nbsp;ms step rate and 30&nbsp;ms settling time, and a second-drive socket; the system controls at most two drives.<ref name="sm664spec" /> The mechanism is a Matsushita EME-150A with its own board, PCB 30001. On this model the spindle speed is set with VR201 on that board; the 3-inch drives turn at 300&nbsp;rpm, a 200&nbsp;ms index period.<ref name="cpcfdd">CPCWiki, [https://www.cpcwiki.eu/index.php/Amstrad_FDD_part "Amstrad FDD part"]. Retrieved 2026-10-01. Lists the Matsushita mechanisms Amstrad used (EME-150A on PCB 30001 in the CPC 664 and early DDI-1 and 6128, then EME-155, EME-156, EME-156V and EME-157), their common characteristics, and speed adjustment.</ref> Amstrad's flow chart gives the same target: adjust with VR201 to 200 ±1&nbsp;ms.<ref name="sm664fc">Amstrad Consumer Electronics plc, ''CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual'', pp. 8–11 "Diagnostic Flow Chart" and p. 12 "Alignment Checks". Described at [[Amstrad CPC 664 Service Manual]].</ref>
|+'''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.'''<ref name="cpcwikimb" /> If your board is marked Z70200, you are looking at a 464.
 
== Devices ==
 
Amstrad's own parts list:<ref name="sm664" />
 
{| 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
|}
 
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.<ref name="sm664" />
* '''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" />
 
'''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 disc drive ==
 
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.
 
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" />


=== Disc formats ===
The drive is single-sided, 40 tracks; the user turns the disc over to use the other side, and each side has its own write-protect clip.<ref name="sm664spec" /> AMSDOS and CP/M share three formats:<ref name="sm664spec" />


Amstrad's own figures. All are single-sided, double density, 512-byte sectors, 40 tracks, 2:1 interleave:<ref name="sm664" />
{| class="wikitable styled-table" style="width:75%; text-align:left;"
 
|+'''CPC 664 disc formats'''
{| class="wikitable styled-table" style="width:85%; text-align:left;"
|+'''AMSDOS disc formats'''
! Format !! Sectors per track !! Reserved tracks !! Capacity
! Format !! Sectors per track !! Reserved tracks !! Capacity
|-
|-
| '''SYSTEM''' || 9 || 2 || '''169 KB'''
| SYSTEM || 9 || 2 || 169K
|-
| '''DATA''' || 9 || none || '''178 KB'''
|-
| '''IBM''' || 8 || 1 || '''154 KB'''
|}
 
=== The drive belt ===
 
'''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.<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 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]].
 
=== Amstrad's position on the mechanism ===
 
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.
 
== Display ==
 
The same video subsystem as the 464: 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
| DATA only || 9 || none || 178K
|-
|-
| 2 || 640 × 200 || 2 || 80 columns
| IBM || 8 || 1 || 154K
|}
|}


'''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.
The drive belt is the usual cause of a drive that runs its motor without turning the disc. CPCWiki gives the replacement belt as 3&nbsp;mm wide, 0.6&nbsp;mm thick and 230&nbsp;mm in outer circumference, often sold as "115&nbsp;mm".<ref name="cpcbelt">CPCWiki, [https://www.cpcwiki.eu/index.php/Changing_the_drive_belt "Changing the drive belt"]. Retrieved 2026-10-01. Gives the belt size and a removal procedure for the CPC 6128, which it says is nearly the same on other CPCs and the DDI-1.</ref> Amstrad's manual marks its drive alignment pages for information only: "Service Agents must not carry out any repair or adjustment to the Drive mechanism and its associated PCB 30001 during warranty."<ref name="sm664fc" /> The [[Amstrad CPC 664 Maintenance Guide]] covers the belt and the speed adjustment.


== Amstrad's published specification ==
== Specification ==


{| class="wikitable styled-table" style="width:90%; text-align:left;"
{| class="wikitable styled-table" style="width:80%; text-align:left;"
|+'''CPC 664 — from Amstrad's specification page'''<ref name="sm664" />
|+'''CPC 664, from Amstrad's specification page'''<ref name="sm664spec" />
! Item !! Figure
! Item !! Figure
|-
|-
| Processor || Z80A at 4 MHz
| Processor || Z80A at 4&nbsp;MHz
|-
|-
| RAM / ROM || 64 KB RAM (over 41 KB available to the user) / 32 KB ROM for BASIC and OS
| Memory || 64K RAM (over 41K available to the user); 32K ROM for BASIC and OS
|-
|-
| Video / sound / I/O || 6845 CRT controller · AY-3-8912, 3 voice, 8 octave · 8255 parallel I/O
| Expansion || Up to 252 additional 16K ROMs
|-
|-
| Keyboard || 74 keys
| Keyboard unit || 580 × 70 × 170&nbsp;mm, 2.4&nbsp;kg
|-
|-
| Disc drive || 3 inch, 12 ms step rate, 30 ms settling time, maximum 2 drives
| CTM644 monitor || 375 × 340 × 365&nbsp;mm, 10.6&nbsp;kg
|-
|-
| Expansion || Up to 252 additional 16 KB ROMs
| GT65 monitor || 305 × 315 × 335&nbsp;mm, 6.3&nbsp;kg
|-
|-
| Keyboard unit || 580 × 70 × 170 mm, 2.4 kg
| Mains || 240&nbsp;V AC 50&nbsp;Hz, at the monitor
|-
| 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 ==
== Documentation ==
 
* [[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 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.
* [[Amstrad CPC 664 Service Manual]] – Amstrad's service manual for the CPC 664, CTM644 and GT65
* [[Amstrad Peripheral Technical Manual (Edition 2)]] – dk'tronics' 1986 manual for its own CPC add-ons (lightpen, speech synthesiser, 64K and 256K memory expansions and silicon discs), including how the expansion RAM is banked through the gate array port at &7F00; not an Amstrad document


== Gallery ==
== Gallery ==
<gallery mode="packed" heights="200">
<gallery mode="packed" heights="200">
File:Amstrad CPC 664 with colour monitor.jpg|CPC 664 with the CTM644 colour monitor
File:Amstrad CPC 664 with colour monitor.jpg|CPC 664 with the CTM644 colour monitor
File:Amstrad CPC 664 ordinateur.jpg|The disc drive bay
File:Amstrad CPC 664 ordinateur.jpg|The keyboard unit and disc drive
File:Amstrad CPC 664 product photo.jpg|1985 catalogue photograph
File:Amstrad CPC 664 product photo.jpg|CPC 664 in a 1985 catalogue photograph
File:Amstrad CPC664 main PCB layout.jpg|Main PCB layout from Amstrad's service manual
</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]] · [[Amstrad 6128]]
* [[CRT Discharge Procedure]]
* [[CRT Discharge Procedure]]


Latest revision as of 17:56, 1 October 2026

Amstrad CPC 664
CPC 664 with the CTM644 colour monitor
Specifications
DeveloperAmstrad
ManufacturerAmstrad Consumer Electronics plc
TypeHome computer
Released25 April 1985
Discontinued1985
Intro price£339 with green monitor, £449 with colour monitor
CPUZilog Z80A at 4 MHz
Memory64 KB RAM
StorageBuilt-in 3-inch disc drive
Display160 × 200 (16 colours), 320 × 200 (4) or 640 × 200 (2) from 27
SoundGeneral Instrument AY-3-8912, three voices
ROM32 KB (operating system and Locomotive BASIC 1.1), 16 KB AMSDOS ROM
Power5 V and 12 V DC from the monitor
OS / FirmwareAmstrad firmware, Locomotive BASIC 1.1, AMSDOS, CP/M 2.2
PredecessorAmstrad CPC 464
SuccessorAmstrad CPC 6128
Model no.CPC 664

The Amstrad CPC 664 is the second model of the Amstrad CPC range. It keeps the 64 KB of RAM of the Amstrad CPC 464 but replaces the cassette deck with a built-in 3-inch disc drive, and it has Locomotive BASIC 1.1. It was introduced in the UK on 25 April 1985 at £339 with a green monitor or £449 with a colour monitor, and was made for only about six months: when the CPC 6128 reached Europe on 15 August 1985, Amstrad dropped the 664.[1] In Germany, Austria and Switzerland it was sold as the Schneider CPC 664, with grey keys.[1]

Power

[edit | edit source]

Like the 464, the CPC 664 has no mains connection and no power supply of its own, but it needs two DC feeds. Amstrad's specification lists a 5 mm socket for the 5 V supply from the monitor and a 5 mm plug and lead that goes to the 12 V disc power socket on the monitor. The power supply entry reads "Screen System: 240V AC 50Hz (keyboard and disc drive power supplied by screen system)".[2] The CTM644 colour monitor and the GT65 green monitor provide both rails. In the parts list the DC jack is J301 and the 12 V cord CD301; the 5-pin DIN socket J302 is for an external cassette recorder, not power.[3] The monitors contain the mains supply and a CRT; see CRT Discharge Procedure.

Hardware

[edit | edit source]

Amstrad's specification lists a Z80A at 4 MHz, 64 KB of RAM with over 41 KB available to the user, 32 KB of ROM for BASIC and the operating system, a 6845 CRT controller, an AY-3-8912 sound chip (three voices, eight octaves), an 8255 parallel interface and 74 keys.[2] The parts list names:[3]

  • IC111, Z8400APS (Z80A CPU)
  • IC103, TMM-23256P-1952, Amstrad part 40022 (system ROM)
  • IC204, TMM-23128P-1951, part 40015 (AMSDOS ROM)
  • IC116, HSG3130/3170, part 40010 (gate array)
  • IC108, HD6845SP; IC107, M5L8255AP-5; IC102, AY-3-8912
  • IC117–124, eight HM4864U-2 DRAMs
  • IC201, µPD765AC disc controller; IC202, FDC9216BT data separator
  • IC301, LA4140, and IC302, LA63585, with relay RY301, for the cassette interface

Part 40012 in the same list is IC211, a 74LS27, not a ROM.[3]

The screen modes are the same as the 464's: 160 × 200 in 16 colours, 320 × 200 in 4 and 640 × 200 in 2, from a palette of 27.[2]

Main board

[edit | edit source]

The CPC 664 has a single main board, Z70205, 475 × 155 mm, seen in two versions.[4] MC0005A has an 8-pin data separator. MC0005B is found in German Schneider machines and usually carries a patch resistor between pin 9 (A0) and pin 14 (/CASADDR) of IC105; it is R160 in the schematic but has no legend on the board, so it is a factory addition, not a previous owner's repair.[4] The CPC 464 boards are listed on the CPC 464 page.

Disc drive

[edit | edit source]

Amstrad's specification describes a 3-inch drive "conforming to the Hitachi/Panasonic standard", with the software set for a 12 ms step rate and 30 ms settling time, and a second-drive socket; the system controls at most two drives.[2] The mechanism is a Matsushita EME-150A with its own board, PCB 30001. On this model the spindle speed is set with VR201 on that board; the 3-inch drives turn at 300 rpm, a 200 ms index period.[5] Amstrad's flow chart gives the same target: adjust with VR201 to 200 ±1 ms.[6]

The drive is single-sided, 40 tracks; the user turns the disc over to use the other side, and each side has its own write-protect clip.[2] AMSDOS and CP/M share three formats:[2]

CPC 664 disc formats
Format Sectors per track Reserved tracks Capacity
SYSTEM 9 2 169K
DATA only 9 none 178K
IBM 8 1 154K

The drive belt is the usual cause of a drive that runs its motor without turning the disc. CPCWiki gives the replacement belt as 3 mm wide, 0.6 mm thick and 230 mm in outer circumference, often sold as "115 mm".[7] Amstrad's manual marks its drive alignment pages for information only: "Service Agents must not carry out any repair or adjustment to the Drive mechanism and its associated PCB 30001 during warranty."[6] The Amstrad CPC 664 Maintenance Guide covers the belt and the speed adjustment.

Specification

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CPC 664, from Amstrad's specification page[2]
Item Figure
Processor Z80A at 4 MHz
Memory 64K RAM (over 41K available to the user); 32K ROM for BASIC and OS
Expansion Up to 252 additional 16K 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

Documentation

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  • CPC 664 with the CTM644 colour monitor
    CPC 664 with the CTM644 colour monitor
  • The keyboard unit and disc drive
    The keyboard unit and disc drive
  • CPC 664 in a 1985 catalogue photograph
    CPC 664 in a 1985 catalogue photograph
  • Main PCB layout from Amstrad's service manual
    Main PCB layout from Amstrad's service manual
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References

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  1. ↑ 1.0 1.1 Wikipedia, "Amstrad CPC", sections "CPC 664", "CPC 6128" and "Schneider CPC". Retrieved 2026-10-01. Gives the 664's introduction date and prices, its short production run, the 6128's European launch date and the Schneider distribution in German-speaking Europe.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Amstrad Consumer Electronics plc, CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual, back page "CPC664 Technical Specification". Described at Amstrad CPC 664 Service Manual.
  3. ↑ 3.0 3.1 3.2 Amstrad Consumer Electronics plc, CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual, p. 21 "Electrical Parts List CPC664". Described at Amstrad CPC 664 Service Manual.
  4. ↑ 4.0 4.1 CPCWiki, "Mainboard Versions". Retrieved 2026-10-01. Community catalogue of board markings and per-version changes, compiled from photographed boards.
  5. ↑ CPCWiki, "Amstrad FDD part". Retrieved 2026-10-01. Lists the Matsushita mechanisms Amstrad used (EME-150A on PCB 30001 in the CPC 664 and early DDI-1 and 6128, then EME-155, EME-156, EME-156V and EME-157), their common characteristics, and speed adjustment.
  6. ↑ 6.0 6.1 Amstrad Consumer Electronics plc, CPC664 Micro Computer / CTM644 Colour Monitor / GT65 Green Monitor Service Manual, pp. 8–11 "Diagnostic Flow Chart" and p. 12 "Alignment Checks". Described at Amstrad CPC 664 Service Manual.
  7. ↑ CPCWiki, "Changing the drive belt". Retrieved 2026-10-01. Gives the belt size and a removal procedure for the CPC 6128, which it says is nearly the same on other CPCs and the DDI-1.


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