The Memotech Library

Technical Data for the MTX Series

Component Data Sheets

There are many sources for component datasheets on the internet, including the manufacturers, component suppliers and colleges/universities, so most datasheets are easy enough to find with a quick "Google". However, the components used in the Memotech range are now very old and mostly obsolete, so datasheets are sometimes very hard, if not impossible, to find. I have spent a lot of time trying to find datasheets for these obscure components, sometimes successfully and sometimes not. I have posted them here in case they are useful to others, if you have copies of any of the ones highlighted that I don't have, I would appreciate a copy or link to them. This page is a work in progress, I do have a few other datasheets that I will be adding shortly.

Note: Most of the "alternative" components listed below are based on datasheets that I found when looking for those of the original Memotech suppliers. On comparing these datasheets with the originals, I believe them to be compatible, apart from a couple of exceptions, as indicated below, I have not actually tried them - if you can't find the original components, you might like to try the suggested alternatives - at your own risk of course :-) Components indicated like this, are not likely to be compatible with the MTX.

The more significant components such as floppy disk controller and CRT controller ICs are discussed on various pages on the site. Other components are not specifically referenced, but this page will eventually be a placeholder for all ICs and major components used in the MTX series of computers.

My interest in this data relates to its use in the Memotech MTX series of computers and related hardware, this means that for me, the most useful data sheets are from that period and are almost certainly not the most current, if you are looking for up to date information, the datasheets here will likely have been superseded.

Most of this information comes from long defunct publications, I don't imagine that the copyright holders, are vaguely interested in these pages, but if anyone has issues with me making this information available, let me know and I will remove the offending item(s).

A word about quality : these datasheets come from a range of sources and while all are easily readable, some have rather better quality than others. If you have better copies than I have posted here, if you send me a copy, I will update the site.

• MTX Computer Board RAM
• MTX Computer Board VRAM
• MTX Computer Board ROM
• Generic 74 Series Logic
• Application Specific

MTX Computer Board Dynamic RAM (Original : OKI 3764-20)
Extract from the OKI Data Book showing 3764 compatibility with some other DRAMs, click image to see complete table
Click to open PDF	Generic Designation	Manufacturer	Manufacturer's Designation	Comments
	4164	OKI	(MS)M3764-20RS	RAM (MTX512/RS128)
	4164	Hitachi	HM4864A-3	OKI Cross Reference for 3764
	4164	Texas Instruments	TMS4164A-20	OKI Cross Reference for 3764
	4164	Motorola	MCM6665A-20	OKI Cross Reference for 3764
	4164	NEC	uPD4164A-2	OKI Cross Reference for 3764
	4164	Mitsubishi	M5K4164A-20	OKI Cross Reference for 3764
	4164	Fujitsu	MB8264A-20	OKI Cross Reference for 3764
	4164	Motorola Semiconductors	MCM4164CP	(A possible alternative)
	4164	Samsung	KM4164B	(A possible alternative)

 

 

MTX512S2 Computer Board Dynamic RAM (Original : Various, including . . . ) read this
Click to open PDF	Generic Designation	Manufacturer	Manufacturer's Designation	Comments
	41256	Hitachi	HM51256-15	In my Video Wall MTX512S2
	41256   Timing data  only	NEC	uPD41256C-15	In my non-Video Wall MTX512S2
	41256	NEC	uPD41256C-10	(An alternative to the NEC component)
	41256	Texas Instruments	TMS41256-10	In my Video Wall Reflex
	41256	OKI	MSM41256A	(Not seen used, should be compatible)

 

 

MTX Computer Board Video RAM (Original : ITT 4116 3N)
Click to open PDF	Generic Designation	Manufacturer	Manufacturer's Designation	Comments
	4116	ITT	4116 3N	Video RAM (All models)
	4116	AMD	AM9016	(An alternative to the ITT component)
	4116	Mostek	MK4116P	(An alternative to the ITT component)
	4116	Motorola	MCM4116A	(An alternative to the ITT component)
	4116	Texas Instruments	TMS4116	(An alternative to the ITT component)

 

 

ROMs
Click to open PDF	Generic Designation	Manufacturer	Manufacturer's Designation	Comments
	3864	OKI	M3864-06	8k (64k x 1) Mask ROM
	2764	Mitsubishi Electric	M5L2764K-2	(An EPROM alternative to the ROM)
	2764	ST Microelectronics	M2764A	(An EPROM alternative to the ROM)
	2564	Texas Instruments	TMS2564	(Unusual ROM seen at Memofest)
	38128	OKI	M38128	16k (128k x 1) Mask ROM
	27128	ST Microelectronics	M27128	(An EPROM alternative to the ROM)
	27128	NEC	uPD27128	(An EPROM alternative to the ROM)

 

 

74 Series Logic (Originals : Predominantly Texas Instruments)     74 Series Nomenclature
Click to open PDF	Generic Designation	Manufacturer	Manufacturer's Designation	Comments
	74LS00	Texas Instruments	SN74LS00	Quad 2 Input NAND Gates
	74LS04	Texas Instruments	SN74LS04	Hex Inverters
	74LS08	Texas Instruments	SN74LS08	Quad 2 Input AND Gates
	74LS14	Texas Instruments	SN74LS14	Hex Schmitt Trigger Inverters
	7416	Texas Instruments	SN7416	Hex Inverter Buffers / Drivers
	74LS27	Texas Instruments	SN74LS27	Tri 3 Input NOR Gates
	74LS74	Texas Instruments	SN74LS74A	Dual flip-flops with Clear
	74LS138	Texas Instruments	SN74LS138	3 Line to 8 Line Decoder/Mux
	74LS157	Texas Instruments	SN74LS157	Quad 2 Line to 1 Line Selectors/Muxs
	74LS157	Motorola Semiconductors	SN74LS157	(An alternative to the TI component)
	74LS163	Texas Instruments	SN74LS163A	4-bit counter
	74LS163	Motorola Semiconductors	SN74LS163A	(An alternative to the TI component)
	74LS166	Texas Instruments	SN74LS166A	8-bit shift register
	74LS175	Texas Instruments	SN74LS175	Quad "D" Type flip-flops
	74LS175	Motorola Semiconductors	SN74LS175	(An alternative to the TI component)
	74LS193	Texas Instruments	SN74LS193	4-bit counter  with Clear
	74LS244	Texas Instruments	SN74LS244	Octal Buffers / Line Drivers
	74LS245	Texas Instruments	SN74LS245	Octal Bus Transceivers
	74LS273	Texas Instruments	SN74LS273	Octal "D" Type flip-flops with Clear
	74LS273	Motorola Semiconductors	SN74LS273	(An alternative to the TI component)
	74LS367	Texas Instruments	SN74LS367AN	Hex Bus Drivers
	74LS367	Fairchild Semiconductor	DM74LS367A	(An alternative to the TI component)
	74LS373	Texas Instruments	SN74LS373	Octal Transparent Latches
	74LS374	Texas Instruments	SN74LS374	Octal Edge Triggered flip-flops
	74LS374	Fairchild Semiconductor	DM74LS74A	(An alternative to the TI component)

 

Application Specific
	6116	Hitachi	HM6116P-4	Speculator 16k Static RAM (2k x 8)
	6116	IDT	IDT6116	(An alternative 2k SRAM)
	7805	Texas Instruments	LM7805C	MTX Voltage Regulator : 5VDC
	7812	Texas Instruments	LM7812C	MTX Voltage Regulator : 12VDC
	FD179x-02	Western Digital	FD179x-02	FDX/SDX05 : Floppy Disk Controller
	LM1889	National Semiconductor	LM1889	Video board : TV/Video Modulator
	MC6845	Motorola Semiconductors	MC6845	80 column board : CRT Controller
				(Info on the Amstrad CPC Wiki )
	6845	Pravetz	CM607P	Bulgarian Clone of MC6845
	6845	Thomson Semiconductors	EF6845P	Thompson Clone of MC6845
	PAL14L4	Monolithic Memories (AMD / Lattice Semi.)	PAL14L4	Various : Custom Logic Functions
	GAL16V8	Lattice Semiconductor	GAL16V8	Can be coded to replace a PAL14L4
	SN76489AN	Texas Instruments	SN76489AN	MTX Complex Sound Generator
	TIP2955	Texas Instruments	TIP2955	MTX Power Transistor : 5VDC
	TIP2955	ST Microelectroncs	TIP2955	(An alternative to the TI component)
	TMS9918A / 29A	Texas Instruments	TMS9918A	MTX Video Display Processor
	Z80	Zilog CPU Specification	Z80	MTX CPU
	Z80CTC +	Zilog Counter/Timer Chip	Z80CTC	MTX Counter / Timer
	Z80DART +	Zilog Dual Async Rx/Tx	Z80DART	RS232 Board : Communications

   + Datasheet courtesy of Paul Daniels

 

MTX512S2 - 256 k RAM

The MTX512S2 and other 256k MTX computer boards, do not use RAM from a single supplier like the 64k and 32k boards do. I know of at least three different suppliers, NEC, Hitachi and Texas Instruments. Whilst the specs that I have been able to find for the various DRAMs used would indicate that they are compatible, in practice, there seems to be some inconsistencies in the performance of one type of RAM with another in certain machines. It is not known why this should occur, but you **may** have a problem if replacing one manufacturer's RAM with another's.

I mention this because whilst I have been successful in replacing the NEC D41256C-15 RAM in my non-Video Wall MTX512S2 with NEC D41256C-10 RAM, Andy has had problems using the same RAM to replace the (unknown) RAM in his MTX512S2.