27C256R EPROM - Spectrum 128 etc

• When programmed, this chip is suitable as a replacement ROM chip in the Spectrum 128, +2 (simply remove the Spectrum 128's boot ROM* from its socket and replace it with this EPROM - no PCB mods are required.) The boot rom is IC5 in the "Toastrack" Spectrum 128, IC8 in the grey +2 and IC7 in the black +2A
• I'm happy to burn whatever 32KB ROM image you need onto the chip before dispatch - Please send the ROM file after purchase (reply to the order acknowledgement email with an attachment). Or specify "BLANK" in the Special Instructions box at checkout if you have your own EPROM burner.  
• Note: Chip is an OTP (one time programmable) 28-pin 70ns 27C256R -  it cannot be erased and re-programmed. 
• This chip cannot be used in the original 16/48K Spectrum without modifying its PCB.

41464 / 4464 RAM Chip

• Organization: 64K x 4, Speed 120ns, Package: 18 pin DIL
• New, old stock (not desoldered) - all tested before dispatch.
• As used on late revision motherboards of Commodore 64, Spectrum +2A/+2B/+3 
• Depending on stock, "4464" types may be supplied - these are the same RAM chips but with a different part number.

4164 Spectrum "Upper RAM" Chip

• Organization: 64K x 1, Speed: 150ns or faster, 128-cycle refresh, Package: 16 pin DIL
• Unused, old stock parts. Good clean condition and tested for 2 hours before dispatch.
• Can be used individually or in any quantity to replace any of the original Upper RAM chips used in the Spectrum 48K (eg: Texas Instrumenents TMS4532-15NL3, TMS4532-15NL4,  OKI M3732H-20, M3732L-20). Any valid setting of the Spectrum RAM type jumpers is fine when using these chips (please see this page for more info regarding the Spectrum's Upper RAM.)
• These chips cannot be (directly) used to replace the "4116" chips used for the LOWER 16KB of RAM in the bottom left of the Spectrum's PCB.
• Also suitable for the C64, Spectrum 128 and grey 128 +2 (but not the +2A or +3)

74LS04 Logic Inverter IC

• As used in Issue 6A Spectrum motherboards and also on some models of Spectrum 128
• Brand new

74LS157 IC (Texas Instruments)

• Logic IC used in the ZX Spectrum (multiplexor chip at IC3/4 and IC25/26) and in some models of Spectrum 128

74LS174 logic IC

• As used in the  Spectrum128 (for latching Port $7ffd)
• New old stock chip - tested.

74S04 hex inverter IC (20mA outputs)

• As used in the Spectrum 128 (Toastrack) oscillator circuit
• New, old stock - tested: OK

78S05 5 Volt Regulator for Spectrum 128+2

• This is the higher power (2 Amp) version of the 7805 regulator as required by the 128+2

AY -3-8912 Sound Chip - Desoldered

• Tested - 3 tones, 3 noise, mix, polyphonic, envelope - All OK
• De-soldered part, however the pins are long, straight and clean

Diagnostic Test ROM Chip for the Spectrum 128 / +2

• Simply remove the Spectrum 128's boot ROM* from its socket and replace it with this EPROM to run diagnostic tests - no PCB mods are required. The boot rom is IC5 in the "Toastrack" Spectrum 128, IC8 in the grey +2 and IC7 in the black +2A
• Naturally, the machine needs to have a working CPU / ULA for the diagnostic code to run but it can at least identify bad RAM etc.
• The diagnostic ROM programmed onto the chip is Brendan Alford's "ZX Diagnostics" 
• Note: Chip is a OTP (one time programmable) 27C256R - so it cannot be erased and re-programmed. It cannot be used in the original 16/48K Spectrum without modifying its PCB.

Diagnostic ROM Module for Spectrum 128s

• Same module as the switchable 128 ROM replacement (listed below), just programmed with Brendan Alford's ZX Diagnostic in one slot and Retroleum DiagROM in the other.

GAL16V8-15 programmed with Unrainer for Spectrum 128s

• This corrects the bug in the 128's memory controller chip detailed here whereby certain 128 games have onscreen video disruption on the +2 (eg: Robocop 3) and the BASIC command PRINT IN 32765 causes a crash.
• The GAL chip is supplied with a 20-pin DIL socket, wire and instructions.

Memory Controller (Contention logic) GAL chip (HAL10H8ACN / PL10H8SAQ/NC)  for Spectrum 128 +2

• Original, de-soldered and tested part.
• See elsewhere in this section for a replacement GAL chip/mod that corrects a bug which manifests as video corruption in certain 128 games.

Original Spectrum 128+2 ROM - Amstrad 40054

• Extracted from a socket (not soldered) and tested - working fine (boot and checksums)
• When fitting remember the 128+2 has the chips orientated "upside down" (ie, pin 1 is at the bottom left)

PCF1306P Chip - Desoldered

• As used on the issue 6A Spectrum PCB and some Spectrum 128s (same as ZX8401)
• This is a de-soldered part, however the pins are long, straight and clean
• Tested by running diags for 1 hour - no problems encountered.

MuRata OKI Switch Mode 5v Regulator for Spectrum 128 "Toast Rack"

A replacement for the cheap inefficient 7805 used in the Spectrum 128 "Toastrack". This high-efficiency switch mode regulator wastes very little power as heat so no heatsink connection is required. It mounts directly onto the PCB where the 7805-connector wires are soldered.

• High efficiency 5v 1.5A output
• Short circuit protection
• Over current shutdown
• Over temperature shutdown
• Unmodified for direct-PCB vertical mounting in Toastrack Spectrum (instructions included).
• Can also be used in the standard Spectrum48, but as this version of the MuRata regulator is unmodified it cannot be used on Spectrum48 Issue2 boards (in a rubber-key case) as the regulator must be horizontally mounted due to space constraints. (See the Spectrum Mods section for a version modded for horizontal mounting.)

Switchable Replacement ROM Module for Spectrum 128s

• Can hold two 32KB ROM images, selected using a small onboard switch (when fitted in Spectrum 128 +2 this is accessible from the expansion port). Can be used as a Diagnostic ROM when, for example, Brendan Alford's ZX Diags is chosen as one of the ROMs.
• No PCB modifications are required when using this module - you can unplug the existing ROM chip (it's nearly always in socket) and replace it with this unit (the boot rom is IC5 in the "Toastrack" Spectrum 128, IC8 in the grey +2 and IC7 in the black +2A)
• Module has medium size round pins so as not to over-stress DIL sockets.
• Please let me know which ROM images you require programmed onto the unit using the Special Instructions box during checkout, or email me afterwards.
• Please note: The module cannot be supplied blank because it requires a special interface for the EPROM burner.
• Can also be used in practically any board that will take a 27C256 32KB EPROM (note: not compatible with the 16/48K Spectrum - I have a module tailored to its PCB in the Spectrum chips section).

TEA2000 Video Encoder IC

• As used in the Spectrum 128 +2 etc
• Symptoms when the IC is faulty include no video, monochrome only video.

Traco 2 Amp 5 Volt switching regulator TSR 2-2450

• Cool running power regulator capable of delivering 5 volts @ 2 Amps
• Replaces the L78S05 regulator header in the Spectrum 128+2 (solder direct to PCB)
• Large heatsink no longer needed.
• Pin out / fitting diagram included.