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Spare parts for Commodore 64, ZX Spectrum and more!

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Spectrum Chips

Various ICs as used in the Sinclair ZX Spectrum. All chips are new, unused unless stated.

Products:

Click on the product thumbnail for an enlarged view.

4116 Spectrum "Lower RAM" Chip

4116 RAM (150ns) chips used for Lower RAM in ZX Spectrum (and in other machines such as the TI-99/4A)
Good condition, never soldered and tested for 2 hours before dispatch in a Spectrum running memory test.

The 48K and 16K Spectrum uses eight 4116 chips for the lower 16KB of RAM. A chip can fail quite readily (especially following edge-connector related mishaps) - usually causing the Spectrum to not initialize on power up (often with the classic dead-Spectrum vertical black+white columns / flashing attribute blocks display).

Sometimes a bad chip can be detected simply by its temperature - if it is noticeably warmer than those around it, it will be highly suspect. Another crude but often effective test is to "piggy-back" a working chip on each RAM chip one at a time. If the error goes away or at least changes, there's a good chance that chip is faulty.

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)

74HCT00 Logic IC

A modern lower power replacement for the 74LS00 logic IC in the ZX Spectrum

74HCT157 IC

A modern lower power replacement for the 74LS157 logic IC for ZX Spectrum IC25/IC26 (it's probably best to stick with the original 74LS157 types for IC3/4 as the timing there can be critical).

74HCT32 Logic IC

A modern lower power replacement for the 74LS32 Logic IC in the ZX Spectrum

74LS00 Logic IC

Replacement logic IC for the ZX Spectrum (Quad NAND gate at IC24)

74LS04 Logic Inverter IC

As used in Issue 6A Spectrum motherboards and also on some models of Spectrum 128
When the 74LS04 is faulty, issues such as the Spectrum only seeing 16K occur
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

74LS32 Logic IC

Logic IC for the ZX Spectrum (Quad OR gate at IC23)

7805 Voltage Regulator

Replacement 5 volt regulator IC for the Spectrum, (breadbin) Commodore 64, ZX81 etc

Diagnostic ROM Module for Spectrum 16/48

Diagnostic Test ROM for Spectrum 16/48

Essentially the same as Switchable ROM Module (below), but supplied as standard with two different diagnostic programs installed (selected via a switch): Retroleum DiagROM and Brendan Alford's ZX Diagnostics.
If the Spectrum PCB has a chip socket for the ROM you can simply swap the chip for this module to test the PCB, no modifications are required.
A 28 pin DIL socket is supplied for where it is necessary to de-solder the ROM chip.
This module has narrow pins so will not force the socket contacts open beyond their design specs.
Please note: The module cannot be supplied blank because it requires a special interface for the EPROM burner.
I have a simple external ROM board in the Peripherals section should that be preferable.

LM1889N Video Encoder IC

LM1889N Chip, as used in ZX Spectrum for colour encoding.
Old stock parts - all tested by myself.
Never soldered. Clean, straight pins.

Nebula - A Spectrum 16/48 ULA Replacement Module

A plug-in PCB module designed to replace the ULA chip found in UK Spectrum 16/48 motherboards (versions 2 to 6) - Here's some fitting notes. Further info can be found here.
Includes a new 40-pin DIL socket, just in case the original is worn/unsuitable.

RAM upgrade kit - To upgrade a 16KB Spectrum to 48K

RAM Upgrade Kit for 16K ZX Spectrum (to 48K)

Comprises:

8 x 4164 Upper RAM chips (Unused, old stock chips - all tested by myself.)

.. brand new support logic chips for the upper RAM:

2 x 74HCT157
1 x 74HCT32
1 x 74HCT00

.. and wire links / solder, and printed instructions.

Fitting is usually just a case of inserting the chips into the empty sockets on the motherboard and soldering a couple of wire links across the appropriate pads on the PCB. Almost all 16K models can be upgraded but there are some very early (Issue One) Spectrums that have no space on the PCB for more memory.

RAM upgrade kit for 16KB Spectrum (to 48K) - Module version

RAM Upgrade Kit for 16K ZX Spectrum (to 48K) - Module Version.

This version of the Spectrum RAM upgrade kit offers a cheaper, modern alternative to using individual DRAM chips. A small custom daughterboard module with a low power SRAM IC is simply pressed into the RAM IC sockets.

The kit also contains the 4 support logic chips which must be fitted at positions IC23-26 (IE: 2 x 74HCT157, 1 x 74HCT32 and1 x 74HCT00). A couple of wire links may also need to be soldered between the appropriate pads located on the PCB - full fitting instructions are provided.

Please check your Spectrum can be actually upgraded! Almost all 16K models can but there are some very early Spectrums that have no space on the PCB for more memory.

Click here for fitting instructions (printed version also included in kit)

If you don't require the support logic, the board is usually available on its own - see below.

ROM Replacement Module for 16/48K Spectrum - No PCB Mods Required

Switchable ROM Replacement Board (No PCB mods required)

For the original 16K/48K ZX Spectrum (only) - Can be installed permanently, soldered or plugged into a chip socket (a new DIL socket is supplied with the module, should it be required).
Can hold two 16K ROM images, selected using a small onboard switch which can be accessed from Spectrum's expansion port so it is not necessary to open the machine to swap ROMs.
Unlike when using a plain EPROM chip, no modifications to the Spectrum's circuitry are required when using this board - you can just desolder/unplug the existing ROM chip, replace it with this module and replace the original chip when done.
Please let me know which two ROM images you require programmed onto the unit using the Special Instructions box during checkout, or email me afterwards. If nothing is specified, I will assume you require the standard ROM in slot A and DiagROM in slot B.
Please note: The module cannot be supplied blank because it requires a special interface for the EPROM burner.

Lower RAM replacement module for ZX Spectrum

A PCB module designed to replace (all 8) of the 4116 ICs used for the lower 16KB of RAM in the Spectrum.

Upper RAM replacement module for ZX Spectrum

A PCB module designed to replace (all 8) of the 4532 ICs used for the upper 32KB of RAM in the Spectrum.

Suitable for Spectrum motherboard issues 2-6
Modern low power SRAM
Can be pressed into DIL sockets or soldered onto Spectrum PCB when the 4532s have been removed.
Click here for fitting instructions - printed version also included with board.

Please note: If you need to upgrade a 16KB machine with this board, please purchase the version with the support logic chips (or order 1 x 74HCT00, 1 x 74HCT32, 2 x 74HCT157 in addition to this board)

Z80 CPU - New

Brand new Zilog Z80 Central Processing Unit for Spectrum (and ZX81, Amstrad CPC etc)
Modern lower-power CMOS version, direct replacement for NMOS originals.
Replacing the CPU also resolves the known issue with out-of-spec Z80s sometimes found in Spectrums. (ie: external interfaces not working correctly due to weak signals, usually "M1")

Z80 CPU - Original, NMOS type - New, old stock part

Genuine vintage 4MHz NMOS Z80 chip from 1988 made by Goldstar - NOT a re-marked modern fake
Has never been soldered
Tested, working (/M1 signal good too)