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Spare parts for Commodore 64, ZX Spectrum and more!

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Spectrum Modifications

Items for modifying Spectrum PCBs..

Products:

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3 Metres of Kynar-style PCB repair wire

Fine (0.25mm solid core) wire, useful for repairing damaged PCBs
Sold in 3 Metre lengths
Colour: Green

BC549C Transistor

A general purpose NPN transistor that can be used to make an alternative version of composite video mod on the Spectrum. Using a transistor instead of a simple wire or capacitor provides a stronger signal, usually giving a brighter picture. It also buffers the Spectrum's video circuitry so much of the load is taken by this transistor. However, it may not be compatible with modern LCD TVs.

Transistor video mod connections:

Collector (left lead in image) to 5V pad (TV modulator power, disconnect the TV modulator power wire)
Base (centre lead) to Spectrum video out pad (disconnect the TV modulator signal wire)
Emitter (right lead) to video socket - it's best to use a small piece of wire to extend this lead.

Note: Alternatively, two BC549s can be used to replace TR1 and TR2 to give a brighter picture when the composite mod is done uisng a capacitor (though they must be fitted rotated 180' compared to the silk screen legend). Please see this article for details.

Brand new

Blue axial capacitors For Spectrum 16/48 and Composite Mod Kit

Blue Axial Capacitors For ZX Spectrum & Composite Video Mod Kit

A set of new blue coloured axial type electrolytic capacitors for the Spectrum 16 / 48 / 48+ made by Cornell Dubilier (ie: Illinois Capacitor) a long established brand. (Axial caps have a wire at each end, ie: the same form as those originally fitted to the Spectrum PCB.)
This kit also includes components to modify the Spectrum's video output to give a composite video signal from the existing phono connector and parts for the DC-DC improvement mod for issue 2 boards.
Brief fitting instructions included, with full details here.
Unfortunately, the cheaper black axial caps are no longer available.

A 100uf Radial Electrolytic Capacitor

A capacitor suitable for making the composite video mod on ZX Spectrums (one of these is included in the Spectrum cap pack above).

Please see this article for details.

DC-DC mod components for Issue 3 / 3B / 4A Spectrum boards

A pack of the following components to do the DC-DC circuit modification:

1 x 1uf Axial Capactitor
1 x 22uf Axial Capactitor
2 x BA157 Diodes
1 x 1N4148 Diode
1 x 5v Zener Diode
1 x 220 Ohm Resistor
1 x 2.2K Resistor

Instructions included.

De-solder Braid / Wick (1.5 Metres x 2.5mm)

Ideal for assisting repair work on motherboards etc
Sold in sealed packs.

Flux Pen

Helps solder flow cleanly, ideal for re-work jobs etc
Will also dissolve old flux residue etc to prepare very clean solder pads.
Non-corrosive flux.
Contents: 10ml

Small Tube Of Thermally Conductive Adhesive

For attaching heatsinks to chips
5 gram tube - enough for about a dozen chips
Instructions supplied

Heatsink for 40 pin DIL Chips - Black Anodized, Bare

Heatsink for 40 Pin DIL Chips - Bare

Heatsink suitable for 40 PIN Chips such as the CPU in the Commodore 64 and ULA in ZX81 and Spectrum Plus.
Note: There is not enough room for a heatsink in the rubber-keyed Spectrum unless you desolder the ULA's IC socket and fit the ULA directly onto the motherboard. For the Spectrum+ there is room to fit the heatsink without soldering the ULA to the PCB if the keyboard backing plate is the thin grey metal type (the plastic backing plates are thicker and get in the way slightly).
Black anodized finish
Dimensions: 50mm x 19mm x 4.8mm
Attachment methods: The heatsink is not self-adhesive - it requires thermally conductive glue which I sell separately.

Heatsink for 40 pin DIL Chips - Black Anodized, Self Adhesive

Heatsink for 40 Pin DIL Chips - Self Adhesive

As above, but with thermally-conductive self-adhesive pad pre-attached, ready to peel and apply.

Large Tesa brand isopropyl alcohol wipe

Large (folds out to approx 14x18cm) 70% Isopropyl alcohol wipe
Suitable for cleaning contacts, chips/heatsinks etc
Made by Tesa, the adhesive specialists

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

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

Comprises eight RAM chips (IC15-22), four glue logic ICs (IC23-26), 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.

8 x 4164 Upper RAM chips (Unused, old stock chips in good condition - all tested by myself.)
2 x 74HCT157 (brand new)
1 x 74HCT32 ("")
1 x 74HCT00 ("")

This kit is suitable for Issue TWO and Issue 3 PCBs (the 16K Spectrum had been discontinued beyond those board revisions. Issue One Spectrums required a special daughter board to upgrade its RAM.)

3 Metres of flux-cored 60/40 tin-lead solder

Good quality, 0.7mm diameter - ideal for fine electronics work.

Lower RAM replacement module for ZX Spectrum

A PCB module for replacing all eight of the Spectrum's 4116 lower RAM chips with its onboard low power SRAM IC.
A slightly updated design (May 2025) - now uses round pins that fit into Turned Pin type sockets. This allows the module to be removed (and replaced with traditional chips again, should that ever be desired). It can of course be soldered directly to the PCB instead.
Note: Not suitable for pressing into standard stamped pin type sockets as the module's round pins do not align well with these types of sockets.
A kit with the lower RAM module and suitable sockets is listed below if required.

Spectrum Lower RAM replacement module with sockets

Lower RAM replacement module for ZX Spectrum with sockets

As described above but also includes 8 Turned Pin Sockets allowing non-permanent fitting.

Upper RAM replacement module for ZX Spectrum

A PCB module which replaces all eight 4532 ICs used for the upper 32KB of RAM in the Spectrum with its onboard low power SRAM.
This is a slightly updated design (May 2025) which has round pins that fit best into Turned Pin type sockets (a kit which includes the sockets is available below). This means it can be removed / replaced with standard chips again later should that ever be a concern. It can be forced into stamped pin sockets though this may bend its pins slightly. Of course it can be just soldered directly to the PCB if you wish.
Suitable for Spectrum motherboard issues 2-6
Printed instructions are included with the board.

Please note: If you need to upgrade a 16KB machine which has not been upgraded to 48K before you will also need the support logic chips (order 1 x 74HCT00 for IC24, 1 x 74HCT32 for IC23 and 2 x 74HCT157 for ICs25+26 - these are listed above.)

Switch Mode 5v Regulator - Modded for horizontal mount (replaces 7805)

MuRata / OKI Switch Mode 5v Regulator (replaces 7805)

A direct replacement for the cheap but inefficient 7805 found in the Spectrum. A high-efficiency switch mode regulator so wastes very little power as heat (the Spectrum's heatsink is completely removed when this device is fitted!)

Made by Murata / OKI these deliver 5 volts at up to 1.5 Amps (unlike unbranded types which are limited to 1 Amp)
Short circuit, Over current and over temperature shutdown
Modified by myself for horizontal mounting - essential for Issue 2 boards in rubber key cases due to space constraints (Optional on other Spectrum 48 boards. See 128 mods for the unmodifed vertical mount version.)
Can also be used in the ZX81 (splay out the outer legs slightly when fitting).