Spectrum Modifications

Items for modifying Spectrum PCBs..

Products:

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100uf Capacitor for Spectrum video mod

A 100uf  Capacitor

A capacitor suitable for making the composite video mod on ZX Spectrums

Please see this article for details.

Price: £ 0.25   Add to cart. (12 in stock)
A Set Of Replacement Capacitors For Spectrum 16/48 and Composite Mod Kit

Axial Electrolytic Capacitors For ZX Spectrum / Composite Video Mod Kit

A set of replacement electrolytic capacitors for the Spectrum 16 / 48 / 48+ (motherboard versions from 2 to 6A) and components for applying the optional composite video modification.

For ease of fitting, these capacitors are axial types (ie: they have a lead coming from each end) - the same format as those originally fitted to the PCB.

  • 3 x 1uf 63v Axial
  • 1 x 4.7uf 63v Axial
  • 7 x 22uf 25v Axial
  • 2 x 100uf 25v Axial
  • 1 x 4.7uf Radial - for issue 2 boards that have had Sinclair's modification near C34 during a past service. 

The exact number of capacitors required varies across the PCB revisions but there will be enough here for all types. Printed fitting notes are included.

The kit also includes the following components which can be used to modify the Spectrum's video output to give a composite video signal for a much improved picture:

  • A 100uf radial capacitor (Passive style Composite video mod*)
  • A BC549C Transistor (Active buffer style Composite video mod*)

* Both video mods give a composite signal from the standard Spectrum video connector, which is much improved over RF (with care, the mod can be easily reversed). The transistor version produces a brighter picture and buffers the output from the Spectrum video circuit, however, it may not work on all TVs. The passive (capacitor) mod is simpler and should work with all TVs but the picture is generally not as bright. Fitting instructions for both are included.

Price: £ 2.99   Add to cart. (7 in stock)
BC549C Transistor

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.

Please see this article for details.

Price: £ 0.25   Add to cart. (14 in stock)
De-solder Braid / Wick 0.5 Metres

De-solder Braid / Wick (0.5 Metres)

  • Ideal for assisting repair work on motherboards etc
  • Sold loose 0.5 Metres - ample for small jobs like for re-cap, chip replacement etc
  • High quality Soldamop braid with excellent solder draw.
Price: £ 0.99   Add to cart. (7 in stock)
Heatsink adhesive 6g Tube

Small Tube Of Thermally Conductive Adhesive

  • For attaching heatsinks to chips
  • 5 gram tube - more than enough for several chips
  • Instructions supplied
Price: £ 1.50   Add to cart. (9 in stock)
Heatsink for DIL Chips (40 Pin)

Heatsink for 40 Pin DIL ICs

Heatsink suitable for 40 PIN Chips such as the CPU in the Commodore 64 and ULA in Spectrum Plus. (Note: There is not enough room for it in the rubber-keyed Spectrum unless you desolder the ULA's IC socket and fit the ULA directly onto the motherboard.) Can also be used on the shorter SID and PLA chips if you dont mind the heatsink overhanging (it could be cut down of course). 

Dimensions: 51mm x 19mm x 4.8mm

Attachment methods: The heatsink is not self-adhesive - it requires either a thermal adhesive pad or thermally conductive glue which I sell separately - please see my listings nearby.

Price: £ 1.50   Add to cart. (15 in stock)
Internal reset switch for Spectrum+

An original internal reset switch for Spectrum+ (used)

  • As used in the Spectrum+ (soldered across capacitor C27 - or at the provided pads on issue 6 motherboards)
  • Tested, working.
Price: £ 2.49   Add to cart. (4 in stock)
RAM upgrade kit for 16KB Spectrum (to 48K)

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

Comprises:

  • 8 x 4164 150ns Upper RAM chips (Unused, old stock ICs  - brand may vary, all tested before dispatch.)

.. 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.

Price: £ 9.99   Add to cart. (2 in stock)
RAM upgrade kit for 16KB Spectrum (to 48K) PCB version

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

This version of the Spectrum RAM upgrade kit offers a cheaper, modern alternative to using individual DRAM chips. A small custom daughterboard PCB 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.


Price: £ 9.50   Add to cart. (2 in stock)
Replacement electrolytic capacitors for Sinclair ZX Spectrum 48K (radial types)

Radial electrolytic capacitors  for Spectrum 48 / Composite mod kit

Good brand (Panasonic etc), long life capacitors suitable for re-capping a ZX Spectrum 48K.

These are radial type capacitors (which have both leads coming from the same end) so one wire has to be bent over the body of the capacitor when fitting - see this photo for example. Please see my other Spectrum capacitor set for axial types.

The pack comprises:

  • 3 x 1uf 50v
  • 1 x 4.7uf 50v
  • 7 x 22uf 25v
  • 2 x 100uf 25v

And also includes the following components for applying the composite video modification if desired.

  • 1 x 100uf capacitor
  • 1 x BC549C transistor

Printed instructions are included.

Price: £ 1.99   Add to cart. (2 in stock)
Solder 3 Metres 0.7mm

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

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

Price: £ 0.99   Add to cart. (4 in stock)
Spectrum Lower RAM replacement board

Lower RAM replacement board 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.

  • Suitable for Spectrum motherboard issues 2-6
  • Uses a modern low power SRAM
  • Can be pressed into DIL sockets or soldered onto Spectrum PCB when the 4116s have been removed.
  • Click here for fitting instructions - printed version also included with board.
Price: £ 9.99   Add to cart. (1 in stock)
Spectrum Upper RAM replacement board only

Upper RAM replacement board 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.

 

Price: £ 8.75   Add to cart. (1 in stock)
Switch Mode 5v Regulator (replaces 7805)

MuRata 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!)

  • High efficiency 5v 1.5A output
  • Short circuit protection
  • Over current shutdown
  • Over temperature shutdown
  • Modified by myself for horizontal mounting in Spectrums (Issue2 - 6 motherboards).
Price: £ 4.99   Add to cart. (5 in stock)
Thermal Adhesive Pad for 40 DIL Heatsink

3M Brand Thermal Adhesive Pad for 40 DIL chips / heatsink

Thermally conductive double-sided adhesive pad for attaching 40 pin DIL chip heatsink.

3M Product code: 8940

Dimensions (appox) 50mm x 19mm x 0.19mm

Price: £ 0.90   Add to cart. (9 in stock)