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Various ICs as used in the Sinclair ZX Spectrum. All chips are new, unused unless stated.
Click on the product thumbnail for an enlarged view.
4116 Spectrum "Lower RAM" Chip
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
74LS04 Logic Inverter IC
As used in Issue 6A Spectrum motherboards and also on some models of Spectrum 128
74LS157 IC (Texas Instruments)
7805 Voltage Regulator
Replacement 5 volt regulator IC for the Spectrum, (breadbin) Commodore 64, ZX81 etc
Diagnostic Test ROM for Spectrum 16/48
Nebula - A Spectrum 16/48 ULA Replacement Module
Availability update 5-5-2021: Unfortuantely the current global chip shortage means the supply of Nebulas will be very constrained. I have a few parts left so can at least build some boards in the coming weeks.
RAM Upgrade Kit for 16K ZX Spectrum (to 48K)
.. brand new support logic chips for the upper RAM:
.. 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 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.
ROM Replacement (EPROM) Kit for the Spectrum 16/48
It is possible to replace the Spectrum's ROM with an EPROM should it become faulty. However, a small modification must be made to the Spectrum PCB. This kit contains the necessary components:
One advantage of replacing the Spectrum ROM with a 32KB EPROM is that it allows two different ROM images to installed if desired (the ROM selection is based on the connections to the PCB - it's also possible to use a SPDT switch for selection, EG: See this video.) EG: Having a diagnostics ROM in the second ROM slot can be very useful. (Please see the Spectrum 128 section for ROM replacements for that machine - no extra components/mods are required there.)
VERY IMPORTANT: You must email the ROM file(s) you wish installed on the EPROM and I'll burn them before dispatch- contact me for details. Note that the EPROMs I supply are write-once devices so cannot be reprogrammed once the ROM image has been burned. (If desired, the EPROM can be supplied blank for burning with a EPROM burner - just let me know in the Special Instructions box at checkout).
Switchable ROM Replacement Board (No PCB mods required)
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.
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.
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 74HC157 in addition to this board)
Z80 CPU - New