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One new Superfo Harlequin Issue 4B motherboard PCB, professionally manufactured to Don's design and specifications and ready for assembly. Finished in ENIG (Electroless Nickel Immersion Gold), to provide excellent oxidation resistance and soldering characteristics - the PCB is designed to fit an original ZX Spectrum case, including the early rubber-key models and later "+" (pre-Amstrad) models. (See Note 4 below.) The pack also contains the obsolete or difficult-to-source parts that generally cannot simply be ordered new from distributors such as CPC, Farnell, DigiKey or Mouser. These are: One Z80 CPU. Zilog ceased production of the original Z80 in 2024, so these devices are necessarily NOS or refurbished. Every CPU supplied is individually tested in a working Harlequin Issue 4B before dispatch. One SIL-packaged, 6-pin common-anode signal diode network, as required for the DN1 position on the PCB. Don's original build instructions show how to make the network by joining five individual 1N4148 diodes, as a suitable packaged replacement is now difficult to obtain. The device supplied here is NOS (New Old Stock), tested and proven to work in the Harlequin. One new HTC Korea 74HC04N hex inverter IC, intended for U13 on the PCB. Although 74HC04 devices are nominally interchangeable as digital logic, U13 forms part of the Harlequin’s crystal oscillator circuit, where behaviour can vary between manufacturers. Some batches of the Texas Instruments SN74HC04N specified in the original BOM have proved unreliable in this circuit, producing an incorrect CPU clock. The HTC 74HC04N supplied with this pack has been tested in a Harlequin Issue 4B and confirmed to produce the correct 3.54 MHz clock. One UM61512AK-15 SRAM IC, intended for U3 on the PCB. This device is used as the upper RAM in the Harlequin design and is no longer manufactured, so supplied parts will be NOS or refurbished. Every device is tested in real Harlequin hardware before dispatch. One sound generator IC intended for U54 on the PCB. The supplied device will be either a General Instruments AY-3-8910 or Yamaha YM2149F. Both are compatible with the Harlequin design. Neither device has been manufactured for many years, so the part supplied will be NOS or refurbished and, crucially, individually tested in real hardware. No TL866II or T48 EPROM programmer? No problem. This pack includes one new SST39SF040 512KB flash ROM IC intended for U2 on the PCB, pre-programmed with the Superfo 128 ROM image provided by Don Superfo and ready to install. No programmer is required.
THIS IS NOT A COMPLETE COMPONENT KIT. Only the PCB and parts specifically listed above are included. You will need to source the remaining components required for the build separately. The complete BOM and build information can be found on Don Superfo's GitHub page for the Issue 4B. (Suggested search: “GitHub Superfo Harlequin 128”.) Handily, Don includes suggested Digikey part numbers for the parts, making the ordering process straightforward. The PCB and currently manufactured components are new. Obsolete ICs may be NOS (New Old Stock) or professionally refurbished. Regardless of whether they're new, NOS or refurbished - every supplied component is tested in a working Harlequin issue 4B test system, and each complete set is verified together to ensure functionality and compatibility before dispatch. The supplied flash device contains original Sinclair/Amstrad ROM software, enhanced ZX Spectrum ROM software and diagnostic ROM software. All software remains copyright of its respective copyright holders, and the copyright notices contained within the ROM images have not been altered. The Harlequin Issue 4B PCB fits an original ZX Spectrum case as described above. If you choose to install the optional reset switch, joystick port or RS232 hardware, case modification may be required. There's an active Facebook group (owned & run by Don, but I'm also a member) where you can get further information and build resources - called "Superfo Harlequin 128" - do join if you'd like to ask questions. If you choose to purchase this pack, I'll reach out with the following to assist you with your build: Correct orientation of the DN1 part is important during assembly. Accordingly I'll reach out with directions on where to find a short instructional video for this part. Secondly, I've constructed an interactive BOM web page from Don's layout PDF which is very useful for finding the many locations on the board in which you have to fit components - I'll also let you know where to find that. It's a huge time saver, and stops you searching for ages trying to find obscure locations.  |
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