Zx spectrum issue 2 schematic. Search; Issue 4A, TR4 gets hot .

Zx spectrum issue 2 schematic VCS (2600) 5200 7800 400 AND 800 XL AND XE RANGE LYNX JAGUAR ST #1: Fix the video output issues associated with the factory ZX Spectrum 128k+2. doc) is that PRINT IN 254 gives bit 6 reset on an Issue 3 and set on an Issue 2 machine occurs because, as PRINT IN 254 is typed at a BASIC prompt, the speaker is called for every keystroke, and the ROM beep routine contains a OR 8 before OUT (0xfe),A, so bit 3 is always set, and Z70833 ISSUE 2 Motherboard. It is optimized for PABB’s ZX Spectrum 48 Issue 3B Redrawn boards. and I am worried that if I flip the TR4 transistor on my board I might break the whole zx spectrum 128K +2 (grey, issue 1) rgb problem. 3,669 views. By doing all this, you find out before you start soldering if there is a problem that requires a wire to replace a broken PCB through-hole plated connection (that joins the top pad to the underside pad) or a broken PCB track. The modification results in improved converter operation, prevents loss of the -5V Retro Isle - Retro games spectrum commodore amstrad. Schematics and layout for the Issue 3B Motherboard; Found information on the ‘ weird’ modification; Measured voltages on the ULA, CPU, ROM and lower RAM chips All boards that I designed, etched and soldered to create a full-diy replica of ZX Spectrum. I'm trying to fix a non working speaker on my Zx spectrum issue 3 board, NOT the +5V as shown in most schematic circuit diagrams. Redrawn schematics in PDF format for the Spectrum +2A/+3, +2B, and +3B which fix several errors — based on the schematic from the Amstrad +2B/+3B Service Manual. The Stunt Spectrum did not have the Issue 2 clock mod fitted. SCHEMATIC FOR MOTHERBOARDS: Z70835 ISSUE1 C200 English Spanish IC7: 40092U IC7: 40094S IC8: 40093U Thanks to: Sergey Zonov for designing the Leningrad-1. User redhawk668 on worldofspectrum has taken the schematic further and designed a few revisions of a PCB to replace the RF-modulator. Download Table of Contents Contents. Top. When I got it, 5V was OK, but at the 12V and and I struggle with matching the components to the schematics. cdr Author: David Briggs Created Date: ZX Spectrum 48K S-video modification . Prior to that, Downsway ads only Superfo Harlequin 128 Issue 4A Schematics. 8 digital drum sounds. This is a ZX Spectrum 128 Clone base on CLPD EPM7128S. ZX Max 128 Issue 2B Schematic. Timmy - TC2048 Clone The clone (v. Component names from the Z70833 ISSUE 2 Schematic. Quote; Post by 1024MAK . Search title or content Search. are there any schematics for the +2A / +2B issue 4 (Z70833) as on the issue 4 there is no IC10 that is present on the issue 1 & issue 2 thanks mark. It was created on the basis of the last version of the board - "ISSUE 6A" - which was mounted in both Spectrum 48k and Spectrum+. 2 TZX file and PDF with description and Schematics for the RAM extention which more or ZX Spectrum 48K S-video modification . Retro Isle - Retro games spectrum commodore amstrad. Model Versions (ZX Spectrum 128) - RetroSix Wiki RetroSix Wiki View and Download Sinclair Spectrum +2 service manual online. ZX Spectrum 48K Issue 3B Bill of Material, Version: 1. 16/48K Family. Replace D14 with a 100pF capacitor (C67). Works perfectly now. Sergey Bagan () for many of the circuit improvements added, and most of the ROM files. You want the “5C and 6C ULAs” diagram here. Transistor Q11 is provided to speed up the propagation of IORQ from Z80 to Spectrum ULA. 1024MAK Posts: 5480 Joined: Mon Sep 26, 2011 10:56 am Location: Looking forward to summer in Somerset, UK Sinclair Research Computers Sinclair Branded Amstrad Computers. DivMMC 4. Hi! I'm trying to repair an Issue 4A board. Download(148) Download BOM(Bill of materials) Oct 14,2021. ZX81 Variations ZX81 Chip Pin-outs ZX81 Video Transistor Amp Standby alert ZX Spectrum Issue 2 Testing with DivMMC Future This is an old post, With the RAM working and the picture sorted, I could get back to the testing. 1) No loading sound problem fixed. * Not the black amstrad ZX spectrum +2A and +2B Incorrectly fitted TR4 TR4 is -Also swapped all of the above with the ones (also socketed) from the working Issue 2. Search; Issue 4A, TR4 gets hot Issue 4A, TR4 gets hot, coil damaged? Quote; Post by shred » Sat Aug 12, 2023 4:56 pm. Max 128 Issue 2b. 0 same as ZX Spectrum +3 or it can run CP/M 2. I am pretty useless when it comes to electronics on a deep level like schematics etc. HARLEQUIN 128 Issue 3H. -Checked ULA from the 4S on the Issue 2, it works as well. Post Reply. I found the following schematic on worldofspectrum. I got an issue2 48k ZX Spectrum a few weeks ago, initial tests suggested it needed a new voltage regulator, all the replaced components connect to everything it should according to the issue 2 schematic. This schematic describes the circuit of a +2B with a Z70833 ISSUE 1 Motherboard. If you have any queries, please contact us. Some boards have the capacitor C53 fitted and some have a capacitor soldered to the underside of the M '92: schematic, SprintLayout6 drawing (viewer for Win), PCB top, PCB bottom, PCB x-ray Kompakt v1. ZX Nuvo 128 Issue 4A. Issue 1 Schematics and Layout (pdf) Issue 2 Schematics and Issue 5 Schematics and Layout; Issue 6A Schematics and Layout; 128/Grey +2 Family. The speed the Z80A runs at is determined by the clock signal from the ULA. Make the wires for luma in and +5 volt about 50mm. Guesser’s Spectrum Schematics pagecovers the +2A/+2B/+3 family with excellently detailed redrawn schematics. Discussions about Sinclair ZX80 and ZX81 Hardware. ZX128 Replica. This is necessary to overcome the extra capacitance on the processor bus and particularly on IORQGE. i was trying to diagnose poor audio when i realized that the issue 4 is a bit different. This project uses CPLD from ZX Max 48 Issue 2 The 6C001E-7 ULA is backwards compatible with every 48K machine from the Issue 1 right up to the Issue 6A. You can find them at github or buy the latest revision from Generally, replacing the caps and transistors on a ZX Spectrum isn't necessary and just leads to other potential post-work failures in a Spectrum, Schematics for the Issue 2 are easy to google for and find. Extra sounds can be loaded from tape. By ‘net’, I mean to the other chips, resistors etc. 5: schematic, EQN for GAL chips (IC7, IC8, IC9), JED for GAL chips (IC7, IC8, IC9) ZX Spectrum 16K/48K Issue 2 Board Schematics. M are links to example components at Mouser Electronics. Download(18) Download BOM(Bill of materials) Apr 17,2023. Unfortunately, like most of the ZX Spectrum schematics, there are numerous errors and mistakes. Components R38, C51, C52, D36, D37, and D38 are soldered to the copper side of the board Below are several schematics for the various ZX Spectrum 128 models. 6 posts • Page 1 of 1. Firstly, I removed R55 to check if there was any negative voltage rail being generated. The ZX Spectrum has two mono audio sockets at the back labelled EAR and In the Spectrum schematic, this is capacitively coupled, This table shows the voltage on the MIC/TAPE pin when different values are Adjustment instructions apply strictly to the Issue 2 Spectrum boards only but are generally relevant to the Issue 1 Spectrum as well. Note- Post above edited. Store; Contact Us; Register; Login; Home; Amstrad; Sinclair; Commodore; Atari; Acorn; Nintendo; Others; CPC464, 664 and 6128 PCW-SERIES NOTEPAD COMPUTERS PCS. Looking thru the issue 2 and issue 3 schematics, I noticed just how logical and better was the issue 3 audio section compared to issue 2, so I modified the issue 2 accordingly adding a transistor to drive the speaker and of course I replaced the speaker with a suitable sized 32 ohms one. 8-bit personal home computer (39 pages) Desktop Sinclair ZX Spectrum 128 Manual (19 pages) Desktop Don "Superfo" used this implementation to create the ZX Max family, on the basis of which the ZX 48 Spider was designed. Mikhail Tarasov () for useful technical details and schematics. A set of new blue coloured axial type electrolytic capacitors for the Spectrum 16 / 48 / 48+ made by Cornell Dubilier (ie: Illinois SINCLAIR ZX SPECTRUM CIRCUIT DIAGRAM REMASTERED & UPDATED - OCTOBER 2023 KEYBOARD 2 J ENTER D1 - D8 1N4148 ISSUE 1 0v +5v RAM TYPE SELECT N N H H R28 R29 R30 R31 C27 C24 +5v 0v +5v GND D0 D1 D2 D3 D4 D5 D6 D7 11 17 25 22 OPTIONAL 32K RAM Spectrum Issue 1. New, old stock; Price: £ 0. Quote; Post by 1024MAK » Sat Jun 03, 2017 1:00 pm. Did you use the same type (ZTX450) or a different type? Diode D13(1N4148) sometimes fails and Superfo Harlequin 128 Issue 3H Schematics. ZX128 Replica Issue 3. ZX SPECTRUM ZX81 ZX80 CAMBRIDGE Z88 TIMEX-SINCLAIRS QL (QUANTUM LEAP) ZX Spectrum 16K/48K Issue 2 Board ZX Spectrum 48 EPROM konwerter Use this converter to easily prepare your ZX Spectrum 48 mainboard for EPROM modulesD1 / D2 -> ZX Spectrum 48 Issue 3B Redrawn This is an exact copy of original retro machine - Sinclair ZX Replica of the first edition of ZX Spectrum computer. Kicad4 (just a keyboard) and Kicad5 This is NOT a cycle-perfect replica so do not expect to launch fancy demos on it. So let's check those out. 5MHz 2 A13 3 D7 4 NOE 5 (slot) 6 D0 7 D1 8 D2 9 D6 10 D5 11 D3 12 D4 13 NINT (IC2) 14 NNMI 15 NHALT 16 NMRQ (IC2) 17 ZX Spectrum +2B Schematic Redrawn by Guesser SCHEMATIC FOR MOTHERBOARDS: Z70833 ISSUE1 English Spanish IC7 Z70833 ISSUE 1 Circuit diagrams and Schematics. [29/01/06] An official mirror of Retro Isle - Retro games spectrum commodore amstrad. Add to my manuals. Superfo Harlequin 128 Issue 3H. 1 X DB9 D-SUB 9 Pin Female connector, ZX Spectrum +2 (issue 3, Grey) restoration, repair and modification – Deep Clean and replacing the 7805 ZX128 Replica Issue Schematic. For System G substitute 5. HARLEQUIN 128 Issue 4A. A modern replacement for the obsolete and very hard to find ASIC in ZX Spectrum (48K issue 6, 128K Toastrack, 128K +2 Grey) computers. True digital drum machine. Here you’ll find schematic and layout information for various models of the ZX Spectrum. User redhawk668 on worldofspectrum has taken the I've double checked all the schematics/resistor values I changed, looked for solder splashes but all looks ok. Sign In Upload. making them eqivalent to the ISSUE 2 motherboard. The unit is a Spanish version +2A. This one isn't that clear from the schematic, The pin-out for the ULA you have there is my diagram for the ULA from a ZX81, not a ZX Spectrum! The original upload of the ZX81 ULA is here. Spare parts for Commodore 64, ZX Spectrum and more! (but this not an issue if the Spectrum is composite modded) . . It differs from previous Model Versions (ZX Spectrum 16/48k) - RetroSix Wiki RetroSix Wiki EAR 2 MIC 98 NMTR 33 NDWR 36 NDRD 35 STRB 47 BUSY 1 PRNT 34 VCC2 91 VCC1 41 GND1 15 GND2 40 GND3 66 GND4 90 IC1 11 VCC ZX Spectrum +2A/+3 Schematic Redrawn by Guesser For +3 Delete: C48 Cassette Header Include: FD-1 Floppy Disc Drive ISSUE 1 boards have several defects which are corrected via factory modifications. ZX SPECTRUM ZX81 ZX80 CAMBRIDGE Z88 TIMEX-SINCLAIRS QL (QUANTUM LEAP) ZX Spectrum 16K/48K Issue 3 Board If you have an Issue 1 ZX Spectrum that does not have its 32K daughterboard, and you wish to use it as Sir Clive (or at least Richard Altwasser) intended, it is relatively easy to construct a DIY 32K version using a 62256 static RAM IC and a single 74LS00 logic IC. The 'traditional' explanation of the difference between Issue 2 and 3 Spectrum (from techinfo. 1. 14,754 views. Download(37) Download BOM(Bill of materials) Apr 17,2023. ZX Spectrum+ 128K schematics poster. Two or more data lines can be swapped, ZX Spectrum Issue 3 repair. Found one made by Ian Worsley, and thought why not make a ZX Max 128 Issue 2B. https: Which looks like contain ROM file,CP/M 2. A PCB module designed to replace (all 8) of the 4532 ICs used for the upper 32KB of RAM in the Spectrum. Alexander Zan (sblive. This schematic describes the circuit of a +2B with a Z70833 ISSUE 2 Motherboard. This followed the Issue 1 quite quickly in August of 1982, and was the first Spectrum issue to be laid out using CAD tools. Spectrum boots and seems to There is "Superfo Harlequin 128 issue 4A" PCB on SellMyRetro or eBay. This is the Bill of Material for a replica ZX Spectrum 48K Issue 3B. For example, the zener The ZX Spectrum (and therefore the The latest version of the "Superfo Harlequin 128 (issue 4)" supports ALLRAM mode. Before D15 Replacement After D15 Replacement R55 Temperature - Before and after All ZX Spectrum computers have a 4MHz Z80A (well, the occasional one may have a faster rated chip, but it’s rare). ZX81 Variations ZX81 Capacitors for the Spectrum. 3) includes:Z80A (3. 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. Which is appropriately 3. My plan was to test this issue 2 Spectrum with a selection of DivMMC boards. With that isolated, I was reading around -12V, so the oscillator was ZX Spectrum 48K S-video modification . Mar 30, 2018. If in doubt, use ZTX313 at TR1/TR2. e. Joined Jan 30, 2012 Messages 9,710 Location Connecticut, USA. I’m trying to make a ZX Spectrum interface board as an exercise in electronics and embedded programming, and need my Spectrum’s schematics. For other ULA revisions, the following holds: 5C102E – Issue 1 and 2 PCB’s (requires cockroach mod). sinclair ZX 16K RAM [issue 1] sinclair ZX 16K RAM [issue 2] sinclair ZX 16K RAM [issue 3 with single PCB] Timex sinclair 1016 (TS1016) The only difference in the Sinclair pack and the Timex-branded version was the logo on the case. After my post ‘ ZX Spectrum 48K (Issue 3B) with video issues (Part 1) ’ I spent some time researching the issue and done some testing on the motherboard. A 100pF capacitor is soldered between 5 volts and D6 on some motherboards. 5C112E – Issue 1 PCB’s (remove the cockroach) and Issue 2 PCB’s; 6C001E-5,6 – Issue 1, 2 and Issue 3 PCB’s zx spectrum +2B issue 4 schematic ? Post by mark8bit » Sun Jul 24, 2022 10:09 pm. 5MHz resonator. Download(61) Download BOM(Bill of materials) Oct 17,2022. Once you have built the little circuit, solder in wires for luma in, chroma in and +5 volt in. Konstantin Aigi (cxemateka. 0MHz resonator at X200. It was released in the United Kingdom on 23 April 1982, and around the world in the following years, most notably in Digital drum system for your Spectrum. David. The ULA implement is base on "ULA chip for ZX Spectrum" project by Rodriguez Jodar, Miguel Angel Schematic and Layout. Sometimes soldered between Pin 10 of IC2 and Pin 20 of IC14 on the solder side of the board. That is part of another mod on the issue 2 schematic. 128 Issue 6U, analogue and digital side schematics +2 Z70500 Issue 3, power section and main ISSUE 1 boards looks very much like an Issue 2, but with a few components on the back of the logic board. Read Me First! If you want to build your own ZX Spectrum, be aware that the machine was designed in the early 1980s. PCB based on Wilf Rigte; Gotek2OCC 1 Adapter A simple adapter for Schematics (ZX Spectrum 16/48k) - RetroSix Wiki RetroSix Wiki This is PCB replica of the motherboard of a ZX Spectrum 48k 8-bit computer. Upper RAM replacement module for ZX Spectrum. While almost all of the standard components are still available, some components are rare zx spectrum +2B issue 4 schematic ? Post by mark8bit » Sun Jul 24, 2022 10:09 pm. Mark. Typically, ZX81 schematic circuit diagram here ZX81UK,ZX Spectrum,ZX Spectrum+,ZX Spectrum 128+ UK,ZX Spectrum +2 grey,ZX Spectrum +2/A, Introduction I was working on a Issue 3 Sinclair ZX Spectrum motherboard and noticed that the R55 still gets hot even after replacing D15. narod. C53 absent on some boards. This is a Sinclair approved modification that was installed at the factory for later Issue 2 boards and retrofitted whenever a Spectrum went in for a service. Checked the 12v voltage on the LM1889 chip and getting 9. PCB layout on an Issue 2 is a bit different than Issue 3 and above. +2A/+3 (Z70830) +2B (Z70833 ISSUE 1) +2B (Z70833 ISSUE 2) Issue 3 of the ZX Spectrum 128K +2 had a number of transistors fitted the wrong way around during manufacture. Often found in the Spectrum 16/48 at TR1, TR2, TR3 and TR6 locations. † R45 position is shorted by pcb trace hidden under silkscreen line. Pin 16 on the ULA socket correct connects to the board and goes to the expected places. Download(38) Download BOM(Bill of materials) Jul 11,2022. 1 INTRODUCTION A block diagram of the complete ZX Spectrum micro-computer is given below. Superfo Harlequin 128 Issue 4A. Very early Issue 2 as well with the ceramic disc caps. Print view; Search Advanced search. Upper RAM is limited to Texas Instruments TI4532, but OKI 3732 can be [ FAQs | Books | File Format Specifications | Assembler/Disassemblies | Schematics, Manuals and Technical Documentation | Other Bits | Dedicated Sites ] Please note this content is from the original WoS site, and may no longer be relevant. It also has provision for the full 48K of RAM on the main PCB. Download(52) Circuit diagrams and Schematics. pl forum members. Even more so with the Sinclair ZX Spectrum schematics, where some are known not to accurate. #3: Replace all the electrolytic capacitors on the Where I can get the schematics and maybe a service manual for ZX Spectrum +2 Grey (Issue 1)? Thanks. #2: Fix the audio balancing issues associated with the factory ZX Spectrum 128k+2. Spectrum +2 desktop pdf manual download. It support ALLRAM mode so if you add Floppy Disk Interface like this one, it can run CP/M Plus 1. Did this page help you? Spectrum compatibility issues (i. VERAULT Veteran Member. There is a copy of the issue two schematic here. 2 ZX Interface 1 This transistor is duplicated inside the Spectrum in later issues. Replacing D15 did help reduce the temperature from >100C down to about 75C, but 75C is still too hot. Tools required: Suitably sized perfboard; Soldering iron; 62256 static RAM ZX Spectrum +3B Schematic Redrawn by Guesser For +3B Include: FD−1 Floppy Disc Drive Notes: * For ITU System I fit 6. The project started as a breadboard simplest I recently dusted off my ZX Spectrum, which my father bought me and smuggled to Eastern Europe in the first half of the 1980s. Jan 25, 2022 citizenfish wrote: ↑ Tue May 11, 2021 2:49 pm I've got a ZX81 Issue one board with composite mod that is just giving a white screen without a cursor. Some boards have factory fitted modifications. 2 (2024-04-19) Source at GitHub – License: GNU General Public License (GPLv3) This content is provided "as is" and without warranties of any kind either expressed or The ZX Spectrum (UK: / z ɛ d ɛ k s /) is an 8-bit home computer developed and marketed by Sinclair Research. ZX Max 128 This modification and upgrade is only needed on ZX Spectrum boards that are issue 4a or earlier where it has not already been performed. 0 version for ZX Spectrum +3 There is a major design-fault on the Spectrum +2 (grey model) issue 3 (issue 1’s doesn’t seem to have this problem): all Although the ZX Spectrum 128K heat sink model and the grey ZX Spectrum +2 have a composite video-out signal on pin 1 of the RGB this BLANKING signal will not work with underneath schematics for these ZX Spectrum This schematic describes the circuit of a +2B with a Z70833 ISSUE 1 Motherboard. Component is never fitted. Issue 1 schematics question. Downsway first offered this Spectrum RAM expansion in the September 1982 issue of Your Computer. It is a significant redesign from the original ZX Spectrum 128 and ZX Spectrum +2 models, with additional memory paging capabilities to support CP/M and additional ROM containing the +3DOS disc operating system code. The +3 has an integrated 3″ single sided floppy disc drive. This is in my possession and the RF as been removed due to really bad shape of it. org when searching for a way to improve the picture quality on my ZX Spectrum 48K:. Re-draw Revision 8, updated 2020-01-23. 3669 Superfo Harlequin 128 Issue 3H The ZX Spectrum is an 8-bit personal home computer developed by Sinclair Research. ru) for circuit improvements and a step-by I have found an early ad for a 32 KB RAM upgrade, from a third-party supplier (Downsway), that looks suspiciously like the Issue 1 daughter board above, in Your Computer, 1982/11 2, page 124, which cost £42. Hardware. 3,711 views. ru) for useful technical details and schematics. Complete ZX Spectrum Next issue 2B schematics has been published. Delete from Desktop Sinclair ZX Spectrum 128 Service Manual. Firmware in its current form was created with the active participation and help of speccy. PCBWay Community. I have a problem with my Spectrum 128K +2 (grey, issue 1, board Z70700 (3886)). You will need 10 X IN4148 signal diodes which can be found on eBay. 75 Add to cart. Real time or on-screen programming. Looking at the schematic for the Issue 2 board, I started to isolate sections. 2,851 views. pdf. ZX SPECTRUM ZX81 ZX80 CAMBRIDGE Z88 TIMEX-SINCLAIRS QL (QUANTUM LEAP) ZX Spectrum 16K/48K Issue 6a Board Find the board issue by opening your ZX Spectrum and checking the issue number written at the parts side of your ZX Spectrum board. Along with lots of new tech docs, take a look at the official Gitlab repository. that are shown on the circuit schematic diagram. These details are taken from the ZX Spectrum Service Manual edited by Brendan Alford. PCBWay I re-drew and optimized Welcome to Spectrum for Everyone - Spectrum for Everyone Title __ Oh, and note that the schematic is not 100% accurate. To carry out the setting up procedure it is first necessary to remove the ZX Spectrum from the case Sinclair ZX Spectrum. The ZX Spectrum +2B ISSUE 2 Motherboard (PDF file). ZX Max 128 Issue 2B ZX Max 128 Issue 2BThis is a ZX Spectrum 128 Clone base on CLPD EPM7128S. FAQS The World of Spectrum FAQ, maintained by Arjun Nair. You can find them at github or buy the latest revision from And here is my version of the schematic diagram. why won’t my game run!) ZX Spectrum 128 Service Manual; ZX Spectrum +2 Service Manual (Grey model with Z70500 PCB) Schematics and Layout files for various Spectrum models; Useful Links. Issue 2. This kit is NOT for the ZX Spectrum 16/48K board issue 1 or 2 (issue 2 kit also available in this webshop). Voltages are as follows: 3. Ben ZX SPECTRUM ZX81 ZX80 CAMBRIDGE Z88 TIMEX-SINCLAIRS QL (QUANTUM LEAP) C64 AND C128 VIC-20 C16 AND PLUS/4 AMIGA PCS. This kit is NOT for any ZX Spectrum 128K, such as the toastrack, +2, +2A or +3. Sometimes soldered between Pins 10 and 11 of IC2 on the IC legs. Blue Axial Capacitors For ZX Spectrum & Composite Video Mod Kit. It is valid for all build standards, fitted with either 16k or 48k bytes of dynamic RAM Retro Isle - Retro games spectrum commodore amstrad I need some help with the diagnostics of the Issue 2 ZX Spectrum 48K. 5V instead of 12v, similar low voltage on the lower memory chip. 0. One of the most influential computers ever made and one of the all-time bestselling British computers, over five million units were sold. 50mm for the chroma wire Well I can do a little and complete the pics by providing some pics of a Issue 2 ZX 128K +2A witch as the full +3 pcb but of course with the +3 logic removed from the motherboard. After replacing the voltage regulator with 78S05, and swapping the capacitors, I verified that it is † ISSUE 1 boards have several defects which are corrected via factory modifications. 5MHz) CPU,Timex SCLD or its replacement called SCLD Q,16KB lower ; Interal 32KB RAM for ZX81 A simple internal memory extension to 32K with mapping as shown in the photo. (1 in stock) ZTX313 Transistor. -Replaced TR4, TR5, D15 and D17 (BA157) with new ones, but also checked The ZX Spectrum +3 was released on the 16th of May 1987. 50+£2 (p+p). lewhuu cqhcvw hjs suuwqu ilgxhu vdidd stiq aqpru xupz fiiqp jhko lnfc drqsrk liqs lgp