This method should work the same on all older speccys pre rgb output. The zx spectrum uses like basically any other home computer of the time a linear regulator 7805 and some cs for smoothing the voltage to generate the 5v. Nov 01, 2019 now im back on my retro computers ive put together this quick guide for those looking to diagnose and repair zx spectrum computers. Tynemouth software llp old computers, new computers, bespoke web design and software development, computer repairs, it and media services uk sunday, 19 february 2017 zx spectrum issue 2 repair. This one had issues with video, ram and a broken keyboard membrane. Other rom contents can be loaded into ram, then paged as rom. You see that on commodore pets and c64s with ram faults, but i have never seen it on a spectrum before. Touching ram chips, the screen changes and showed a lot of colour blocks. With a densely populated board such as the zx spectrum, as careful physical examination of the board can sometimes indicate an obvious fault. L break into program zx spectrum screen memory layout. The lil old zx spectrum 48k service manual section 4. There was even a separate numeric keypad released for the spectrum 128, although this is normally only seen in portugal, there. Spectrum next is an expanded and updated version of the zx spectrum, fully compatible software and hardware with the original. The zx spectrum lower ram replacement module is a device that replaces all eight 4116s in a 48k or 16k zx spectrum it cannot be used with any of the 128k models.
Now im back on my retro computers ive put together this quick guide for those looking to diagnose and repair zx spectrum computers. Zx spectrum issue 2 repair and restoration youtube. We have 3 sinclair zx spectrum manuals available for free pdf. The zx spectrum is supplied with either 16k or 48k of onboard ram. If youre just getting started with your spectrum and want to test loading software from a pc or audio player, you might like to try some of the old and new games listed below. Zx spectrum repairs, refurbishments and maintenance wikis. These tests are based on the rom based diagnostics and are intended to assist in diagnosing memory problems that may manifest themselves but where the spectrum itself is partially working for example, minor screen corruption, ability to run 16k games only etc, and. Website providing useful information, including the basic code and table relating to which chip might. These tests are based on the rom based diagnostics and are intended to assist in diagnosing memory problems that may manifest themselves but where the spectrum itself is partially working for example, minor screen corruption. If the computer is a 48k machine the 32k of expansion ram can be isolated. The spectrum psu suffers mainly from the wires in the premoulded plug or lead exit from the box snapping or going intermittent.
Zx spectrum next the official portal for all things next. Apr 23, 2012 i bought a copy of the complete spectrum rom disassembly the spectrums os decoded and annotated, every byte of it, every bug and whistle. For smaller parts ram chips and the like we have no charge, and for the major parts except the ula we charge. Sep 29, 2016 in this retro teardown, we will look at the most iconic computer of british history the zx spectrum. Where a spectrum has initialised correctly but a ram memory fault is. It uses a machine language routine to fill an area of memory either all of upper ram or a portion of lower ram with a sequence of randomly generated values and then. Sinclair spectrum after the success of his two previous computers, the zx80. How to quickly diagnose 48k ram failures, ninja style april 21, 2017 brendan hardware most of you will be used to the distinctive power on screen of the 48k spectrum, where the screen goes black with a white border, and for a fraction of a second vertical red bars can be seen, before the screen clears to the message. Fault diagnosis and repair colour, repair and upgrades 36. Sinclair ql, ql started with white screen normally it was ram fault.
The 512k of ram would have been sinfully luxurious back in the day when the original model came with 16k, although the most iconic spectrums would. Zx spectrum 4 out of memory error repair tynemouth software. Sam coupe compatibile write protection of section a. Ql started with white screen normally it was ram fault. There are more features that you can launch with a keypress directly after powering up this is shown on screen. Lower ram ics on the 48k spectrum are designated ic6 to ic, and represent bits 0 to 7 in that order each memory ic provides a single bit of each byte. On reset, the spectrum should beep once and show a. I bought an interface 1 and zx microdrive each cartridge a squiggly loop of magnetic tape in a small case able to hold a massive 85k or. A diagnostic rom image for the zx spectrum download current version.
For details of the memory upgrade, see later on here. The vla82 is a modern plugin replacement for the spectrum 48k ula type 6c001e7 or earlier. This was arguably the most popular computer in british history and is wellknown worldwide. To find the rams that are at fault we now enter a couple of program lines, no line number required. Mp3 and zipped wav audio files are provided along with a link to more information on the game at the world of spectrum web site. February 6, 2020 phoebus dokos off happening, hero article, news, first zx spectrum next delivered today to one of our ultimate backers. Feb 27, 2020 the 512k of ram would have been sinfully luxurious back in the day when the original model came with 16k, although the most iconic spectrums would be the 48k models.
This module replace the 16kb low memory ram eight 4116 ics of the 16kb or 48kb sinclair zx spectrum. How i did a quick and easy composite mod to my sinclair zx spectrum 48k. It started with a black screen with some vertical lines. You can play any games, demos, use original hardware, you name it. Also covers fixing the video out problem related to the transistor mounted incorrectly at manufacture. I bought a copy of the complete spectrum rom disassembly the spectrums os decoded and annotated, every byte of it, every bug and whistle. Special hardware, such as romantic robots multiface, was able to dump a copy of the zx spectrum ram to disktape at the press of a button, entirely circumventing the copy protection systems. I grew up with 1980s home computers, and have been using, repairing and upgrading them for over 30 years.
In this case, it was an issue 2 board where the colour had drifted, so i wanted to let it run for a while, and run from cold the next day to make sure it hadnt drifted again. How to quickly diagnose 48k ram failures, ninja style. Modifying a spectrum to take a eprom instead of a rom eprom instead of prom in zx spectrum tc2048 how to replace the rom of a zx spectrum with an eprom mark. Over the many years that i have been writing spectrum software a number of habits have formed which may seem odd. If the spectrum is 48k, an upper ram chip ic15ic22 is probably faulty. Zx spectrum screen memory layout zx assembly for the zx. We have all the special parts needed in stock ulas, cpus, ram etc. Sinclair zx spectrum home computer new hardware and repairs. Ideal for installing in an aftermarket spectrum pcb without needing an original ula. The zx spectrum was launched in april 1982, and by todays standards is a primitive machine. If no fault has been found and the computer still has not initialised, the fault could lie in the ram. Kind of sinclair z88 cambridge computer compatibility. We sell a wide range of new and used software and hardware to support the retro sinclair zx spectrum home computer for you to purchase.
Based on the compiler z88dk, the kit allows to develop games and applications in c language. It is common for these to fail through simple old age or due to other faults in the computer, in particular failure of the circuit that generates the multiple power supply voltages needed by the 4116s. Spectrum didnt show divide screen and also nmi button didnt work. Tynemouth software vintage computer repairs, accessories, kits. Fixing a poorly zxspectrum part 5 l break into program. As they simply dont make spectrum ulas anymore, then unfortunately if the ula has failed, then options for. Kodi archive and support file community software vintage software apk msdos cdrom software cdrom software library console living room software sites tucows software library shareware cdroms software capsules compilation cdrom images zx spectrum doom level cd. This was arguably the most popular computer in british history and. It is valid for all build standards, fitted with either 16k or 48k bytes of dynamic ram memory. Two major modifications have been implemented on the spectrum boards. Zxtunes it is worlds biggest zx spectrum 8bit music collection. The world of spectrum faq, maintained by arjun nair.
With a densely populated board such as the zx spectrum, as. I suspect ic7 and ic16 two ram chips on d1 but first, taking a tip from the lil old zx spectrum 48k. Timex fdd3, when power on, disk driver try to read the disk but it stops at few second. The obsolete memories 4116 use three power supplies 5v,5v, 12v that must be applied in a particular sequence worth the integrity of the chip. A block diagram of the complete zx spectrum microcomputer is given below. In the uk, the zx spectrum was one of the most popular early home computers of. The internet archive software library is a large collection of viewable and executable software titles, ranging from commercially released products to public domain and hobbyist programs. So if ic10 is faulty, then bit 4 of any byte in memory will be affected.
The 16k version is wired so that it can be expanded to 48k by the addition of a number of appropriate plugin ics. Jan 07, 2015 a short video covering the diagnosis and repair of a ram fault on a rubber key 48k spectrum. Apr 21, 2017 how to quickly diagnose 48k ram failures, ninja style april 21, 2017 brendan hardware most of you will be used to the distinctive power on screen of the 48k spectrum, where the screen goes black with a white border, and for a fraction of a second vertical red bars can be seen, before the screen clears to the message. I removed all the lower bank ram chips and plugged the power supply. If it is found that keys go faulty when warm and the ic1 5c1126c001 ula is ok, replace the membrane. Obviously from bidding portal and obviously i wasnt sure if it is in a working state. Here is a simple program that can help in the diagnosis of ram faults in zx spectrum computers. Now is the time to take the plunge and start cutting tracks.
It was a bit thrilling i know but some words of explanation are needed. Carries full assembler listings of the zx spectrum, zx80 and zx81 roms. This clon only have one ram bank made by 4164 chip. On spectrum pluses the fault of some keys not working, especially the keys on the bottom row. A short video covering the diagnosis and repair of a ram fault on a rubber key 48k spectrum. December 18, 2012 arjun leave a comment go to comments. The lower 16k of ram in 48k and 16k zx spectrum computers is provided by eight 4116 dram ics. Zx spectrum, no 5v repair when repairing something like a zx spectrum, its good to run it on a soak test for a while. New or replacement ram for the spectrum basically comes in three types, of which you can mix two of the types. Welcome to this wiki with information about the zx spectrum, for repair, maintenance, upgrades and more.
Normally when you see screen corruption like that on a spectrum it is a ram fault, it is in the shared memory bank that provides both the screen. Spectrum faq, 301105 since the faq is no longer maintained, for technical details you may want to see the tech info wiki. And the spectrum lives on, with new games and hardware. Brendan alford the author of the zx diag software i had been using for testing confirmed the ram hypothesis and referenced an article he had written about zx spectrum ram. Repair and restoration of a donated rubber key sinclair zx spectrum 16k. Repair and refurbishment service for your rubberkey zx. The replacement ram is lower power consumption and far less likely to fail. Obviously, this unit has quite a past but a lot of these quickfixes are made originally by sinclair itself. Having a set of schematics or even better a full service manual is the good thing to have before starting any repair. A cure without having to replace the membrane can sometimes be achieved.
Zx spectrum ram paging interrupts with 128k models. The zx diag cart comes with the zx spectrum diagnostics software, developed by dylan smith and brendan alford. Most spectrum software has been converted to current media and is available for download. See fig 28 for spectrum and fig 38 for the spectrum plus keyboards. The upper ram can be disabled to check if the computer then works ok as a 16k machine see indepth guide links below.
May 28, 2018 zx spectrum, no 5v repair when repairing something like a zx spectrum, its good to run it on a soak test for a while. Furthermore, the cartridges themselves acquired a reputation for unreliability, and publishers. The zx microdrive system was released in july 1983 and quickly became quite popular with the spectrum user base due to the low cost of the drives, however, the actual media was very expensive for software publishers to use for mass market releases by a factor of 10, compared to tape duplication. Tested with an extensive suite of zx spectrum software. These lists are now a bit out of date, but i have left them here for referece. Games and entertainment software for the zx spectrum. In this retro teardown, we will look at the most iconic computer of british history the zx spectrum. Whether you want to just get a faulty spectrum back up and running, or need a ula replacement for a new clone, then the vla82 is. It uses a modern sram ic and is far less likely to be damaged in the situations described above. Using the jsmess emulator, users can boot up an emulation of the given title and use it in their browser.
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