Reads from port 0x7ffd cause a crash, as the 128's HAL10H8 chip does not distinguish between reads and writes to this port, resulting in a floating data bus being used to set the paging registers.ĭue to a bug either in the 128's HAL10H8 chip or in the PCB, memory banks 1, 3, 5 and 7 are contended (and the rest uncontended) as opposed to 4, 5, 6 and 7 as documented in the service manual. The bits are described in the table below: The paging logic decodes the address bus partially (uses A15 and A1 lines only), so the exact port is 0xxx xxxx xxxx xx0x. Paging is controlled by performing I/O writes to ports 0x7ffd. The 32KB of ROM and 128KB of RAM can be paged into the memory space as shown in the diagram below: The memory space of the ZX Spectrum 128 is divided into four 16KB pages.
#Zx spectrum 128k games2girls serial#
#Zx spectrum 128k games2girls generator#
Sound: AY-3-8912 3 channel, 8 octave Programmable Sound Generator and "beeper".Graphics: 256 × 192 pixels, 16 colours, attribute based.RAM: 128KB of Dynamic RAM, arranged in 8 pages of 16KB.ROM: 32KB ROM, arranged in 2 pages of 16KB.Processor: Zilog Z80A microprocessor clocked at 3.5469MHz.The angle of the stripes was measured as being at 24-degrees.
The exact Pantone colour values couldn't yet be retrieved. One of the iconic elements of the design, brought over from the 16k/48k design, is the coloured stripes symbol at the bottom right of the keyboard in the colours Red, Yellow, Green and Cyan. New products are being added every month.Īlso, please support our work by spreading info about it.The industrial design was by Rick Dickinson, who had previously done the industrial design for the ZX80, ZX81, ZX Spectrum 16K/48K and Spectrum+. If you want to get retro gear or hardware modules, please visit our shop ZX Spectrum 128k +2 – GREY from pit on Vimeo. Here is how it works with Lothareks Divide2k14 After a few hours of work, I’ve got a beautiful Grey ZX Spectrum 128k +2 I’ve also soldered on a proper power socket.Īaaand that’s it. The keyboard was in very good shape but a bit “buggy” lol Keep in mind that it still can be improved. However, after these two simple mods, the screen started to look way better. I skipped creating a new LC circuit simply because I didn’t have a 15mH inductor on a shelf.
It can be done by redirecting another nearby ceramic capacitor(C31 if I remember correctly) straight to one of the TR2 transistor legs.
The second problem was also easy to solve. The first is an old inductor (L2) circuit, the second is audio interfering with the composite signal, and the third (ghosting) is a lack of a new LC filter near the TEA2000 encoder.Īn old inductor circuit can be easily turned off by simply removing a ceramic capacitor C3. According to smart guys from internetz this poor quality of the composite output is caused by at least three factors. Here is an example of a properly resoldered TR4.Īfter this operation composite signal started to work again but to my surprise(again), it wasn’t much better than a blurry RF that I’ve already tested. In my case, transistors TR4, TR5, TR7, and TR8 had to be resoldered. Looks like guys in Amstrad had a lot of transistor suppliers and got kinda lost in it 😀 It turned out that on rev.3 mainboards, very often transistors are soldered on in the wrong way (emitter and collector swapped). That surprised me a bit but let’s get to the details. I’ve started digging a bit and found out that there are quite a few manufacturing mistakes. The only output I’ve got was a distorted mess on the screen. I was assuming that the video output quality will be much better. The next step was to get a video signal through monitor output. I’ve connected speccy via RF modulator and I was greeted with a boot screen YAY! I’ve also cleaned chip pins with a small, metal rotary brush.Īt this moment I wanted to test if everything works fine after cleaning. Just for a comparison, new sockets on the left 😉 I usually remove chips from their respective sockets before cleaning … and surely I did it this time too … however, I had to remove all sockets instead of chips only. Here are a few shots of PCB before I’ve put my hands on it (nice and dirty) 🙂įirst things first, which in this case is cleaning. Several C64 repairs later, I’ve finally had some time to have a look at this unit, and here is how it looked: But hey! If I knew that, it wouldn’t be a challenge riiite?Īfter nearly two weeks I became a happy owner of +2 Grey in an unknown state. Obviously from the bidding portal and obviously I wasn’t sure if it is in a working state. The real story is that I had an occasion to get a Grey ZX Spectrum 128k +2. Soooo, this is a story about a little boy who was never born
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