Retrofitting An Amstrad CPC6128 With A Floppy Emulator

In the home computer boom of 1980s Britain, you could describe Amstrad as the third-placed home-grown player after Sinclair and Acorn. If you were a computer enthusiast kid rather than a gamer kid, you wanted Acorn’s BBC Micro, your parents bought you Sinclair’s ZX Spectrum because it was cheaper, and you thought the Amstrads were cool because they came with a better monitor than your family’s cast-off 1970s TV.

Amstrad were not a computer company headed by a technical wizard, instead they were a consumer electronics company whose founder [Alan Sugar] had a keen nose for the preferences of the consumer. Thus the Amstrad machines were different from some of their competitors: they were more polished, more appliances than experimental tools. Mass storage devices such as tape decks and floppy drives were built-in, every Amstrad came with its own dedicated monitor, and keyboards were decent quality as you’d see on a “proper” computer.

The high-end Amstrad model was the CPC6128. It came with a 3″ floppy drive, and of most interest, it could run the CP/M operating system. If your parents bought you an Amstrad CPC as a 1980s teen, it wouldn’t have been this one, so they are considerably less common than their 64k brethren with the cassette deck. One has found its way into [Drygol]’s hands though, and because the vintage 3″ floppies are unobtainable nowadays he’s fitted a floppy emulator board that stores data on an SD card.

In a sense, in that this is simply the fitting of an off-the-shelf board to a computer, it’s Not A Hack. But misses the point. This is an unusual home computer from the 8-bit era and his write-up is as much a teardown as it is  a howto. We don’t often get to see inside a 6128.

Fitting the board required the fabrication of a cable, with some very neat soldering work. The board has an LCD display, which is mounted in the floppy opening with a 3D printed bezel. The result is a very usable retro computer, without too much in the way of wanton remodeling.

This is probably the first real Amstrad 6128 we’ve shown you, but that hasn’t stopped enthusiasts making a clone with original chips, and another on an FPGA.

 

18 thoughts on “Retrofitting An Amstrad CPC6128 With A Floppy Emulator

  1. I wonder how he is getting a CPC6126 to run with an LCD screen. VGA converter?

    I have one of these (CPC6128) that I had to fix (RAM problems). I use a VGA converter, a switch-mode power supply and I installed a 3.5″ floppy to replace the 3″. I also made an IDE port that should be good for drives up to 128GB but I need to replace one part (LDO) to get it to work properly. I have the replacement part now but not the room on the bench cos other projects. I also made an interface to drive a SD card through the printer port but I gave that up and went to IDE as CPM is easier to port to FAT than SD.

    Here are some pics –
    https://hackaday.io/project/3462-retro-computer-repair-hack-1

      1. We don’t have SCART here as it’s a European thing. I tried everything to connect my CPC6128 to a monitor. I even found a monitor with many input types (VGA/Composite/Component) in the hope it would sync at 50Hz.

        I could get a monochrome picture with composite but it would never work via the VGA connector because of the composite sync. VGA expects separate Horizontal and Vertical sync.

        Then I made a baseband modulators with an AD724 and that worked but it was not the best because of the AC coupling of the RGB signals.

        I bought an AD722 which has DC coupled inputs and I was going to try that but instead I bought a VGA converter and that is mostly ok but it probably wont work with games that use 6845 register based rater effects.

        Has anyone tried the AD722??

    1. Simplest way to get a disk up and running with low effort/cost is using a tape cable. I wrote a tool a couple of years ago that converts a disk image to a tape image that you can play from your soundcard or a phone into the CPC and it automatically writes that image to a disk.

      http://www.cpcwiki.eu/forum/applications/dsk2cdt2disc-get-disc-images-onto-your-cpc-via-a-tape!/
      https://github.com/pelrun/dsk2cdt2disc

      …uuunfortunately my CI provider went belly-up so I don’t actually have any binary releases currently. I should probably fix that.

      1. I ended up doing this the hard way and swapped the 3″ Floppy Drive for a 3.5″

        I have a dual boot computer that has Win7 for normal use and Windows XP for formatting copying to 3.5″ disks.

        Win7 doesn’t allow direct register writes that are needed to write to, or format the disks to a non-IBM standard.

        I use an application called CPCDiskXP.

        The annoying part about this setup is that it uses a propriety disk image file format – just one file for the whole disk.

        I have made an IDE interface that will drive a 127GB hard drive and CF cards and use plain old FAT32 so that I can drag and drop files onto the CF card in windows. I can use the 127GB to store everyThingEverWrittenForTheCPC.

        I have to make a PSU (and VGA converter) project box so I have one power switch for the CPC and the IDE as the IDE can’t get enough voltage from the expansion port.

        This might get me on my way again – I will go order a SMPSU now or perhaps a torroidal and do it linear.

    2. If you want to connect the Amstrad CPC / Schneider CPC to a VGA monitor, you can use one of those cheap CGA->VGA converters. It will work with most of the software for the computer, but if you use it with newer productions like demos (e.g. Batman Forever), it won’t work with all hardware tricks, they are using.
      I wrote a small tutorial on how to connect such a converter to the CPC: https://www.octoate.de/wp/articles/connect-cpc-to-vga-display/

      1. That’s the exact converter that I ended up using. I want to extend the buttons and put it in a project box with a power supply.

        I swapped the 3″ FDD for a 3.5″ FDD that only uses 5 Volts so I no longer need the 12 Volt supply.

  2. I had one of these great machines, fitted with ROM port. I had wordprocessing, databases, compiler, spellcheck instantly available 2 seconds after power-on. Take that, Pentium computers.

    I had a 5.25″ floppy drive,with a massive 800 KB capacity per side. Whopping 1.6 Mb per disc!

    Internal floppy failed me, so fixed belt with a bit of bike tubing.

    Sold it eventually because it had a low WAF. Like selling a part of myself and my childhood. Still miss it today!

  3. no mistakenly tosse dmy CPC6128 and its little brother the 464 into the bin in perperation for moving a few years back – along with a bucket loas of atarl 2600 cartridges – yes it was an attempt to please my new wife – pointless exercise in hindsight …. should have tossed her instead (took me a couple of years to do that)

    1. I cannot understand what kind of a woman would want from a man to toss away collectables, especially ones that have big sentimental value. Sorry for your loss (and I don’t mean your ex-wife).

  4. I had a ZX Spectrum 3+, which was practically a rebranded Amstrad.

    The 3″ drive was dud, but a regular 3.5″ floppy drive fit and worked with no issue. (I didn’t have many 3″ disks, so was no issue.)

    I also made a simple IDE lead which I could switch between my 2+ and 3+ (I think it ran the IDE drive at 8 or 16 bit – half the full IDE bus, thus half the capacity accessible, but even with a 1GB drive, 500MB could store my whole Speccy collection many times over!).
    Today I’d throw in a CF card and be done with it.

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