ZX Spectrum +3e Mod

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This is a guild on how to install the ZX Spectrum +3e Modification to a ZX Spectrum +2A/B and +3 computers. This guild is manly designed for the ZX Spectrum +3, as that is the computer I have done the modification two.

First you will need to open up the ZX Spectrum by removing the 5 screws on the base of the unit, and then remove the two screws connected to the floppy drive on the right hand side of the ZX Spectrum +3.

For a +2A/B you will just need to remove the screws located on the bottom.



Once you have removed the screws you and removed the top half of the ZX spectrum, carefully removing the keyboard ribbon cables and the LED connector you will see the following



At this point you will have access to both of the ROM chips and the Z80 Processor, if you are not fitting and IDE interface then all you need to do is to remove the each of the Rom chips, using a flat head screw driver and then replace them with the Roms that you have purchased or burned yourself.

At this point you have 2 options, if you are going to us an external source of power for the IDE device then just fit the two roms back in making sure that you have them in the correct locations and the correct way round and most of the mods for the +3e I have seen so far require a daughter board to be fitted to the Z80 chip socket and then the Z80 processor plug in to the daughter board.

If you are planning on getting power form the ZX spectrum directly then you will need to remove the ZX Motherboard flip it over and locate the power connector for the floppy drive on the underside of the ZX Spectrums motherboard.

Once you have located this, then you will need to solder 4 wires on to the underside of the floppy drive power connector to provide power for the IDE drive.

Depending on what you are going to use to power the IDE device then you a floppy disk power connector or a standard Molex connector to power the IDE drive.

In the case of this guild I used a floppy drive power connector to a CF card adapter.



You have to check to make sure that the voltages are correct in my case the yellow wire is +12v and the red wire is +5v, and both of the black wires go to common ground. If you get the wiring wrong you could damage the spectrum and the drive you plug in to it.

Once you have the cables solder to the underside of the ZX Spectrums motherboard flip the board back over and screw the board back in to the lower part of the ZX Spectrums case.

If you have already fit the two replacement rom chips with the two new Eproms, fit the daughter board and refit the Z80 in to the socket on the daughterboard.





Once you have done that install the CF card reader and connect it up with a 40 pin IDE cable.

When I installed the card reader in to my Spectrum +3 I connected it to the read screw point on the floppy drive. You may find that there is no screw in this screw point, that was because when Amstrad and Sinclair where penny pinchers and wanted to keep cost down so you may find when you go inside your +3 that this screw is none existent.

At this point power your Spectrum up with the keyboard detached and make you it comes up correctly. If it does then reassemble your spectrum and enjoy the enhanced +3 rom.

You should find that you get the normal spectrum start screen with a little extra text, Saying that it has detected a number of IDE devices, also listing the AB and M drives.

If you do not install a CF card or other IDE device then on the ZX spectrums home screen it will say there are 0 IDE devices.

Side note, I have found that if you have a CF card or other IDE device connected and are using the DIVEnjoy MMC then the spectrum will not boot until you either disconnect the DIVEnjoy MMC or remove the compact flash card in my case. I can leave the connector in place.

I suspect there is some firmware clash between the +3e ROM and the ROM / Firmware that the DIVenjoy MMC is using.

If you decide to do this mod on your spectrum you could locate the CF / IDE device some where you can get to without having to take the top of your speci every time you want to use a device that clashes with the IDE device. Or you could fit an IDE port to the side or the back of the spectrum.

For more information on the ZX Spectrum +3e see the following link Retroisle