This page contains technical information across a wide variety of topics that hopefully people will find useful.
Boring legal disclaimer: No responsibility is taken for any loss or damage resulting from advice given in these articles.
General Information
- ZX Spectrum Models and some basic technical info on each
- ULA types – what’s compatible with what machine etc.
- Spectrum compatibility issues (i.e. why won’t my game run!)
- Memory contention and the floating bus explained
- List of Z80 instructions, opcodes, characters and timings
- Inside the Prototype ZX Spectrum’s ROM
Maintenance
- Recapping your Spectrum
- Capacitor Lists: 16/48K, 128K/+2/+2A/+3
- Servicing your +2/+2A Tape deck
- Replacing the drive belt on your +3 FDD
- Refelting ZX Microdrive Cartridges
- Spare parts for all Spectrums
Repair
Upgrades
- Fitting an EPROM to a 16/48K Spectrum
- Upgrading a 16K Spectrum to 48K
- Upgrading esxDOS on your DivMMC device
- Modifying a +2A Sound socket to accept tape input (+3 standard)
- Adding an external tape input socket to a Grey +2 (thanks to Duncan Edwards)
- Issue 1 DIY 32K expansion board
Audio Modifications
Video Modifications
- Composite Mod for the 48K range
- How to fix Issue 1/2 yellow or blue screen tint
- Fixing vertical ‘jailbars’ on your 48K, 128K and Grey Spectrum +2
- Making your 128/+2/+2A/+3 RGB socket SCART compliant
- Modifying a +2A or +3 to output Composite on the RGB port
- Removing Blue/Yellow Ghosting from the 128/+2’s Video Output
- Modifying an Investronica 128 For Proper Composite Output
Other Modifications
- Rewiring your +2/+3 Joystick ports to Atari standard
- Applying the Unrainer/IN 7FFD fix to 128/Grey +2 machines
- Constructing an alternative PSU for the +2A/+3 machines
- Performing the IN FF mod on a +2A/+3 (restores rudimentary floating bus behaviour)
- Fixing Keypad Issues on an Issue 6K 128K Toastrack
- Unlocking Your Recreated Spectrum Bluetooth Keyboard
Technical References and Documentation
- ZX Spectrum Service Manual (includes Supplement No.1 – Issue 3B to 6A, and Supplement No. 2 – Spectrum+ Description and Upgrade Procedure)
- ZX Interface 1, Interface 2 and Microdrive Service Manual
- ZX Printer Service Manual
- 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
This has been copied from Ben’s website following his passing, in the interests of preserving the content.
Ben Versteeg’s guide to video fixes and cable pinouts for the 128/+2/+3 range. Contains information on how to construct your own SCART cables, correcting video related PCB errors on the Grey +2, detaching audio from the composite out on 128/Grey +2 etc.
Improving the audio quality on the +2A/+3, and +2B / +3B (by ZXGuesser)