Editing Sinclair ZX Spectrum+ Troubleshooting Guide (section)

== Common fault catalogue ==

* '''Machine dead after using an interface''' — edge-connector damage from hot-plugging; check TR4 first, then the RAM.
* '''White or patterned screen''' — DC-DC converter (TR4/TR5/coil) or lower RAM.
* '''Herring-bone pattern''' — −5 V missing; change TR4.
* '''Thin vertical dashes on black''' — lower RAM, or ULA legs.
* '''Blank black screen''' — upper RAM.
* '''Character break-up when warm''' — ULA.
* '''Won't load, bars but no filename''' — tape azimuth.
* '''No sound''' — ULA, then speaker, then TR7/D9.
* '''No colour''' — LM1889, or an SN-series substitute in IC14.
* '''Dead keyboard''' — 5 V supply, then the R65–R69 10 kΩ resistors, then the membrane.
* '''Bottom-row keys dead (Spectrum+)''' — clean and re-pack the clamped ribbons.
* '''A key repeats endlessly (Spectrum+)''' — slacken the backing-plate screws nearest that key.
* '''Random resets when moved''' — power plug or socket.