Editing Sinclair ZX Spectrum +2 Troubleshooting Guide (section)

== Keyboard faults ==

The +2 uses a membrane under a moulded keyboard, and membrane failure is the usual cause of dead keys. A completely unresponsive keyboard is a reported fault mode.<ref name="tyne" />

Diagnosis follows the same logic as the 48K machines: a dead block of keys points to one membrane tail or its connector rather than to a chip. Check the tails are fully inserted and undamaged before suspecting the ULA. Replacement +2 membranes are still manufactured.

When refitting the tails, ease them in with a slight side-to-side motion and make sure they are square and fully home.<ref name="sm128" />