A place to discuss the ZX80's and ZX81's younger brother - the Sinclair ZX Spectrum
- Posts: 280
- Joined: Tue Dec 19, 2017 10:02 pm
- Location: St Albans, UK
@alcid34: I've looked very briefly on your schematic and A9 of AY-8-8910 is not connected anywhere. A9 must be kept low, otherwise the AY chip will ignore any address request. Any input designated as TEST should be left open (i.e. floating).