Editing Atari 800XL Troubleshooting Guide (section)

=== POKEY fault signatures ===

POKEY fails in tell-tale ways: the keyboard is dead but sound still works; or keyboard and sound work but '''SIO''' does not &mdash; sometimes SIO fails only at divisor&nbsp;0 (the fastest rate) yet works at divisor 4/6/8. '''GTIA and ANTIC are largely binary''' (working or dead); SALLY can show subtler faults.<ref name="a8flt">[https://8bithardware.wixsite.com/website/post/atari-8-bit-400-800-xl-xl-pictorial-fault-guide Atari 8-bit (400/800/XL/XE) pictorial fault guide], 8bit-Hardware; [https://atariprojects.org/2025/01/01/label-the-6502-cpu-antic-gtia-pokey-and-pia-chips-for-easier-troubleshooting-using-a-multimeter-or-oscilloscope-10-15-mins/ Label the 6502 CPU, ANTIC, GTIA, POKEY and PIA Chips], Atari Projects; and [https://www.atarimania.com/pgefaq_chapitre.awp?id=14 What are SALLY, ANTIC, GTIA, POKEY and FREDDIE?], Atarimania. Source for the Star Raiders diagnostic coverage (ANTIC/CPU/GTIA), the POKEY fault signatures (keyboard vs SIO), the GTIA/ANTIC binary behaviour, and the reseat-first / RAM-and-socket-most-common guidance.</ref>