Editing Atari 65XE Troubleshooting Guide (section)

== Audio & I/O Failures ==

The POKEY chip (U7) generates sound and handles keyboard, serial, and paddle input.

{| class="wikitable styled-table"
! Symptom !! Likely Cause !! Action
|-
| No sound, but boots || Bad POKEY, speaker, or amp || Replace POKEY, test speaker
|-
| Keyboard unresponsive || Bad POKEY, keyboard membrane, or connector || Test/replace keyboard, check POKEY
|-
| Joystick port not working || Bad solder joint, trace break, or POKEY || Reflow joints, continuity test, replace POKEY
|-
| SIO (disk/tape) not detected || SIO connector, POKEY, or 74LS logic || Clean connector, check U5/U6 (logic)
|}

* Test the speaker by applying 1.5 V briefly; if it clicks, the speaker is good.
* For keyboard faults, test continuity from the keyboard connector to the POKEY IC.