Editing Atari 65XE Troubleshooting Guide (section)

== Display & Chime Diagnostics ==

The 65XE should display a blue READY prompt and beep on successful boot.  
If not, use the following table to narrow down the fault:

{| class="wikitable styled-table"
! Symptom !! Likely Cause !! Action
|-
| No video, no sound, power LED off || Dead PSU, blown fuse, bad switch || Test/replace PSU, check fuse, clean switch
|-
| Black screen, power LED on || RAM, CPU, ROM, or custom chip failure || See “Black Screen” flowchart below
|-
| Solid colour screen (no text) || ROM or RAM fault || Reseat/replace ROM, test RAM
|-
| Garbage characters, unstable display || RAM fault, bad socket, bus contention || Swap/test RAM, clean sockets
|-
| Rolling/no sync video || Bad GTIA, ANTIC, or crystal || Swap GTIA/ANTIC, check clock
|-
| No beep at power-on || Bad POKEY, speaker, or CPU || Test/replace POKEY, check speaker wiring
|}

=== “Black Screen” (No Boot) Flowchart ===
# Confirm +5 V at mainboard and ICs.
# Check for a brief beep or click at power-on (if present, CPU/ROM likely running).
# Swap/feel GTIA, ANTIC, CPU (6502C), and POKEY in turn (if socketed).
# Reseat or substitute OS ROM and BASIC ROM.
# Test RAM chips (see below).
# Inspect for shorted decoupling capacitors or burnt resistors near the power input.