Editing Atari 2600 Troubleshooting Guide (section)

=== Black Screen - No Display ===
'''Symptoms:''' TV shows black screen, may have sound

This is the most common Atari 2600 failure with multiple potential causes:

'''Diagnostic Flowchart:'''

# '''Verify sync signal present:'''
#* Analog TV: Screen appears "tuned" (fuzzy black, not static)
#* Digital TV: May show "No Signal" even with sync present
#* If no sync, proceed to TIA testing

# '''Test with known-good cartridge:'''
#* Try multiple cartridges
#* Clean cartridge contacts thoroughly
#* If one cartridge works, problem is cartridge-specific

# '''Check cartridge slot:'''
#* Inspect 24 pins for bent/pushed back contacts
#* Clean with isopropyl alcohol and credit card method
#* Verify plastic tabs present for dust cover activation

# '''Test TIA chip:'''
#* TIA generates all video and audio
#* Most common IC failure on 2600
#* Swap with known-good TIA or donor console
#* No substitute parts available

# '''Test RIOT chip:'''
#* Contains 128 bytes system RAM
#* Faulty RIOT causes no boot
#* Less common failure than TIA
#* Test by substitution only

# '''Test 6507 CPU:'''
#* Rarely fails but possible
#* Check for clock signal on pin 39 (3.58MHz)
#* Verify reset on pin 40 goes high after power on