Editing Atari 2600 Troubleshooting Guide (section)

=== No Power - Completely Dead ===
'''Symptoms:''' No LED (Jr. model), no TV signal change, no sound

'''Diagnostic Steps:'''

# '''Test power adapter:'''
#* Set multimeter to DC voltage
#* Black probe to barrel outer ring
#* Red probe to center pin
#* Should read 9V minimum (often 12-14V unloaded)
#* If below 9V or unstable, replace adapter

# '''Test power jack:'''
#* With adapter connected, measure voltage at jack terminals on PCB
#* No voltage indicates broken jack or cold solder joint
#* Reflow solder joints, adding fresh solder
#* If jack is physically broken, replace with standard 3.5mm barrel jack

# '''Test power switch (6-switch models):'''
#* Measure voltage on both sides of switch
#* Should have voltage on both sides when ON
#* If voltage only on input side, switch is faulty
#* Work switch 100+ times to break oxidation
#* Apply DeoxIT if oxidation persists

# '''Test 7805 voltage regulator:'''
#* Locate 7805 (lower left on most boards)
#* Black probe to mounting screw (ground)
#* Red probe to left pin: Should read 9V+ (input)
#* Red probe to right pin: Should read 4.85-5.15V (output)
#* If input present but no output, 7805 is faulty

# '''Test main filter capacitor:'''
#* Large 2200µF capacitor near power circuit
#* Measure voltage across terminals
#* Should match 7805 input voltage
#* If significantly lower, capacitor is failing