Editing Macintosh TV Troubleshooting (section)

== Chime but No Video ==
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Video Issues After Successful Startup Chime'''
|-
! Symptom !! Possible Cause !! Recommended Action
|-
| Chime, no video, drive activity || CRT failure, video circuit problem, brightness set to minimum || Adjust brightness/contrast, check CRT neck board, test analog board
|-
| Dim or faded display || Weak CRT, failing analog board capacitors || Check CRT heater glow, recap analog board
|-
| Distorted geometry || Yoke misalignment, failing capacitors, magnetic interference || Adjust yoke, recap analog board, degauss screen
|-
| Horizontal or vertical collapse || Deflection circuit failure || Replace failed components in H/V deflection circuits
|-
| Flickering display || Failing capacitors, cold solder joints || Recap analog board, reflow solder joints
|-
| No video but TV mode works || Logic board video circuit failure || Check logic board capacitors, test video RAM
|}

=== Flyback Transformer Check ===

The flyback transformer is a common failure point:
* Check for audible arcing or crackling sounds
* Inspect for cracks in the transformer body
* Measure secondary winding resistance if accessible
* Replacement requires exact match or compatible substitute