Editing Atari Portfolio Troubleshooting Guide (section)

=== Blank Display (No Text Visible) ===

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{| class="wikitable styled-table"
|+ Blank Display Diagnosis
|-
! Symptom !! Likely Cause !! Action
|-
| Screen completely blank, unit appears to power on (key clicks audible) || LCD contrast misadjusted || Adjust the contrast potentiometer screw (accessible beneath the display window bezel). See [[Atari Portfolio General Maintenance#LCD Contrast Adjustment]].
|-
| Screen blank, no key clicks || Power failure || Check batteries and power ribbon cable.
|-
| Screen blank, contrast adjustment has no effect || LCD bias voltage failure || Check the charge pump circuit components. The small electrolytic capacitors in the LCD bias circuit may have failed. See [[Atari Portfolio Capacitor Replacement Guide]].
|-
| Faint ghosting visible but no clear text || LCD driver or ribbon flex failure || The flex connection between the LCD glass and driver board may need reseating.
|}