Member Avatar for tngreg

Ok this unit has the classic symptoms of an inverter going bad when plugged into the power source, BUT when you only run the laptop on battery the screen does not blank out (go faint).

Typically when the inverter goes bad you can still see the image very faintly.
This is a DELL Inspiron 8600.

Any clues?

Thanks
tngreg

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Dani AI

Generated

Building on 's inverter suspicion and / pointing toward power/brightness controls, treat this as a methodical isolation problem rather than guessing a single cause. The usual culprits are either hardware in the display power path (inverter, CCFL lamp, DC jack, AC adapter, LVDS cable) or firmware/driver power management that changes behavior when AC is present.

  • Reboot into the BIOS/POST screen and compare appearance on AC vs battery. A brightness change that appears in BIOS points to hardware or firmware/ACPI at a low level; if BIOS is steady while Windows changes, suspect drivers or utilities.
  • Attach an external VGA/DVI/TV display. If the external output stays normal on AC but the internal panel dims, the fault is inside the lid/display chain. If both dim, look at adapter/board-level power or GPU.
  • Test with battery removed (AC only) and with AC removed (battery only). Different results from those two states narrow the fault to the adapter/DC jack/regulator versus the battery-fed path.
  • Swap the AC adapter or check its unloaded/loaded voltage. A weak or out-of-spec adapter or a loose/broken DC jack can cause odd AC-only symptoms.
  • Update BIOS, chipset and video drivers and disable vendor power utilities temporarily to rule out software-managed brightness or adaptive features.
  • If hardware failure is confirmed on an older Inspiron (CCFL + inverter), inspect the inverter cable at the hinge and the DC jack. Inverter or lamp replacement is common, but inverter circuits carry hazardous high voltage — use the service manual or a professional repair shop and match exact part numbers.

Document which of the above tests reproduce the symptom before ordering parts or seeking shop service; that information lets a technician target inverter, lamp, cable, or power-rail faults quickly.

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Member Avatar for cohen

This is normal, the contrast is going down... it is a setting.

I do it on my laptop because then the battery lasts longer!

When it is plugged in, it is bright....

OK, well, when you unplug it, adjust the contrast. it would be Fn + *sun symbol* up / down...

Hope this helps :)

Cohen

Member Avatar for OlyComputers

Is the backlight going off or just diming?

I remember an HP laptop that was set like this by default, a weird backwards setting where the screen brightness went down on power instead of battery. Snoop around the Power settings in control panel and see if anything stands out, as well as cohens suggestion of adjusting the brightness.

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