Member Avatar for scribeman01

Greetings to all -- I have a Compaq 6515b notebook that boots, runs fine.
However, when I shutdown, the display remains in a dim, black screen state when using the charger. If on battery, this does not happen. If I replug the charger back in, the notebook will boot immediately - - no need to use the power switch. There are also BIOS issues where the notebook is not holding dates and resets itself back to 1980, even after I have changed the battery. I have tried adjusting the power settings with no success. There is a very minor chip in the LCD power connector to the motherboard on its edge, but all fingers within the connector are intact. I did observe some oxidation in the power switch area of the the mb which I cleaned up. Any thoughts - - or am I dealing with a dying motherboard?

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The behavior described (different shutdown behavior on AC vs battery plus a CMOS/RTC that does not retain time) is classic for a failure in the motherboard power-management/standby domain rather than a simple OS setting. That narrows the fault to one of a few places: the embedded controller (EC) or power‑FETs that control the panel/inverter, the 5V standby rail, or the RTC backup trace/solder joint — not the LCD content or GPU itself.

Practical, safe diagnostic steps to narrow it down:

  • Test with battery removed: connect AC only, boot, then shut down and observe whether the panel/inverter stays faintly lit.
  • Try an external monitor and shut down: if the external goes completely dark while the internal panel remains lit, the inverter/panel or its power driver is suspect.
  • Power‑drain cycle: remove AC and both batteries (including coin cell), press-and-hold power 20–30s, then reconnect battery only and test shutdown behavior.
  • Inspect visually (with power removed) around the DC jack, coin‑cell holder and the display cable: cracked solder pads, lifted traces, bulged caps or corrosion often cause these symptoms. Pay attention to the small area you mentioned near the LCD connector.
  • If comfortable with meters, confirm the 5VSB and RTC Vbat lines are present/steady when AC is connected; do not probe the inverter HV outputs (dangerous).

Likely outcomes and realistic fixes:

  • If only the internal panel is affected, replacing the inverter board or the panel/cable often cures it.
  • If external and internal both misbehave, or the RTC Vbat line is missing despite a new cell, the motherboard power-management circuitry or EC is failing; that usually needs board-level repair or a donor motherboard. Given the machine age, cost of a replacement mainboard vs. buying a used/refurb laptop will guide the decision.

Caution: CCFL inverters create high voltages; avoid touching the inverter connectors when powered.

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Member Avatar for rubberman

How old is this system? Assuming these issues have appeared fairly recently, I can only assume that the system is starting to suffer hardware failure.

Member Avatar for scribeman01

Thank you Rubberman. It's not a "youngster" - guessing about 2007ish. I already cleaned up dust build up in the fan & heatsink. I am tending toward hardware board failure myself - - never saw this type of shutdown issue before with the monitor staying on after notebook shuts down ...

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