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When I plug in AC to my old Toshiba laptop red and white LED comes on. If I press the power button to turn the PC on there will be a blinking white light in between the power and charging LED which red and white but not fan spin. Or display on the screen. I have even tried connecting to external monitor yet no display. Pls help me

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  • Latest Post Latest Post by rproffitt

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reported that the AC lamp and charging LED come on but pressing power only produces a blinking white LED; the fan never spins and neither the internal nor an external display show output. ’s suggestion to try inexpensive, non-destructive checks (small coin cell and a power-discharge) is a reasonable starting point, but the symptom set more often points at a power-delivery or motherboard issue that prevents the system from reaching POST.

A focused diagnostic sequence (start at the top and stop when something changes):

  1. Verify the adapter actually delivers rated DC voltage with a multimeter or try a known-good compatible adapter. An LED on the adapter does not guarantee correct voltage under load.
  2. Isolate power sources: remove the main battery and attempt AC-only, and vice versa if possible; perform a short power-discharge with both sources removed to clear the embedded controller.
  3. Reseat memory modules and test with one stick in each slot; a bad or loose DIMM can prevent POST.
  4. Disconnect non-essential devices (HDD/SSD, optical, Wi-Fi) so only CPU, one RAM stick, and display circuit remain.
  5. Inspect the DC jack, fan connector, and motherboard for loose solder, corrosion, bulging capacitors, or burn marks; check whether the fan header shows voltage when power is applied.
  6. Note blink/beep patterns and compare to the service manual for that exact Toshiba model (blink codes map to specific errors).

Interpretation notes: if the adapter measures correctly but nothing powers (no fan, no POST), the DC-in circuitry or main power MOSFETs/VRMs are suspect. If fans run but no display, the GPU/BIOS/RAM path is likelier.

If basic checks fail, board-level diagnosis or replacement is next; factor repair cost vs. laptop value. Always discharge the system, remove batteries before opening, and follow ESD precautions.

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You left out details that might help. Always supply full model numbers, age and prior service. For example if it's years old I always try a new CMOS battery (cheapest part, might fix it, worth the risk.) Some feel that spending 1 dollar is too much a risk and maybe they are telling you they want a new laptop.

The symptoms are not a sure sign it's this or that but I'd try the new battery then the usual soft reset which is simple. Remove the power adapter, unplug the big battery then press and hold the power button for 60 seconds. Release, slip in the big battery, apply power and re-test.

commented: 1+ for CMOS battery +15
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