Member Avatar for aqua687

Hi,

A year and half old Toshiba Satellite C850 laptop, abruptly turned off while running normal. It does not turn on any more. Power light turns white and then another amber light comes up a few seconds later. The LCD remains off. HDD is activated but the cooling fan does not work. Removed the battery and power inlet and pressed the power button, but it does not work. Can any one suggest that a faulty fan could stop the computer from turning on? Any help would be appreciated.

Thanks.

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  • Latest Post Latest Post by DMR

Dani AI

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Brief summary and safe correction of earlier suggestions: reported a machine that shows power activity but no screen or fan. Ignore the advice from to "feel the processor" while powered — that is unsafe and not a reliable diagnostic. is correct that a failed fan can lead to later, heat‑related damage, but a dead fan alone does not always explain a no‑POST condition. Below is a practical, safe checklist to narrow the fault without guessing.

  1. Basic power checks (safe, high yield)

    • Verify the AC adapter with a meter or a known‑good identical adapter. A faulty adapter can power some subsystems while failing others.
    • Remove battery and try AC-only. Hold power for 10–15 seconds after disconnects to discharge caps, then try powering.

  2. Observe indicators

    • Record exact LED colors/blink pattern and any beeps. Those sequences are diagnostic clues for service technicians.

  3. Minimal component isolation

    • Reseat or test with one RAM module at a time and disconnect the HDD/optical drive. Faulty RAM or peripherals often stop POST but let fans spin.
    • Attempt an external monitor (VGA/HDMI) or shine a bright light on the LCD to check for a faint image (backlight failure).

  4. Fan and physical inspection (power off, battery out)

    • Open the access panel, confirm the fan cable is connected and free of obstruction. If the fan is getting power but not spinning, the fan assembly is cheap to replace.
    • If the fan connector shows no voltage when powered, the motherboard fan/PWM supply or EC controller is suspect.

  5. When to stop and get help

    • If adapter is good, fan connector has no power, or there are burn marks/capacitor bulges, stop and consider a professional repair. Board‑level faults (power rails, MOSFETs, EC) need diagnostics and tools most users do not have.

Notes and cautions

  • Do not probe powered motherboard components with bare hands; use proper ESD precautions. Swapping laptop CPUs or doing BGA rework is not a casual repair. If the machine is valuable or you are unsure, a local repair shop can do safe voltage checks and identify whether a simple fan replacement or a more expensive board repair is required.

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Member Avatar for faroukmuhammad

Turn it on and feel the processor (but you should be careful it can get very very very very very hot); if it doesn't get hot then it is dead try another processor.

Member Avatar for DMR

HDD is activated but the cooling fan does not work... Can any one suggest that a faulty fan could stop the computer from turning on?

Depending on exactly when the cooling fan failed (and how much longer you used the laptop after that fan did fail), then yes- the fan failure could certainly have cause other components in the laptop to overheat and fail as well. (Laptops are much less forgiving than desktop systems when it comes to questions of proper cooling.)

I do see that you've posted this same question on a Yahoo support site, and that you've gotten an answer there indicating that the fan is not the issue.
However, the person who replied to your question there didn't take in to account what I said above: if you ran the system too long without noticing that the fan had failed, other hardware components may have been damaged.

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