Member Avatar for acarr

Hi I have a Toshiba Portege M405 Laptop that is just over a year old and just out of warranty.

The problem is that about 90% of the time when I hit the button to turn it on all that happens is the power light comes and nothing happens. Other times the power light flashes yellow and the cpu fan comes on full speed. I then hold the power button to get it to turn off and have to try again.

This can happen dozens of times before it will actually boot. Once it actually does boot the computer works perfectly until I turn it off again. Then its any body's guess when I can get it to start again.

Things I have tried:

-I have removed the hard drive, it still wont boot at all even to the bios.
-I have tried removing the memory one stick at a time and have run memtest on it. Came up fine.
-Have disassembled it and looked for loose connections or cold solder joints, re seated everything. This didn't change anything.

Thanks for any help that you might have.
-Alan

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Generated

Given the tests already described by and the replies from , and , the symptoms (no POST or a blinking power LED, fan at full speed, then perfectly normal operation once it finally boots) point away from the hard drive or RAM and toward the power/POST path on the mainboard: a flaky DC jack or adapter, a failing power switch or EC/BIOS handshake, or temperature-sensitive solder (dry/BGA joints).

Practical diagnostic sequence to try (in order of cost/risk):

  • Check the AC adapter first. Measure its DC output with a multimeter and, if possible, test with a known-good adapter of the same rating. Intermittent adapter output can cause exactly this behavior.
  • Inspect the DC jack and its solder points for movement or cracked solder. While trying to power the machine, gently wiggle the jack and note any change.
  • Try a full power bleed: remove battery and AC, hold the power button ~30 seconds, then reconnect AC only and try booting.
  • Attempt a minimal-boot: remove HDD, optical drive, wireless card and any extra RAM; boot with a single known-good DIMM in the primary slot. This narrows down peripheral/slot issues.
  • If comfortable opening the chassis, momentarily short the two pins of the power-switch header to rule out a faulty button (use an insulated probe, be cautious). If unsure, skip this and get a shop to help.
  • If the machine boots more reliably once warm, that strongly suggests dry solder/BGA cracks. Reflow can sometimes restore function temporarily, but it’s a risky, non-permanent fix; motherboard replacement is the long-term solution (as experienced).

Safety and next steps: observe ESD precautions and don’t attempt power-rail measurements unless you understand electronics. If the adapter and power-switch checks don’t find the fault, budget for board replacement or professional repair—both and ’s observations align with that outcome.

Recommended Answers

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Member Avatar for mechbas

As a primary source are you using batt. power or the AC adapt.?

Member Avatar for acarr

As a primary source are you using batt. power or the AC adapt.?

Either one it doesn't seem to matter. Sometimes it seems to help to plug it in, unplug it, take out the battery and put it back in quickly and it will start. But that doesn't work all of the time.

Member Avatar for mechbas

Switches get used a lot and consequently wear out quickly. Cleaning might help but I doubt that you'll be able to get into it that well. This one seems destined for the technicians bench.

Member Avatar for bugbite7

Hey Alan-

I had the exact same problem about a month ago... My computer was still under warranty, so I took it in to a toshiba center. They diagnosed the problem as having to do with the motherboard, and replaced it. The problem has been fixed since then. I know it's an expensive way to fix it, but I just wanted to let you know to help point you in the right direction.

You could also try to update the BIOS from the toshiba website to see if that helps...

Hi I have a Toshiba Portege M405 Laptop that is just over a year old and just out of warranty.

The problem is that about 90% of the time when I hit the button to turn it on all that happens is the power light comes and nothing happens. Other times the power light flashes yellow and the cpu fan comes on full speed. I then hold the power button to get it to turn off and have to try again.

This can happen dozens of times before it will actually boot. Once it actually does boot the computer works perfectly until I turn it off again. Then its any body's guess when I can get it to start again.

Things I have tried:

-I have removed the hard drive, it still wont boot at all even to the bios.
-I have tried removing the memory one stick at a time and have run memtest on it. Came up fine.
-Have disassembled it and looked for loose connections or cold solder joints, re seated everything. This didn't change anything.

Thanks for any help that you might have.
-Alan

Member Avatar for techno t

Sounds like a bad solder joint somewhere (probable one of the BGA's)

If it runs fine once warm and not when cold then this does strike as a dry joint somewhere on the board. This will either mean a replacement board or playing round with a heat gun on the mainboard yourself, although not always a way to get a fix

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