Weird Startup Problem With Toshiba Laptop - Genius Diagnostician Needed

[Rustys]

It booted, but I couldn't go any further because of there being no keyboard (but will try with a USB keyboard later). On reboot, the same black screen. No amount of switching on and off changes anything.

This is a bit confusing you have or have not used the USB keyboard.

DVD starting during boot is normal the BIOS will run a POST and test the hardware in the system.

 

[steverob]

Ah OK - no, I didn't use a USB keyboard. After I wrote that post, I removed the laptop keyboard and plugged in a USB keyboard but couldn't get anything to happen. At the moment, no matter what I do, the power light lights up, but absolutely nothing else happens. I can force a restart, and have tried the <shift> f8 power combination, and also fn-f5-power keypress combo - but it's refusing to cooperate. I didn't mention this, and perhaps it's significant, but in every case when I was able to get to a boot screen (mentioned above), I had also used one or other of these start protocols. I don't know what these key combinations do, but perhaps there is a clue as to what may be going on.

 

[Bruce]

while on one hand I commend you on your perseverance, I think you have done all that is humanly possible to resurrect that unit.
but on the other hand - it would be great to find out why....

 

[Rustys]

I have to agree with @Bruce we have replaced and tested pretty much everything from what I have been reading.

Have you attempted the USB live Linux yet?

 

[steverob]

Interesting.
I inserted a bootable CloudReady USB key (Chromium OS) and tried booting after leaving it overnight. It booted to this screen.
I clicked f1 to resume and it booted the HDD (which was higher up the boot order) as it should.
Then closing down and starting up again, it went straight to the black screen. At the moment I can't get it to boot, but this supports the observation that booting seems more likely when there is a hardware configuration change.

Does the startup screen reveal anything?
I think I'll disconnect the USB daughter board and see if that does anything. Also the wireless LAN card

 

[veeg]

Any updates?

 

[steverob]

After a few days of finding something more rewarding to do, I took the unit to bits again, then reassembled, leaving the USB daughter board, speaker and mic connectors uncoupled, and I also removed the Wifi card and disconnected the CDROM drive. The unit booted fine. Then after switching off and rebooting, the same problem - black screen. I'm of the opinion that making hardware changes is having some effect but it's not repeatable in any consistent way. There are hundreds of Google results for "Toshiba laptop black screen" but I have yet to find anything that explains and remedies this strange behavior. In EVERY case when I have successfully booted the PC, the reboot always fails. And the fail happens quickly on startup - as if it's something to do with POST.

 

[Bruce]

I wonder if it's a cold boot thing.
like the time you take to make those hardware changes is enough time for the capacitors to completely drain and the 'first' time after those changes - it boots.
but the next boot is a warm boot - there's still residual charge in the system.

try turning it off, pull out the power cord and remove the battery then turn it on, you may see some LED's briefly flicker and fans spin. that'll drain the system.
then reconnect the power (leabe out the battery) and boot as normal.

long shot but hey, that's where we are up too!

 

[steverob]

I agree that your analysis makes sense, but booting after the power button has been depressed for a minute with all power sources removed (then added back) doesn't produce any change in behavior. Power light goes on, a short burst of a dsik spinning all in the first second or so and then silence and a black screen.
The end of the tether is nigh.

 

[Bruce]

bugger :notworthy:

 

[veeg]

Any updates?

 

[phillpower2]

Thread closed due to lack of any feedback from the OP.