Weird Startup Problem With Toshiba Laptop - Genius Diagnostician Needed

[Rustys]

Keep us informed

[steverob]

I just swapped out the processor. It’s made no difference: it still won’t start.
So in summary:

• Refurbed mobo (and this means the BIOS is different as well)
• New battery
• swapped out SODIMMs
• refurbed CPU
• nothing out of the video port, and occasionally the screen springs into action as mentioned, so I don’t see how it can be the screen

All the main components changed and nothing has made any measurable difference.

[georgeks]

Have you tried one memory module at a time (try both on the 1st slot and then on the 2nd) ?
Are there any additional boards that you have to connect to the motherboard (e.g. USB ports)?
Do you get a signal on Video out if you disconnect the LCD?

[Bruce]

about the only thing ‘out of the box’ that may (just may) be left to blame is the LCD backlight.
once gone, I’ve never seen one come back to life - but maybe lose wire, lose connection… who knows.

when it does work (the screen that is) and it shows either the BIOS info or the Windows splash screen, those locations where you know there should be text - when it doesn’t show signal, can you really squint at those spots and see any wording? signing a torch onto the screen can help.

I’m just wondering if the text is there but due to the backlight not working, it’s just really hard to see.

long shot I know but otherwise I’m tapped out.

what was the end result of swapping the HDD - any luck?
and did you try removing the drive and memory and booting - you should at least get “no boot drive” or “no memory” errors on the screen and be able to get into BIOS.

[steverob]

More developments:
a) Swapped out memory modules - no change
b) changed the HDD - it booted once. Then on reboot it displayed the same symptoms - nothing. No amount of Fn f5 and shift f8 reboot sequencing would help.

I wondered if the issue is that there’s been an unknown accident to the keyboard and it’s booting with one or more keys"activated" due to some liquid being poured over the keyboard in the past (it belonged to my daughter - nothing is impossible.) That said, there’s no evidence of liquid damage, although plenty of crumbs. So I removed the keyboard. 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.

I noticed that at switch-on the CDROM activates - not sure whether this is a normal part of the pre-boot routine, so I removed the CD-ROM drive. Again, it booted, but refused to boot a second time after switching off.
When I’ve been able to get something going, I’ve entered BIOS and examined the settings: everything is as it should be. I changed the order of boot devices - makes no difference.

So all in all, in summary, when there’s a hardware change, there seems to be a higher probability of booting. The screen is definitely OK and no faint characters observable with a flashlight with a blacks screen. And no signal from the VGA port.

[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 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]

[ATTACH type=“full”]7506[/ATTACH]
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: