Dead Toshiba L50

[mrapoc]

Posting on behalf of Chris who works with me at Fresh PCs (he doesn't quite have enough post count yet)

I have a Toshiba Satellite L50-B-1N8 that when plugged in illuminates all the lights straight away, without pressing the power button, including NUM & CAPS lock.


The screen is off and the fan spins up for 5 seconds then goes off and stays off.


The only part of the board that warms up slowly is the CPU area. There are no hotspots that indicate a short circuit and I have done resistance checks to some of the main components to see if there is a dead short to GND.


I have put the DVM across some of the main components, such as regulators and they seen to have reasonable voltages on them. There is 19V coming in onto the PCB from the DC jack, 4 pins: 2 GND and 2 19V, one of the two 19V has 0V on though.


I am hoping someone might have access to the schematics or have a good idea of what problem might be based on these symptoms. Leading up to this the laptop was in for a keyboard problem, R and 1 keys were very intermittent.


I have tried all the usual, such as barebones, power drain, hooked up to external display, re-seated & tried different RAM and used compressed air to blow any potential F.O.D. out of all the hiding places.


Thanks

All I know from what he said is that it was working ok when it came in apart from the keyboard was acting sketchy - changed the keyboard and it was working (in bits). Put it all together and then it started acting up. I've had minimal contact on this job apart from stripping down (the laptop) and the usual power drain. He did perform a bios update at some point but I can't see that going wrong else he would have known about it.

 

[nlinecomputers]

So how does it run on battery?

 

[mrapoc]

I think fan comes on but nobody home. Same as described - comes on without the power button needing to be pressed. I would have called it by now but obviously its an awkward situation:

It came in working as such.
What caused it to die.
Chris also wants to fix it.

 

[nlinecomputers]

Southbridge chip was probably already bad hence the keyboard issues and died on the bench. Replace the motherboard.

 

[HCHTech]

That sucks, man. There's probably no way to convince the customer you didn't break it (and you did, since it happened on your watch). Probably should just eat the cost of a motherboard and hope this is your one unavoidable problem for the year. You've got 6 months left, karma should balance it out by then.

 

[mr m]

Some L50's have a force shutdown switch that can be accessed through a small hole on the bottom of the unit. Worth a shot.

 

[Larry Sabo]

Sounds like a borked BIOS. If it were mine, I'd find a place that can re-program the BIOS (or do it myself if my EEPROM program can handle that BIOS).

 

[TurricanII]

Is it out of warranty? Probably is but good to check, just in case it has any extended warranty.

I don't do much with laptops but had an odd problem with a Yoga 2 13" Lenovo; it would power on for a few seconds and then go off. I had only taken the bottom cover off. I had to full assemble it to make it work again. I thought it could be a magnet/switch problem with the mechanism that told the laptop it was closed. I would check whatever mechanism is telling the Tosh whether it is open or closed.

 

[Computer Bloke]

It's interesting that you said it was working when it was in bits and that when reassembled it consistently switches itself on when power is applied and then off again five seconds later. This is exactly the kind of behaviour you'd get if the power switch were to be permanently depressed.

Could it be that when the machine was put back together the power switch was jammed down?

 

[HCHTech]

This is exactly the kind of behaviour you'd get if the power switch were to be permanently depressed.

I like this. It fits the fact pattern and follows Occam's razor. +1

 

[glennd]

It's interesting that you said it was working when it was in bits and that when reassembled it consistently switches itself on when power is applied and then off again five seconds later. This is exactly the kind of behaviour you'd get if the power switch were to be permanently depressed.

Could it be that when the machine was put back together the power switch was jammed down?

I'll put money on this one...

 

[mrapoc]

I'll ask him to check. I think when I had a play I tried it without the power button daughter board and is still powered on with no display. I'll also see if he can retry recovering bios. I still think the southbridge or something was faulty but hey ho.

 

[mrapoc]

Ok so I have had a look at it - with the power board detached it still powers on without pressing the power on. Trying all manner of bios recovery key combos and bios files on fat formatted usb sticks does nothing. Checked out the usual capacitors and it seems ok.

No video output and caps lock/num lock are lit up. Can get the usb stick to flash twice if we hold down the power button. Nothing if we don't.

Now I've been sucked into it

 

[nlinecomputers]

Now I've been sucked into it

Don't. You already are likely to have to buy a new mobo for this. It's dead. Order a new motherboard ASAP. Time is money and this is already a busted job. Time for damage control not puzzles.