Blown motherboard!?

[DeathPrincess]

I need a third opinion, because the first two (mine and a toshiba repair place) vary wildly. Someone I know had a broken laptop (broken DC jack). And as I hate soldering and doing anything with a laptops (theres no laptop ATXtype standard thing) and I have long nails damnit. It was sent in and came back all shiny new.
For a week.
(a week) Later I was asked to look at it because of BSODing. It was a faulty RAM module. (this might be important). So I took out the 1gb stick and ran memory tests, and they all came back fine. When I finished up with the second memcheck on the single chip it switched off. I checked the light indicators and neither the power or battery icons were showing, even with the power plugged in. So I thought they must have left something unplugged inside. Dissasemble, check connections, nothing. Wont turn on, low battery signal flashes.
So as it has been a week since its been back, so I called the repair place. Apparently its not their fault. I phone toshiba who says it is. Toshiba phones them, they agree to do it under warranty. Send it back in.
But now according to them using a power supply with the wrong voltage (the one that came with it) has blown the motherboard. I dont remember seeing any blown caps. But it does look rather suspicious as everything else worked fine. But the motherboard costs 250$. Which is expensive for a motherboard without 4 x16 slots. and raid12. And if it was just due to overloading, wouldn't it just be a few capacitors, as the CPU, etc etc. all work. It sounds like their just being like those weird car mechanics. (your oils needs changing because the engines breaking the oil. So we're replace the engine instead)
I know it sounds plausible. But convince me im right and that they're fools. The laptop is a slightly old satelite a300 by toshiba

 

[BillParrish]

If I had long nails I would just scratch my eyes out everytime I was asked to work on a laptop to avoid the job.


So despite Toshiba telling them to "fix under warrantly " they want to charge you for the MB ?

This does not seem right. If under warranty its under warranty and the "you used wrong brick" is red herring.

If the DC jack was broken it means that a strain was put on the power cord from the brick to the machine. More than likely the plug/wires where strained. I suspect (as you allude to, I assume nobody used a wrong brick so it MUST be the original brick if the Brick is the cause) the original Brick was damaged with an intermittent connection in the plug wires right at the plug when the original damage/accident happened to break the jack.

So have they tested it with a known good Brick instead of the one I am guessing you sent back with the machine ?
If you have the Brick, set up test leads (probe and alligator clip) on the plug and move/flex the wires at the brick and the power plug end and watch for voltage going away due to internal broken wires or spikng above rated output etc.

Thats my best guess. The rest of it is a procedural issue that I dont know what you can do about other than to steadfastly maintain that "there is no other brick" and "blown" tells you nothing.

I think the brick is actually bad due to the overstrain on the plug incident and either the brick was not sent in for repair and has subsquently casued the problem or if it was sent in with the original repair no one tested it extensively (due to the damaged jack the possibity of an intermittent damaged wire in the brick occured to me but I am a wiley old bastid) and did not catch the intermittent problem. Tested ok, sent back, your user unfortunately move something just right and fissssist - blown board - whatever that really means.

So I put $2 on "Bad Brick" to place. The rest depends on if the Brick is found to be bad or not.and if the brick was sent back with the first repair or not. Once those questions are answered a rational argument can be constructed for who should pay for MB.







----- this is junk I was typing in a "thinking out loud mode" it is not to the point but might interest you - or not.



Just wth is a "blown" motherboard ? The brick power supply could be defective and providing too much voltage to the board. OK should all be covered under warranty.

I dont know about Toshiba power bricks but assuming they are like dell etc. they put out something like 20V DC and there should be other components on the motherboard or perhaps a little board in the laptop to convert that raw 20V into the other more stable +5, +12 etc. I would think that circuitry would be what should have "blown". Actually if designed worth a damn there should be a fuse or some other kind of overvoltage protection in that circuit but /shrug. I guess my point in that "blown" tells us little or nothing other than with an educated guess the power portion of the board has somehow been damaged. I guess it is possbile that the design was so crappy that a overvoltage or surge of some kind some how could have both fired the internal volage/power supply/regulation circuits and gone on to damage the logic (but note they did not mention a new CPU or memory) just a motherboard.

The more likely thing is that they checked the board and did find the voltage regulation circuitry fried and the cost of repair (2 additional hours of work and remember they already, maybe, if not outright lying, have had someone skilled look at it for 1/2 hour or so and then handling and tracking through the repair depot) it is just cheaper to replace it outright. Frankly if it is a new and not refurbished MB $250 for a laptop is not too bad. Of course the question is when does it become better to toss it and spend on a new one. Not quite sure from your post what your exposure is.

It sounds like it is out of main warranty ?

The broken DC jack could have shorted but I do not see how a short there could cause the onboard stuff to fail (all the current would go to ground right at the broken jack with laptop not getting power and jack starting to fry if the short allowed to continue. But stranger things have happened.

I am fairly certain that they are not quite sure exactly what is wrong with the board and it will take an appreciable amount of work to figure it out, retest etc. and the easiest way out is to sell you a reworked board that is in the spares depot and then they can take their time fixing that one, testing etc. and into the spares depot it goes for the next customer. That is typically how these places run, It is very inefficient to fix anything the least bit complicated on a customer to customer basis.

Did you send them the power brick with the laptop ?
Did they say they tested the brick and what the results where ?
If you have it can you check what the output should be and stick a multimeter on it for giggles ?


I dont buy completely the "blown" board but understand what they are really saying/doing.
The "power supply with wrong voltage" is red herring - unless you can get owner to admit it and usually most other bricks for stuff around the house are lower votage and should not have hurt anything if somehow the plug did end up fitting. And its their brick they should be responsible. So no, I am not buying that. Lightening surge maybe, other than that they are trying to shift blame.

 

[DeathPrincess]

Because of my loathing of laptop repairing, nothing much to play with etc. my total exposure to laptop motherboard have all happened in the last month. When they make standard parts then i'll be interested as I can build my own, upgrade etc.
The Warranty isn't the original warranty, but a 90 day warranty that they gave to the laptop after repairing it out of warranty. Which had about as much literature with it as that last sentance. So it's hard to argue points with it. Theywouldn't hold to it, so I got toshiba to get them to hold to it.
When it was sent it, they requested laptop only, I even asked if they wanted other parts, they said "no laptop only". I removed hardddrive because you always should and the courier collected it.
I'm doubting the power surge thoery, because the extension chords used (because the cable was short) both have surge protection circuits.
Also, the computer didn't shut off suddenly. It was just running on battery supply (fully functionally apart from the RAM chip but it's a quite old Hynix brand. I've never used that brand so I don't know about relaibility, I know they make server memory) which I was surprised that the next week after returning it broke) And then shut off when the battery ran flat. I was able to recharge the battery a little by the warming in the hands technique. (which im not sure even works on laptop batterys but it does on rechargable camera ones!) So if it was able to run off the battery, then wouldn't it mean that the motherboard itself was ok, and as you said something to do with the voltage contraptioness. But no, they didn't say that anything else needed replacing, luckily only the most expensive component, its almost as much as I paid for my P6X58D. It was originally a 500$ laptop as far as I know.
I'm pretty sure the brick was 15v-18v as far as I remember. And if something blew...wouldn't it take out at least on capacitor? Otherwise laptop motherboard "blow"ing is boring.
Ill try and get a meter from somewhere...as I currently don't have one!
Thanks!

 

[BillParrish]

Just an inexpensive DVM from about anywhere is handy. $15 or so. Find one that uses a "normal" battery, Usually the batteries last several years but no since getting one that will be a pita to replace when it does go. Mine uses a regular 9V.

Most caps are rated for at least 20% more voltage than they are expected to see in normal operation so it usually takes a pretty catastropic overvoltage to make them "pop". Were a diode would just instantly and quietly die with no outward signs if its reverse voltage was exceeded . So I guess the answer it if you find ruptured caps likely a lot more is also gone but if the caps look ok there is no telling, visually, what it could be. So we are back to wth exactly does "blown" mean . /shug.

Good luck.

 

[DeathPrincess]

"blown" is a good word! I think I "blow"ed a fan controller once. With a 18w pump and a scythe on the same channel just to make sure it was changing speed. But i'm sure the motherboard damage isn't that spectacular. I'm sure someone would have noticed the smoke, because it smells kind of nice.

Do you have any reccomendations for a decent DVM, as you can see i'm not the worlds best electrician, or are they all pretty generic brand wise? Apart from making sci-fi movies is there ever any reason for getting an osciloscope? Thank you for your help!