I have a Toshiba A100 laptop which is faulty.Symptoms are: dead,no indicator lights.Have been able to substitute battery with a known good one-fully charged.Have checked both mini-fuses on power supply input in motherboard.Suspect problems in the power supply section of motherboard.Are circuit diagrams available for these ?. I downloaded maintenance manual from internet but this only goes to board level-not component.Any ideas anyone ?
In order to replace the power jack in your laptop you’ll have to remove the jack from the motherboard as I explained in the previous post: Replacing DC power jack.
While removing the jack you can accidentally pull out the internal copper coating (I’ll call it a sleeve) from the inside of the “+” terminal as it shown on the picture below.
The internal copper sleeve has been removed and cannot be installed back. If you solder the power jack back on the motherboard without this sleeve it might work but the connection between the “+” lead and motherboard will not be reliable.
In the following guide I explain how to fortify a damaged power jack connection. You can use this repair technique in some laptops with similar power jacks.
Laptop is dead. How to troubleshoot the problem.In this post I’ll explain how to troubleshoot a dead laptop and find the problem. The following troubleshooting tips are not model and brand specific, they should work for most laptops.
Let’s take a look at two different scenarios.
Example 1. The laptop is absolutely dead.
When you plug in the power adapter and press on the power button, there is no signs of life at all. The laptop will not make usual noises, LEDs will not light up, the fan will not spin, the screen is blank and black, etc… In short, the laptop is dead.
What you can do in this case?
1. Make sure the wall outlet is working and the laptop DC adapter is getting power from the outlet. Try another wall outlet.
2. Test the laptop DC power adapter, make sure the voltage output is correct. You can test the DC power adapter with a voltmeter.
3. Let’s say the DC adapter is fine and the adapter outputs correct voltage. In this case unplug the power adapter from the laptop, remove the battery, wait for 1-2 minutes, plug in the adapter and try turning on the laptop again.
OK, you tested the adapter and it’s bad. If you decide to replace the original DC adapter with a generic one, you’ll have to follow this rule:
The voltage output on your new adapter has to be exactly the same as on the original adapter. The amperage on the new adapter could be the same or higher.
If nothing helps and the laptop is still dead, apparently the motherboard is fried or there is a problem with the DC power jack. It’s possible the DC power jack is broken and the motherboard is not getting any power from the adapter. In this case you’ll have to disassemble the laptop and replace the power jack. Check out thisguide for fixing laptop power jack.
The diagrams can be asked from service of toshiba
I honestly don't feel that you can repair a laptop motherboard at component level, atleast that is something I have not attempted.
We replace motherboards we mainly don't attempt to repair them at component level, how about you send the motherboard to repairflow service if available or get a replacement.
thats just my opinion.
Hi,
Seems the motherboard is dead.
If I were you, I would go ahead and get a used/ faulty laptop with working motherboard
or
get a salvaged motherboard online from ebay.
It should be cheaper.
In india call 09924444848 or there i many chip lavel reapairs avalavble when u live just send me yr plase name or address i give u a address..:)
Hi Mike,
Do you know why factories do not provide component level detailed schematics, and troubleshooting diagrams to test Motherboard's component on a laptop?
Because the motherboards are considered not serviceable from factory.
When you do a laptop repair course ( I did Compaq a long time ago, before it was HP), they teach you that you can test only simple components, and look easily idetificable faults, and that is not worth testing ICs on such units, as the job for replacement and teh high risk the job is not at factory standard make this kind of repairs not worth.
Try spotting bulged capacitors, bad solder joints, parts shorting to chassis, and test all resistors and components that you can test.
The problem is not necessarily near to DC adapter socket (that area of board is not called PSU on a MB), as suggested test the connector, and the resistors near to DC connector, they are common fault when you get no power at all.
Parts like the video chipset and many more chips can be tested, but diagrams are not provided on service manual. Therefore you need to download the single tech sheets , that is a hell of a job
Here you find the service manual on 19 parts.
Download all 19 parts and unzip first one with winrar, the other ones will be added automatically.
Regards.
HI Has it been overloaded? Is the power strip turned on / is the outlet working? Is the cord from the adapter to the wall fully plugged in on both ends (try wiggling)? Your adapter may be fried- try borrowing an indentical adapter from a friend and seeing if that one will work in it's place (but do not plug it in to your computer, or you might fry your friend's adapter).
HiÂ
 track it down to transistor u45 .Transistor pulls down startup supply regulated by u26 3.3V regulator.Output is on pin3.
U26 sits underneath just behindVGA socket and U 45 is 70mm north U26.
Replace and problem solved.GET A new transistor from a
scrapped motherboard.
good luck
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talked about this before : when i decided to have a mini35 adapter i chose nikon lenses. a 50mm 1,4 and a 28mm 2,8 to be precise.
i also have a really nice TOKINA ATX 35-200mm f/3,5-4,5 but it's a canon FD mount.... my brain start to work (for the first time ever) and i had this idea :Â
the focal flange of the canon fd is shorter than the nikon, so i just have to build an adapter to reduce the focal flange ... yeah that's stupid but i was persuaded that playing with the rings will allow me to reach a solution.
and this is what i've done :
1. put away my nikon 50mm + the nikon to canon eos adapter
2. put away the bayonet ring
3. put the canon fd mount with the adapter i've made.
4/5. the adapter is made of a rear canon FD lens cap(i made the hole) and a macro extension tube number 1 ( i had one left) and sort of glue the two (the screws are a temporary solution)
6. i screw the adapter on the canon FD lens.
7. this how it looks. this is really rigid.Â
SEE TESE
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Refer to the link :)
http://www.laptoprepair101.com/
Thanks.
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scrapped motherboard.
SEE TESE
I dont know the answer to whether its a dual core or not.The fuses were checked with an ohm meter.They are surface mount types.
Hi Robert
I beg to differ with you regarding measuring fuses in circuit.To read O ohms across it is a pretty good indication that the fuse is ok.
I had earlier tried unit with just the power pack without the battery.
Unit is dead in all modes.
I am a professional electronics technician with 35 yrs experience but my abilities with laptops is somewhat limited.
Cheers
Mike
Is there anyone out there who already has a circuit of the power supply section of this laptop who could email me a copy.?
Just to clarify a couple of things here, both
battery and power packs are ok as 14 volts or so can be measured on power supply side of both
s.m. fuses.I suspect motherboard/system board problems here but because the symptoms are so basic ie-dead, the cause may be one of the small ic's in the front end of the power supply which could fairly easily be replaced if circuit info was available-thus my query.But another possibility could be a crook CPU. Does anyone know if this can cause "dead symptoms" if this is faulty ?
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