System board also know as motherboard
A system board also known as motherboard or mainboard is the main circtuit board in any laptop. Unlike desktop PC system boards, laptop system boards come in thousands of different shapes and sizes. Laptop motherboards are model-specific. In other words, you cannot remove motherboard from a Toshiba laptop and stick it into a Dell laptop. All parts inside a laptop are connected to the system board, either directly via a connector mounted on the system board or through a cable.
In a typical laptop the following ports and components are permanently attached to the system board and cannot be easily removed and replaced without soldering:
1. Hard drive (HDD) connector.
2. CD/DVD drive connector.
3. Memory (RAM) slots.
4. Battery connector.
5. Keyboard connector.
6. Audio (headphone and microphone) jacks.
7. Volume control wheel.
8. USB ports.
9. Eithernet (RJ45 aka network) port.
10. IEEE 1394 (Fire Wire) ports.
11. Video chip and some other components and ports.
System board, processor (CPU) and LCD screen are the most expensive parts in any laptop. In some cases, when one of these three parts fails, it’s cheaper to buy a brand new laptop than replace the failed part. But each case is different so do your research.
The system board is mounted inside the laptop base assembly. In order to remove or replace the motherboard, you’ll have to disassemble the whole laptop.
SYSTEM BOARD FAILURE SYMPTOMS.
When a system board fails, you may experience the following most common problems with your laptop. 1. The laptop is completely dead. There are no LED light activity when you press on the power button or plug in a known good AC power adapter. 2. The laptop starts but the video output on the LCD screen or external monitor is garbled. Most likely this is related to the VGA chip failure. 3. The laptop turns on without video on the screen and the power LED starts flashing. 4. The laptop works fine with AC power adapter but will not charge a known good battery. If that’s the case, most likely there is something wrong with the battery charging circuit or DC power jack.
Need spare parts for your laptop?
If you are looking for spare parts for your laptop you can find brand new and used parts here. Just search by the part name and laptop model.
February 8th, 2009 at 7:11 am
I’ve tried it before. The screen will also go blank while doing so. It doesn’t shut down, the CPU fan is still working.
But on 2nd retry it seemed to be ok. I was using the laptop this morning and while the CPU is processing something, the screen again goes blank. But the CPU still appears to be processing something as the LED still lights up. And it just stays there, no shut down, nothing, even the CPU Fan is still working in there.
I shall start to backup my data tomorrow morning as I think I might drop it off to a nearby computer store sooner rather than later. And I still desperately hope that it is the RAM that is giving problems.
February 7th, 2009 at 9:17 am
Stan,
Try running memory test when the laptop works. Boot from the Memtest86+ and let the test run overnight. If you get memory errors, try replacing the RAM module.
February 7th, 2009 at 8:06 am
Repair Man,
Thanks alot for your advice. The most “mysterious” thing is that it doesnt happen all the time consistently. Sometimes it’ll work fine for a few days before the problem occurs again. When it occurs, after awhile, or after some knocking here and there abit, it appears to be working just fine again. (and the cycle continues).
I’ll look at it for maybe a week more. If problem re-occurs, maybe I should send in for repair by an actual technician as I’m not certainly not at that level yet. Anyway, thanks alot for your advice.
February 6th, 2009 at 11:54 am
Stan,
I would definitely try replacing the RAM module first, it’s way cheaper than replacing the motherboard. I think that could be just a bad RAM module.
February 6th, 2009 at 1:18 am
Update: Now it wont even turn off. When the screen goes blank, the CPU fan appears to be still working and the power LED still on. And after 10 minutes, it still never shuts down. On 3 occasions, it didnt even made it pass POST. Motherboard failure or just RAM failure? Btw, how much would it cost to change the motherboard?
February 6th, 2009 at 12:28 am
Checked several times already, I’m able to connect to an external monitor, but the problem occured again. This time, when the problem occur, both the laptop LCD n the external monitor goes blank. Does this mean a motherboard failure?
February 3rd, 2009 at 10:42 pm
Stan,
In order to narrow down the problem you’ll have to test your laptop with a desktop monitor connected to the laptop. Check out the external video. Does it work with an external monitor?
February 3rd, 2009 at 9:06 pm
Hi. I’m having a problem with my 2 years old Compal laptop. The screen will suddenly go blank and then a few moments later, it appeared to have been powered off completely. It couldn’t be over-heating problem as I’ve just cleaned the fan and the ventilation hole. It’s not the power supply either.
Could it be my RAM or motherboard? I only have 1 RAM chip installed. I need advice from you guys desperately. Hopefully it’s not my motherboard that’s giving problem… It would cost alot to replace a motherboard..
February 2nd, 2009 at 3:58 pm
f-temp,
I wouldn’t do that. I would recommend installing the same motherboard as the original one.
The best way to find a replacement motherboard would be searching by the Toshiba part number from the old motherboard. In most cases you’ll find the part number on a sticker in the memory compartment. It will look something like that: K000039490, K000038660, K000037080 or another number but with same pattern – one letter and nine digits. Also, sometimes Toshiba might use a different number which looks like this one: 46139551L05 or something like that.
First, make sure that’s exactly what you are looking for. What if you buy something you don’t need? If you can find the Toshiba part number, you can google it and find more results.
I can if you can give me the laptop model number because there are different M105 laptops using different motherboards. Give me the number and I’ll look up the motherboard part number. After that you can search by the part number.
February 2nd, 2009 at 3:39 pm
Hello all,
My Toshiba Satellite M105-S3041 motherboard failed. Is it possible to install a toshiba motherboard for a different model? or does it have to be the exact same model?
I am trying to lookup a price but i am having a really hardtime and i am not sure how to search. By searching for Toshiba Satellite M105-S3041 motherboard on ebay i dont get any results.
What do you think the best course of action would be? accept a $100 offer for it?
Can anyone help?
January 31st, 2009 at 11:14 pm
Danny,
Did you test the AC adapter? Does it output correct voltage? Other than that, it sounds like a problem with the motherboard.
January 31st, 2009 at 7:47 pm
My HP ZE4900 laptop will not come on. The led for the battery comes on when its plugged into the charger, but when I press the power on button the power led will come on and go off. I have tried taking everything out one by one to figure something out but I am not having any luck. Any ideas?
January 25th, 2009 at 10:09 pm
Danny,
First of all, try this. Turn off the laptop, unplug the AC adapter and remove the battery. Now wait for a few minutes, then connect the AC adapter and try turning it on. Sometimes it helps.
By the way, how did you check the RAM? Did you try replacing the memory module with a new known good one? Did you try installing the memory module into the the empty slot, if you have any of course? Your description sounds like a memory related problem.
Try removing hard drive, DVD drive, other modules you can access and starting the laptop without them.
If still no luck, there could be a problem with the motherboard.
January 25th, 2009 at 7:27 pm
My laptop does on but did not start. A few component like fans and LED light work like usual. But no screen image appears and no response. System does not boot at all. Checking RAM found no problem. What is my problem?
January 25th, 2009 at 10:40 am
kamel,
I installed many different DOA motherboards into laptops with good working CPUs and it never happened to me. Maybe I was lucky.
As I mentioned in the comment 24, I’ve seen a very few failed CPUs so far. I guess it’s possible that installing a bad CPU can damage the motherboard, it just haven’t happened to me yet.
January 25th, 2009 at 2:16 am
Well I did see one case where trying 378 pin CPUs on a bad desktop motherboard burned the CPUs and an other case where trying a bad 478 pin CPU burned a good motherboard.
January 14th, 2009 at 9:47 pm
Gkrev,
Probably you’ve done it already but have you tried reseating memory modules? If you have two modules installed, you can try removing them one by one and start the laptop with each one separately.
You’ll have to guess but from my experience motherboards fail more often. I’ve been working with laptops for over four years now and so far I’ve replaced only three or four failed CPUs but I’ve replaced hundreds (if not thousands) failed motherboards. If you have to guess, I would try the motherboard first.
I don’t think so. As I mentioned above, I’ve seen only a few failed CPUs. I think in the worst case scenario the laptop simply will not boot.
Nope, I installed many good working CPUs into DOA motherboard and never had a problem. You just cannot start the system until you replace the motherboard.
January 14th, 2009 at 5:10 pm
I’m working with an HP 5100CTO laptop with an AMD Turion 40 CPU. Which belonged to my son. He’d been having trouble with what seemed to be heat-related shutdowns which he alleviated by throttling back the CPU speed. Then it shut down completely. All it does is turn on the power LED. No boot, no fans, no drives, no display. I’ve tried everything suggested so far. Now I’m thinking of replacing the CPU and/or system board and wondering which I should try first. Will installing a bad CPU in a new system board blow the board? Will installing a new CPU in a bad system board blow the CPU?
January 14th, 2009 at 3:34 pm
Mary,
After you unplug the display cable from the motherboard, you can test the laptop with an external monitor attached to the VGA port. Normally, the external monitor should be detected automatically.
January 14th, 2009 at 3:25 pm
Thanks Repair Man,
I will take it a part at work tomorrow (I’m an electronic assembler)and let you know if I find anything. I like the advice about trying the laptop after I remove each part.
Mary