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.
Laptop parts | Repair Man | 
December 26, 2008 3:45 pm
299 Responses to “System board also know as motherboard”
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Pages: « 12 … 11 10 9 8 7 6 5 4 3 2 [1] Show All
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
January 13th, 2009 at 2:39 pm
Mary,
Yep, your description sounds like a problem with the motherboard. Just in case, you might need this service manual for Dell Inspiron 8500/8600 laptops. It explains how to remove and replace the motherboard.
Your laptop doesn’t start, so you cannot run any test at all.
You can do visual inspection. For that you’ll have to remove the motherboard and take a closer look at both side, searching for burn marks, blown capacitors, etc…
Here’s something else you can try. Start taking your laptop apart piece by piece and test it after each removed component:
1. Remove the hard drive and test the laptop.
2. Remove the DVD drive and test the laptop.
3. Remove the wireless card and test the laptop.
4. Unplug the display panel from the motherboard/video card and test the laptop.
etc….
Continue taking it apart until you have only three major components connected: motherboard (with video card), processor, and memory. If you still experience the same problem, most likely it’s bad motherboard.
By the way, before you start, try reconnecting the memory module. If you have two modules installed, try removing them one by one and test the laptop with each one separately. I doubt it will help, but try it just in case.
January 13th, 2009 at 2:09 pm
Lili Adams,
I don’t think that you killed the motherboard. It’s very likely that your laptop will not start because one of the memory modules (or both modules) popped up from the slot.
If there is bad connection between the memory module and motherboard, the laptop will not start.
I would suggest tacking a closer look at the memory modules. Try reconnecting them just in case, it might help.
This service manual for a Dell XPS M1330 laptop will be handy if you don’t know how to access and reconnect memory.
January 13th, 2009 at 6:33 am
I have a Dell Inspiron 8600. I shut the lid half way down (I don’t think it went far enough to hit the hibernation switch) and it shut off. When I press the power button the LED’s come on for about 5 seconds then shut off. No fans start. Nothing except for a high pitched whine (very faint). I removed the battery for about 5 minutes and tested the ac adapter with a volt meter. Everything checked out fine. Still nothing. I tried it with the battery and no adapter, still nothing.
I Googled my symptoms and it points to the motherboard. If it’s the motherboard, is there something that I can check and replace on it. I didn’t want to buy a motherboard and not have that be the problem.
Thanks so much for any help.
January 12th, 2009 at 10:55 pm
I have a Dell XPS M1330. It’s a new laptop and it worked great until I accidentally dropped it from my bed. After that it stopped working. When I turn it on, the laptop starts but nothing appears on the screen. Did I kill the motherboard? What could be wrong with my laptop? Do I have to pay for repair?
January 9th, 2009 at 10:00 pm
cp,
Your data is saved on the hard drive. You don’t have to reinstall the operating system after motherboard replacement.
January 9th, 2009 at 8:49 am
Is it necessary to reinstall everythign after mainboard replacement? Will I loose all my pictures and music?
January 6th, 2009 at 1:26 pm
Rob,
You’ll find motherboard removal and fan replacement instructions in the service manual for Dell Inspiron 1525/1526 laptops.
Dell instructions are very clear. I guess you can do it yourself if you are careful enough.
January 6th, 2009 at 12:55 pm
Need help with a Dell Inspiron 1525 notebook. The fan died. Cannot remove from the bottom. Is it on the motherboard? Can I remove motherboard myself?
January 5th, 2009 at 1:47 pm
Handle motherboard carefully, it’s static sensetive. Wear wrist strap and do not touch components.
Statick electricity can kill motherboard!!!
January 3rd, 2009 at 9:51 pm
chika,
Open the memory compartment door on the bottom of the laptop and remove memory modules. There should be a sticker with the part number. Your part number will look something like that: K000007530. One letter followed by nine digits. Your letter and digits will be different and I used this part number just as an example.
Find the part number and google it. Most likely your search will bring you many places where you can buy a new motherboard for your laptop.
January 3rd, 2009 at 3:14 pm
I took my laptop to a repair shop and they said the mobo is fried. I can swap the mobo myself buy where and how I can find a new one? It’s a Toshiba laptop.
Tnanks
January 2nd, 2009 at 9:56 am
Mido,
1. It’s possible the AC adapter died while you were working on the laptop. The laptop was running until you had charge in the battery and after that it turned off. Can you test the AC adapter? Make sure it outputs correct voltage.
2. It’s possible that you have bad RAM module. Do you know if you have two RAM modules installed in your laptop? Try removing them one by one. If one of the modules is bad, the laptop should start when your remove it.
January 2nd, 2009 at 9:50 am
My laptop is Valiant6370iPT manufactured by KDS Computers. While I was using it, it suddenly turned off and I haven’t been able to get it started again since. The only activity is the Num/Scroll/Capslock LEDs flash once and then the laptop remains dead. No fans, no video output, nothing. I suspect the motherboard is simply fried.
December 30th, 2008 at 8:08 am
Lee,
Most likely the wine went down to the mothreboard and damaged it. It’s necessary to disassemble the laptop and take a closer look at the motherboard. If you see corrosion, you’ll have to replace the board.
December 30th, 2008 at 12:04 am
Spilled a glas of wine on the keyboard and my laptop died. No lights at all. I removed battery, turned it upside down and let dry out for 3 days. Still same problem. It’s totally dead.
December 28th, 2008 at 2:00 am
Nope, it’s not the jack. I removed the motherboard and tested voltage on the jack. I’m pretty sure that power goes to the motherboard. The fuse looks good too.
I guess I was right, the motherboard is fried.
Thanks.
December 27th, 2008 at 2:55 pm
JustAGuy,
I cannot tell without looking at the laptop. I think it could be one of the following:
1. Bad/damaged power jack and because of that the power from the power adapter doesn’t go to the motherboard and it appears to be dead.
2. Bad motherboard.
December 27th, 2008 at 2:43 pm
I think my mobo is fried buy I’m not sure.
The laptop is dead, it has no lights even with new adapter. Do you think it’s fried mobo?
December 27th, 2008 at 11:40 am
Neil,
The best way to find a new motherboard for your laptop would be searching by motherboard part number. In Dell laptops this part number is usually located in the memory compartment. If you remove one of the memory modules, you should see a white sticker with a long string of numbers.
For example, here’s a string from a Dell laptop: CN-0UK434-48643-84F-2286
The second set of numbers 0UK434 is the motherboard part number.
You can find a new motherboard if you Google the part number.
December 27th, 2008 at 11:24 am
Hi,
I have a Dell Inspiron 1720 with bad motherboard. I know how to replace the motherboard, I found instructions. But I don’t know where I can buy a new motherboard. How can I find a new motherboard for my Dell?