Samsung NP300E5C MB problem

[frenchscottie]

I got the aforementioned laptop in for repair- wasn't turning on.
Turned out it was a burnt out component - could be a power resister.
The MB number was BA92-10501B so I ordered one from ebay, the company gets them refurbished from Samsung.
MB arrives I install and nothing, power light comes on fan spins for a second then stops, processor is hot. No output to screen or ext. monitor.
Changed the ram, have not connected hard disk and removed the bios battery.
Disconnected keyboard.
Sent it back and got a replacement, still the same.
So what to try next. The processor wouldn't cause a component to blow or vice a versa, would it?
Anyone any suggestions?
I won't be able to try any suggestions as I'm off on holiday for 2 weeks, but please leave them.
Mo

 

[scott_p]

Laptops are tricky, I have seen faulty touch-pads keep devices from booting past the POST.
From experiences parts off e-bay are almost always the problem but in this case I would say you have a dead processor.

 

[NYJimbo]

Turned out it was a burnt out component - could be a power resister.

"Could be" isn't good enough, if you know exactly what the chip was and where it was on the motherboard, you can often tell if replacing the motherboard is worth it. Sometimes a burnt chip is just the smoking gun of a bigger problem.

 

[Markverhyden]

Like a bad power supply. No mention if that was thoroughly checked.

 

[frenchscottie]

"Could be" isn't good enough, if you know exactly what the chip was and where it was on the motherboard, you can often tell if replacing the motherboard is worth it.

I'm sorry that my observation wasn't good enough for you, but it isn't a "chip" it is either a resistor or capacitor I think It has 2 connections but as it's burnt out I can't tell. And where it is on the MB isn't always a clue.
[/QUOTE]Sometimes a burnt chip is just the smoking gun of a bigger problem.[/QUOTE]
Exactly, that's why I got a replacement MB.

 

[frenchscottie]

Like a bad power supply. No mention if that was thoroughly checked.

Yes I checked the power adapter - always the first thing I do so just forgot to say.

 

[frenchscottie]

Laptops are tricky, I have seen faulty touch-pads keep devices from booting past the POST.
From experiences parts off e-bay are almost always the problem but in this case I would say you have a dead processor.

I've tried disconnected touchpad too.
Don't have problem getting Mb's from ebay shops, as in UK they seem to be our only choice as there are not many other places to get the parts unless you want to send the laptop to a Samsung etc. repair centre.
I've never had a dead processor before, but it I suppose it could be.

 

[NYJimbo]

I'm sorry that my observation wasn't good enough for you, but it isn't a "chip" it is either a resistor or capacitor I think It has 2 connections but as it's burnt out I can't tell. And where it is on the MB isn't always a clue.

Sometimes a burnt chip is just the smoking gun of a bigger problem.

Exactly, that's why I got a replacement MB.[/QUOTE]


You didn't even know what the part was but you tell me I shouldn't call it a chip? Well, I can tell you are really on your way to fixing this, good luck.

 

[frenchscottie]

Exactly, that's why I got a replacement MB.

You didn't even know what the part was but you tell me I shouldn't call it a chip? Well, I can tell you are really on your way to fixing this, good luck. [/QUOTE]

As I said the part has only two terminals so it isn't a "chip", well not in the UK anyway.
So how would you tell what it was?
I'm not an electronic engineer, but I do know a bit about electronics.
The part was burnt beyond recognition and has probably blown some of the tiny caps and resisters around it also.
If the board is damaged like this I replace it, and I've been doing it for years without a problem.
So what would you of done?
Your reply, although I appreciat you took the time, doesn't help in any way.

 

[PcTek9]

The Tell-Tell Part...

Well... There are a few ways to tell what the part was that burnt. You can sometimes see schematic symbols drawn on the pcb. -| (- is the symbol for a capacitor and also -||- a resistor symbol is -/\/\/\- like that. There may also be notational writing such as c54 indicating capacitor 54, or R382 indicating resistor 382.
If these are discrete components, then resistors are usually colored banded components, the colors indicating the ohms of the resistor. The standard colors are black, brown, red, orange, yellow, green, blue, purple, gray, white, silver, gold. Where silver & gold indicate tolerance values, and the other color bands indicate numbers or multiplier values.
There are other types of resistors, such as ceramic which are stamped, but they are power resistors, not often used on motherboards (if ever).
Capacitors come in many flavors. Electrolytic, mylar, ceramic, and more. Electrolytic looks like little cans sometimes wrapped in blue, black, tan, or another color of plastic with the values on the side.
Example 16v 3200 uF, indicating the voltage and microfarad values. Capacitors that look green chicklets are usually mylar or ceramic, and then the old orange and yellow and tan flat disks are ceramic as well. More often these tiny disk capacitors are usually picoFarad devices.
Can a bad cpu damage a motherboard? absolutely. Just to be extra super sure, I would verify this cpu actually is designated for the motherboard you are ordering. Also search the board for ways to identify dead cpu's in the future. Cpu's are low enough in price now that they no longer necessitate the use of logic probes, logic analyzers, and the like to verify pulse train traffic and so on. Besides... with Vlsi and beyond it's much to confusing these days for a text to even begin to analyze the output.
*Oh, and of course you could look at photos of the mb on the net and identify the component that way (as it is not burnt yet). Also check the battery pack to make sure it's not shorted out completely, and just burning up the power / charging regulation components. Hmmm, finally check that the adaptor supplied to you by the customer is actually the right voltage for that laptop. Customers sometimes make mistakes.
Good luck to you sir.

 

[frenchscottie]

Thanks PCTek, I knew all that anyway.
I don't even contemplate on repairing a Mb as the blown part probably isn't the only damaged/faulty chip or the cause of the fault is still on the MB and it could happen again soon after the repair. I always quote for the MB replacement.
I ordered the exact replacement by MB number so the CPU is designated for the motherboard, that's why couldn't fathom out how it wouldn't post.
I Always check the power supply first - if they bring it in, which 9 out of 10 customers don't.
The memory was checked for errors etc. I even swapped memory for same type - but no joy.
It turned out to be the memory modules, the MB was a REV:1 and the I was sent was a REV1.2, and it didn't like the 1Rx8 PC3 12800S memory.
I stuck in 2Rx8 PC3 8500S and away she went. Yahoo.
Any MB I've changed in the past always worked with the memory that was in the original MB, so that's one i'll have to watch out for in future.
Just glad I got it working, I didn't want it to be the first laptop I couldn't fix as I was recommended to the customer.