Help can someone identify this?

Status
Not open for further replies.
T

tonyh04

Newbie level 5
Joined
Feb 18, 2010
Messages
9
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Visit site
Activity points
1,350
Hello, I have a laptop motherboard which has a faulty power plug and it has burnt some components. Can someone please identify the component marked L20 (near the top of the picture) as I need to replace a similar component. Thank you.

 

L stands for inductor in circuits so it must be an inductor but for value of the inductor you have to check the markings on the top of that component. or check for service manual.
 

    T

    tonyh04

    Points: 2
    Helpful Answer Positive Rating
Hi,
HAs it a double switcher, maybe L86 was the same?
Can you tell/check Types/codings from the nearby ICs in the part_often is possible to find the component values from an application note too...
K.
 

    T

    tonyh04

    Points: 2
    Helpful Answer Positive Rating
Ahhh its an inductor. Unfortunately it has no markings on any of its sides. I took it off to look. Its L86 im looking to replace. I think L20 is the same judging by the dimensions.
It looks like im stuck, I have the service manual but it has no schematic so I do not know the value. My knowledge of inductors is just less than zero, is there any way of measuring the value of an inductor? using just a multimeter.
Can I just stick any inductor in there and hope for the best? as you can see I have temporarally soldered a link across the contacts, this is the last resort as it will either not work, or fry the entire motherboard and burn the house down.

Karesz I do not know what a double switcher is, I just wished it were a resistor or cap, then I could deal with it easily.
 

give some details of your laptop like make and model and try to search the circuit diagram for that it will be much easier to repair the product. In SMD components you can not decide the value by size. lots of components are same size but deffrent values.
thanks.
 

Its an Advent 6413 also known as a Gericom Webgine N340S8. I have the service manual but it has no schematic of the motherboard components. Its an old laptop, but I only want to use it for logging data from temperature sensors.
 

... I do not know what a double switcher is...
Click to expand...
Hi,
Some IC which has 2 switcher on chip.
Their are designed often with the same L value...
Can you measure its value pls_its usual 2-100 uH, but is i.e 330uH possible too!
K.
 

I have looked at the service manual, all inductors shown are made by Murata (using the murata codes), I think the one im looking for is a Murata BLM41 series inductor. Unfortunately no one sells these. Can someone suggest an inductor with these specifications: 150ohm @ 100Mhz, 200mA, 0.7ohm DCR(max), package size 1806 (or smaller with the same spec). Thanks

Found some at Farnell UK, will report back when I install.
 

Hi,
Pls check these webside_who are the seller for you:
h**p://octopart.com/parts/search?q=Murata+BLM41&js=on
K.
P.s.:
It isnt an inductor>> its a yoke, has relative low Q, but a high bandwidth for wide band damping...
You can buy surly some similar, maximum with a litle other measures, but itsnt a problem.
 

    T

    tonyh04

    Points: 2
    Helpful Answer Positive Rating
Ok bought some of these BLM41PG471SN (470ohm @100Mhz, DC current 2000mA, max DCR 0.05ohm)
and these BLM41AF151SN1L (150ohm @100Mhz, 0.7ohm,DC current 200mA, max DCR 0.5ohm)

which one is the right component?

because it it a power input circuit I think it is BLM41PG471SN because the current rating is 2A where the BLM41AF151SN1L has current rating of 0.2A.

Help please.
 

Hallo Tony,
Thja, You knows the original documentations data...
Fror s simple function is surly enough a schort as normal wire, otherwise; its not enough for EMC damping, for that need you a ferrit bead(some yoke construction) over they wire...
Do you have the original Murata code, or where is these spec from: "150ohm @ 100Mhz, 200mA, 0.7ohm DCR(max), package size 1806 " pls?
K.
 

I have the service manual, but it has no schematic of components. There are some schematic of some ports which show inductors, these have Murata code numbers, so I looked for inductor with package size 1806 made by Murata and came up with the two I have bought.
I have 50/50 chance of having the right ones, if I install the 0.2A inductor and it burns quickly I will know that the 2A inductor will be correct. Murata state that the 2A inductor is for power circuits, I guess this is the correct one.
I have no way of testing L20 so do not know what value L86 should be (the original inductor was all burnt up). Its all just guess work.
 

Ej-ej, it will be possibly wrong!
you have less as 50% chance, than it can be some uH up to some 100uH(as I wrote it early), or even a yoke only as your type Nr suggest_if its ok for these inductorr!
CAn not follow the schematic of inductor, what kind of pin from & to is it connected, & what is the semiconductors code?
K.

Added after 1 minutes:

You see your yokes & inductors are practically the same as two/three padles in car; both are padles, but the one for acceleration & the other for deceleration or even cluthcing...
 

Hey Tony,
whats your progress pls?
Possibly is better to order same case type inductors as ie 10/22uH, if its in a switched pwr supply_they are more realistic...
K.
 

hey K im still waiting for the parts, some are coming from the US and the others are coming by courier.I will look for some lower value inductors
 

I would rather expect a 6A Murata BLM41 ferrite bead than a 2A type, because notebooks don't have below 3 or 4 A current.
I understand, that you only guessed about the correct type. Didn't the service manual tell a type? If I read the picture right,
the SMD fuse in series with the ferrite bead has 6.5 A rating, the ferrite bead shouldn't be much below.

In any case, the ferrite bead is an EMI filter, that's not actually required for operation. So placing a wire, as you did before,
should be sufficient, if you still can use your radio in the vincinity. Or are you required to restore the original state?
 

    T

    tonyh04

    Points: 2
    Helpful Answer Positive Rating
Hello FvM, your right I have only guessed the value of the bead I want because the original was all burned out. The service manual did not have the schematic, but all the inductors shown have Murata codes. I then looked at the Murata application notes for the 1806 package size and came up with the 2A which is recommended for laptop DC-DC convertor circuits. My electronic knowledge is very limited and I only have a multimeter to use for test equipment.
thank you for your help
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…