ASUS N61JQ won't start

[DeniS182]

Hi all,
I have problem with this notebook. When is power adapter connected , after press a power button only led around this button once blink and notebook don't turn on. After few pressing power button led stay on , but nothing happens, only black screen.. What you thinking? What is the problem? Is this graphic card problem? I ask you before disassembling.. thanks for answer.
Denis.

[jasko_jacker]

Re: ASUS N61JQ won't start

In these cases, it is usually necessary to verify some voltage on the motherboard (bios ic, Super I / O, 5V and 3V, etc.) and you need to disassembly I assume you have to change ram ...
After disassembly of the unit and tensions are present it is possible that there is a problem of bios and you can try to reprogram If you have the basic tools (multimetr etc.) I can help if a schematic is on the web.

[DeniS182]

Re: ASUS N61JQ won't start

Thanks for answer!
I disassembly it yesterday and problem is in motherboard. Some component near voltage input connector is bad - I attached a photo. I mean it's a mosfet in SOP8. I don't measure other components, I can find schematic first. Someone have schematic of this notebook?

[DeniS182]

Re: ASUS N61JQ won't start

Hi,
can someone help me with this? I found service manual only for model N61JV. I attached this manual here and some screens.
Second mosfet near this burned-out is 4435BZ and in schematic both mosfets are same. I have 4407A mosfet to replace this burned-out mosfet and I don't sure if this is good replacement? I have to replace both mosfets for same or I can replace only one bad mosfet with 4407A? Thanks for answer !

[meritosari]

Re: ASUS N61JQ won't start

better you clean and desolder/remove burn mosfet first. then check if any short component especially another 4435bz.
try with ohm red probe to component and black probe to grnd

its really difficult to read pcb without marking, better way with board view + schematic

sorry for bad english

[ktmmotocross]

Re: ASUS N61JQ won't start

what else marking u need to know? u see J8803.

[DeniS182]

Re: ASUS N61JQ won't start

HI all,
I replaced burned out mosfet and also second mosfet near this burned out. I used same type as original - 4435 - in schematic are both mosfets same. PCB under burned out mosfet was burned too and I had to connect gate of mosfet with wire - pad was damaged, but I measured where was connected .. Also I replaced 4 shorted ceramic capacitors. After replacing these components I connected motherboard to regulated power supply with current limiting set to 300mA, but it is not working. Without current consumption.

edit:
Now I look better to schematic and in there are mosfets drains connected to each other and on PCB are sources connected to each other.. Now I mean I need replace mosfet who I replaced before, with N-channel mosfet. I attached schematic and I don't know where on pcb is the part which I mark ???. Schematic from N61JV is too different. I'm confused now. Can someone help me? Thanks!

[meritosari]

Re: ASUS N61JQ won't start

try this, its a little different with your project, but i think its can help you.

[DeniS182]

Re: ASUS N61JQ won't start

Thanks for it, but i don't know how to open these files?

[meritosari]

Re: ASUS N61JQ won't start

Thanks for it, but i don't know how to open these files?

asus tsic

[DeniS182]

Re: ASUS N61JQ won't start

I opened it with this program thanks. This pcb layout is same as in service manual who is attached in fourth post, but not same as my motherboard.. Can I find type of mosfet from this pcb layout in asus tsic? I opened some .dat file in excel, but for example PQ8903 is no type written here. Only values of resistors, capacitors, inductors...

edit:
I found this motherboard on ebay and I asked the seller what is written on these mosfets and he answered me - 4835gm a3779g and both are identical.

[DeniS182]

Re: ASUS N61JQ won't start

I can't find where is input voltage connected. I measured 19V only on connector. Also I tried to find it with ohm-meter..Connector is good soldered to pcb and input voltage is not elsewhere than in the area marked in the picture. Can someone help with this?

[meritosari]

Re: ASUS N61JQ won't start

i think after dc connector is L6003 & L6004, see my attachment. look like as caps, but a bigger than caps. but be carefull.

i'm not a master, so be patient. wait and see if any guy for better suggestion, cause its 19v rail. very dangerous to other component with low volt

[DeniS182]

Re: ASUS N61JQ won't start

Good idea! These are capacitors what I replaced because they were short-circuited ( 0.6ohm) but if these is L6003 & L6004 it's makes sense. Thanks and I wait for other answer.

[DeniS182]

Re: ASUS N61JQ won't start

Because no answers here I tried jumped this L6003,l6004 and now it doing the same thing as in first post. Only all leds blinks once.. Can someone help me? I will measure what you need to help me. Thank you.

[DeniS182]

Re: ASUS N61JQ won't start

Without CPU motherboard stay on..

[meritosari]

Re: ASUS N61JQ won't start

without adapter and battery, try to measure the resistance in all large coil.

[DeniS182]

Re: ASUS N61JQ won't start

0.3-0.4R on all

[Th3_uN1Qu3]

Re: ASUS N61JQ won't start

You're measuring wrong then. You should measure the resistance between one end of the coil (doesn't matter which one) and ground, which would be one of the mounting holes of the motherboard.

[DeniS182]

Re: ASUS N61JQ won't start

Of course , sorry. I marked two coils with low resistance on picture. Only on 1 coil I measured stable resistance , near cpu - 10-12 ohm. Others are not measurable, often changing the value on lcd.