Fujitsu Lifebook E546 - No Power

[piernov]

Re: Fujitsu Lifebook E546 - No Power

Between all mosfet pins Source and Drain pins beeps for continuity.

I guess you found the problem.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

I guess you found the problem.

yes it seems very suspicious because the other don't do that...
I will try to replace it, but i need one that could be compatible... i will check one on my garbage boards.
I will report.
Thanks

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

I replaced the 2nd MOSFET.
No lucky, everytime i put one, the MOSFET starts to have continuity... and seems the 19V needed on circuit don't appear...
I removed it once more and check continuity on MOFSFET pins and theres no continuity even on board and MOSFET... so seems another thing starts to make this issue appears.
I checked the resistor between both 2 first MOSFETS, and have continuity but i have 5.7Ohm this a bad or good sign ?

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

Hello once more to all, once again I try to fix this motherboard but anything is wrong with it.
I change the Mosfets and read about them, they are N channel mosfets of 30V and some different amperage values.
So I pick up from another boards Mosfets of same values and type N channel and 30v and almost same amperage.
But no lucky... Board still not working and at the first Mosfet at source I have the 19.35v but on drain i get 0.025mV or very low values of voltage... Could someone try to help me please?
I don't belive in 4 different Mosfets I have them all bad... And on 1st of them everytime I change it...

[mcplslg123]

Re: Fujitsu Lifebook E546 - No Power

Again remove 1st and 2nd dc in mosfet and then measure resistance on pin1,4 & 5 of both mosfets. Dont apply power after removing them.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

Again remove 1st and 2nd dc in mosfet and then measure resistance on pin1,4 & 5 of both mosfets. Dont apply power after removing them.

OK I will do, the values you want them from board or Mosfets pins?

[mcplslg123]

Re: Fujitsu Lifebook E546 - No Power

OK I will do, the values you want them from board or Mosfets pins?

resistance on pin1/4/5 on motherboard.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

resistance on pin1/4/5 on motherboard.

OK, i removed the 1st and 2nd DC In MOSFET.

I check the resistence from RED LEAD on ground and BLACK LEAD on each pin you suggest, the values are:

1st MOSFET
Pin 1 (Source) - 12.28 MOhm (No Beep)
Pin 4 (Gate) - 13.26 MOhm (No Beep)
Pin 5 (Drain) - 215.1 kOhm (No Bepp)

2nd MOSFET
1st MOSFET
Pin 1 (Source) - 12.35 MOhm (No Beep)
Pin 4 (Gate) - 13.36 MOhm (No Beep)
Pin 5 (Drain) - 3.575 kOhm (No Bepp)

Remember all this values are measured with red probe on GND and black probe on each pin of motherboard with 2 first DC IN MOSFETs removed like you suggest m.
Hope this help us.
Thnaks once more for your patience.

[mcplslg123]

Re: Fujitsu Lifebook E546 - No Power

2nd mosfet, pin5-resistance seems to be very low as it is +19V line. So you do have some faulty component down the line. If you have a dc supply, then apply some voltage on pin5 of 2nd mosfet and check the consumption on your psu. Slowly increasing the voltage observe consumption at 2-3 different voltage levels and post here.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

2nd mosfet, pin5-resistance seems to be very low as it is +19V line. So you do have some faulty component down the line. If you have a dc supply, then apply some voltage on pin5 of 2nd mosfet and check the consumption on your psu. Slowly increasing the voltage observe consumption at 2-3 different voltage levels and post here.

Hello I received my PSU already, but I have a question, should I do your suggestion with 1st Mosfet soldered or without it?

[mcplslg123]

Re: Fujitsu Lifebook E546 - No Power

Hello I received my PSU already, but I have a question, should I do your suggestion with 1st Mosfet soldered or without it?

will not make a difference. You need to apply voltage on drain of 2nd mosfet(pin5-6-7-8). Start with 1V/1A and gradually first increase the amp to 5A. If nothing significant start heating, you can gradually increase the voltage. Cmos battery as well backup battery,ac adapter should be removed before applying voltage.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

will not make a difference. You need to apply voltage on drain of 2nd mosfet(pin5-6-7-8). Start with 1V/1A and gradually first increase the amp to 5A. If nothing significant start heating, you can gradually increase the voltage. Cmos battery as well backup battery,ac adapter should be removed before applying voltage.

Hello today i test your suggestion and i apply with my PSU, 19V and 3.4A on board at second MOSFET on Drain Pins, my PSU shows
19V - Seems OK
0.011A - is this fine ?
If i try to turn ON, the power LED blinks only but nothing more...

[mcplslg123]

Re: Fujitsu Lifebook E546 - No Power

So , your B+ rail is fine. You have some other problems which you need to find out.

[nrcslim89]

Re: Fujitsu Lifebook E546 - No Power

So , your B+ rail is fine. You have some other problems which you need to find out.

So what you mean B+ now I get noing sorry...

[Techtiger]

Re: Fujitsu Lifebook E546 - No Power

So what you mean B+ now I get noing sorry...

+19V Line & the Battery

[tiesto23]

any update on this i have same pc with same problem