Monday, April 9, 2012

Update on MOSFET Video in the bundle.

An update for individuals that purchased the video bundle.
In the Extras bundle, the  video named DVMOSFETS.mpg 

The initial problem with the board was no lights, no power.  After some diagnosis and replacing the MOSFETS on the front end the unit was recieving power and would loop, turning on, then off. 

Clearing the CMOS and with a Cold Reset it would not revive the unit.

It was determined that the CMOS battery was also drained from sitting too long with a short condition. The CMOS battery should have a minimum of 2v.  Without a charge in the battery, the CMOS settings that are read from the BIOS chip are not saved or stored, the laptop will loop trying to retrieve & store these settings (which will never happen) because of a dead battery. 


This is one item that I overlooked during my diagnosis, because usually the CMOS battery will last 3-5 years under normal use.  But when a unit has a shorted condition (or has sat for a length of time before repairing), the battery will go down to zeo volts, and cannot store settings.

4 comments:

  1. Hello sir ! I have a macbook a1181 doesnt turn on and found 4409 mosfet open on top of the component says 4409 and BA8D2A can you help me to find it here in US THANKS !!

    ReplyDelete
  2. I typically don't repair Macbooks but will try to give tips.

    Does it read open in both directions?

    If you need to replace it, you can get a replacement from AOSMD.com or cross reference the values at "http://www.Fairchildsemi.com" or MOUSER.com

    ReplyDelete
  3. Hello, my name is Antonio and I´m from Portugal. I´ve see your blog and i found it very interesent and usufull. I work in this área, some times i have some difcults on fouding the problems in the machines. Do you have some DVDs with laptops problems? something general, including the problems solutions?
    Best regards,
    Antonio

    ReplyDelete
  4. yes there are videos that can be downloaded - They are at my domain http://www.mayohardware.com and click on the video link at top of page.

    ReplyDelete

I cannot repair laptops for you via the internet, I can only answer questions related to posts. This is because I have not had experience on every motherboard that is out there. Bear with me.

If you do need it repaired. Contact me for quote (US/CDN Only)

Note: Only a member of this blog may post a comment.