eMachines G420 Notebook PC
Meaning you have the motherboard out, and visually see damage?
I can give you the System Block Diagram of the eMachines G430.
Should use the same components as the G420, but can't swear to it since I do not have a G420 Service Manual. You will know by visually looking.http://www.tim.id.au/blog/tims-laptop-service-manuals/#toc-acer
Scroll the page down to the eMachines E430 heading. (E430 in blue)
Scroll across, and click on G430.
[ Ignore the following if you are aware. This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the file name, (G430), it may take up to 30 seconds, before the first page comes up.
At the top of the PDF file is the Zoom In icon ( + ), and the Zoom Out icon, ( - )
Zoom In increases the view, Zoom Out decrease the view.
The page number box at the top is for the PDF file. It does Not match the actual number of the Service Manual. If I refer to a page, it is to the PDF file page ]
Go to Page 13.
Increase the view size.
(I am using dual monitors. An HP 2009M that is a 20 inch widescreen, and a RCA EN-V 26 inch HDTV as my main monitor. View size I'm using on it for the PDF file is 150 percent)
1) DC to DC Interface Circuit is on Page 42. (DC/DC Interface CKT)
2) Power Circuit DC to DC is on Pages 42 to 45.
(Power Circuit DC/DC)
Nope. Is not in there. Part of another manual apparently.
There is a Power MOSFET used, however. Do I know what chipset it is?
This is one example of a Power MOSFET used in a lot of laptops,
Referenced only to help guide you. Most of the time when one of these babies is damaged, it will bubble on the top, or blacken.
[ Remember, use a Heatsink on each J lead of that MOSFET, when soldering the new one in, http://www.radioshack.com/product/index.jsp?productId=2103242
I hope your problem is simply a Diode, or two, or the solder joints of the DC Power Jack are cracked. Re-solder if so.
Damage past this point indicates motherboard replacement.
(Hope you are using an ESD wrist strap, and have it's alligator clip attached to a good ground source. Otherwise the motherboard is now a candidate for a Frisbee )http://www.dcpowerjacks.net/catalog/index.php?main_page=product_info&cPath=3_42&products_id=1486
For additional questions please post in a Comment.