Where is the Li Coin cell in a Sony Vaio model PCG-7A2L

http://home.comcast.net/~nw_systems/vgnFS.pdf

does that help at all?

It might help if I need to remove the Mother board but it doesn't show me where the Li coin cell is.  I assume this computer has one.  The clock does not keep time when the computer is powered down so I am assuming it's the coin cell.

The answer to your question, sadly, is: you can't find one because it's not there.  Most laptops these days do not use one.

http://techrepublic.com.com/5208-23-0.html?forumID=101&threadID=302349&messageID=3020033

So the clock uses the main battery when it is turned off ?  Thanks for your response.  At least I didn't have to completely remove the mother board and then find out there isn't one.  I had to replace the power jack anyway.

Well, it should, whether it has a battery or not.  But when the main battery is out, it would draw directly from the Smart Socket described in the link, which has an integrated lithium power source.  More technical details at this link:

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2635

Also, these guys:
http://www.gearslutz.com/board/geekslutz-forum/377375-akg-adr68k-loses-its-mind.html
mention that if you're the adventurous solder-onto-your-laptop-motherboard type, you can get a replacement Smart Socket from Jameco for $4.95 a pop.  I haven't verified that, but I would imagine they're inexpensive.

Hi Slinkygn,  I have the mother board apart and I don't see a smart socket anywhere.  According to the data sheet it's a pretty big socket/chip and would be hard to miss.  Am I over looking something here ?  Do you think this laptop only runs the RTC off the main battery and maybe uses a supercap for short term power outages ?  Any other ideas are very welcome !

I think this anwsers it: "Sony and other NB Makers use what is called Smart Socket Technology where the power supply for the RTC when the computer is not in use is provided either directly by a Smart Socket below the IC or by incorporating the Smart Socket Circuity onto the M'Board.

This comprises one or more Electrolytic Capacitors along with Voltage Regulation Circuity to provide Power for the RTC when the unit is not in use and or the Main Battery is flat.

This is better as it doesn't need replacing regularly or run the risk of leaking over time. It is also recharged when the Main Battery is in the NB and also when on Mains Power so it acts like a Rechargeable Battery but is far cheaper saving you money in both Parts and Labor that would otherwise be require to be spent every few years to replace the CMOS Battery.

Sony like all the other NB Makers for security uses a Separate IC to hold any Power On Passwords so even if the BIOS Chip was to be removed from the M'Board you will still be unable to bypass the Owners Security and gain access to their Data if you had received the NB from a Thief. The BIOS Chips are also soldered onto these M'Boards so you have 2 choices here buy a New M'Board or take it to a Authorized Sony Service Agent to bypass any security that was used.

This is all stated clearly in the owners manual if you care to read it.

Because the components on the M'Board are all Surface Mount you require a special soldering station to remove and replace dead components. Well used to have one of these 25 odd years ago that allowed small scale repairs to be done to any Surface Mount Circuit Board and these started around the 40K + Disposables mark and you are unable to do anything to one of these M'Boards without at the very least a Soldering Station like that or better. The proper Repair UV Welding Stations for this type of work start around the 3.5 Million Mark and work up from there. Because of the costs involved in these Soldering Stations unless you are working for the Circuit Board Maker it is far cheaper to replace the Circuit Board than to attempt to repair one. If you attack any Surface Mount Circuit Board with the wrong type of Soldering Station you will completely destroy the Circuit Board so people with any sense don't even try.

The reason that you can not find a CMOS Battery is quite simple really there isn't one."

Yes, if you'll note, your copy/paste is the first article I linked to.  My answer concurs with the last line: "The reason that you can not find a CMOS battery is quite simply really there isn't one."

The Smart Socket integrates the CMOS chip and the power source.  It's not trivially small or anything, so it should be findable -- I'd look again.  It is integrated with the CMOS, so if you couldn't find it, you haven't found your CMOS chip yet -- and I assure you, you definitely have one of those!

I cited a few links after the first article I posted (the one you copy/pasted), because it is not completely accurate -- the Smart Socket does not use electrolytics for power, for example, as any electrolytic small enough to integrate with the socket like that wouldn't last for more than a few seconds, perhaps a few minutes at best, in this application.

But as far as the original question -- like I originally mentioned, there is no battery, and the power for the CMOS is integrated into the Smart Socket.

Oh, one more inaccuracy in that article, which may affect you more directly:

I'd love to sell that guy a "Repair UV Welding Station" for around the "3.5 Million mark," but the truth is: 1) you can get a professional SMD station for a few thousand dollars, and a pretty darn solid starter kit for <a href="http://www.web-tronics.com/esdsasmdrest.html">around a hundred</a>, and 2) you don't even need those, as you can find lots of howtos on the Internet on doing SMD soldering with standard tools.  Heck, if you wanted, you could even go with a homemade version of the fancier tools and <a href="http://www.engadget.com/2006/03/07/how-to-make-a-surface-mount-soldering-iron/">make your own hot air reflow tool</a>.  There are many options available for rolling your own repair for $100 or less -- let alone the "3.5 million mark."

Bummer -- looks like the instinct to embed HTML into these things bit me again.  Never turns out well.  Guess I'm going to have to suck it up and learn to tolerate rich text editors someday...