Acer Aspire 7720 CMOS battery
It is the RTC Battery now. Real Time Clock battery. Same Ol' thing, just a new name.
You will find it on the Bottom of the motherboard.
Battery Compartment facing AWAY from you, it is to the Bottom left of the motherboard. Right above the black round, Piezo buzzer.
Allow me to show using just the motherboard itself,
I invite you to hover your mouse cursor in the middle of the photo, and use the Zoom In feature.
Go along the Bottom of the motherboard, head to the Left.
Black round, Piezo buzzer, and above it encased in a blue plastic 'rim', is the silver watch style battery.
The blue plastic wraps around the bottom of the battery. There are two tabs coming from the battery, and they are soldered to the motherboard.
It is MHO that the laptop will need to be disassembled, in order to access it.
Don't know, haven't worked on one yet; do not have one in front of me.
Here is the Service Manual. You will need a No.1 Philips screwdriver, or equivalent Jewelers screwdriver.
You will also need an ESD wrist strap, and connect it's alligator clip to a good ground source. Failure to use one means you get to use your laptop, as an expensive doorstop, or paperweight.
I'm gathering YOU know this, but when people read this later down the years, I'd like to make sure they do too.
Go to the 'paragraph' that starts with Aspire 1200. (1200 in Blue)
Drop down to the 12th line (7530G), scroll across, click on the blue - 7720
Battery not available, No I do not recommend soldering tabs to a small bom-b, for those who are beginners. That is a little Lithium bom-b with enough heat applied.
ID numbers should be on it for you to find replacement, or crossover replacement.
Edited by saugen48 - 3/12/13 at 6:19am
Yes, that is the bottom, (I guess. Ain't like I can SEE it, lol!)
Yes. You are correct. The 'arm' (Strap) is soldered to the motherboard.
Guess you are looking at the Negative side. Negative wraps around. Positive contact is in the middle. Positive side does NOT have plastic on it. Positive side has a + sign on it.
No. Laptop manufacturers started hiding the CMOS/RTC Battery a long time ago.
USED to be, you could remove the CMOS battery, and reset the BIOS password.
Now there is a Capacitor, or capacitors; that store a trickle charge INDEFINITELY.
You have to find the CMOS jumper pads, and short them out temporarily.
Yes. They are hidden too!
If it's a little silver watch type battery you are looking at, it is the CMOS/RTC Battery.
Dunno at present. I started looking for a replacement right away.
But don't fret that stuff.
Unsolder the strap from the battery, ON the motherboard side. I don't know your soldering skills sir, but;
A) KEEP away from the CMOS battery with that hot soldering iron tip,
B) and don't burn the motherboard.
Soldering Gun? This = NO IMHO
Too easy to burn the motherboard.
25 Watt soldering iron. Put a tiny dab of Rosin flux paste on it. Helps transfer the heat from the soldering iron.
THEN, if I may suggest, find the watch battery that looks like that one.
Take it, and the old battery down to the nearest 'Mom and Pop' computer repair shop, (i.e., small store), and have the resident tech unsolder the strap from the old one, and solder the strap to the new one.
Rosin core solder now is 'Green'. More environmentally friendly.
Also is a B*tch to solder if you have been out of the game for a while.
How to find replacement?
It's a 3 Volt battery
Just get the same diameter, and thickness.
Just thought about it. The first of the 'drivel' I posted, really doesn't make sense.
I would like to blame it on it is 4:30AM, Ha!
The Positive ( + ) side will be marked.
Also, I know I'm probably dreaming, but I would find a socket that fit's this CMOS battery's male plug connector, and solder it to the motherboard; via a couple of short wires,
Yes. Finding that female connector is kinda' tough. This is where a small computer repair shop, may come in handy.
Old laptop motherboard that uses that type of CMOS battery in a 'bag', and remove it's female connector.
Two pins come up from the motherboard, and go through that connector. The male plug of the CMOS battery, has socket holes.
Ease the female connector off of the motherboard. Now solder two small pins to two wires. Make one Black (Negative - ), and one Red. (Positive + )
You can see if the terminal on the motherboard is Positive, or Negative; by following the + on the Battery.
Solder the Black wire with a contact pin on it, to the Negative connection.
Do the same for the Positive wire, and pin.
Connect the male plug of the CMOS battery to the female connector.
Now insert the pins through the female connector; and into the respective socket holes in the Male connector of the CMOS battery.
Small piece of sticky tape holds the wires in, and holds the CMOS battery to the motherboard.
I'm talking STICKY. As in the tape they use at the post office. That clear stuff.