Strange laptop issue

Jet-Fighter7700

Jet-Fighter7700

Honorary Master
Joined
Mar 12, 2008
Messages
47,440
Reaction score
23,393
Location
Somewhere Different
Hi all, thought I'd bounce a few ideas here,

I have a lenovo t420 laptop, not turning on,
Remove battery, do flea reset,still won't come on,
Remove CMOS battery, still won't come on,

Only way for it to turn on is no CMOS and no battery.
As strange as that sounds,

Funny thing is when the PC is now on in windows, the battery gets picked up, and shows charging,
But restart and won't come on

So not sure what's best to swap? CMOS battery or main battery.
Or is there something I'm missing here?
 
Use multimeter from hardware store, two needles and meassure voltage on the CMOS battery.

Regarding the main battery, not sure. On some models battery voltage is present all the time on the V+ and V- pins. Google for it and for pin layout and if you can't find, post there, maybe I can do.
 
eg2505 said:
Not this one, its that one covered in plastic with a wire type....
Click to expand...

It's a normal battery covered in heatshrink. Heatshrink you can get from the likes of mica, battery from most shops.
 
eg2505 said:
And the crimping of the connector?
I mean its really small connector at the end.
Click to expand...
This is right question. :) Problem is with attaching wires (together with connector - looks like a clue, isn't?) to the new battery. Unfortunately when soldering, heat will likely destroy the battery. Such contacts are typically made by a fine spot welder. I had been even tempted to make such device myself. :)

http://www.instructables.com/id/DIY-battery-tab-resistance-fine-spot-welder/
http://www.instructables.com/id/DIY-Arduino-Battery-Spot-Welder/
 
Replace the cmos battery. (R30odd for a 2 pack if its the CR2032. Avail at pnp, security, watch shops etc.

Start laptop on mains without battery.
Insert battery.
Leave for a couple of hours to pass
 
Replace the cmos battery. (R30odd for a 2 pack if its the CR2032). Avail at pnp, security, watch shops etc.
(edit: I see you have a battery with a different attachment. Try below first if you prefer. Then replace cmos battery if you wish or if problem persists.)


I hope it has an easily removable battery.
Start laptop on mains without battery in.
Insert battery. Do not shut down the laptop. Tip on its side to return the battery.
Leave for a couple of hours to pass while charging. IE at least 2.
Then restart while plugged in.
After that is should start up on battery or mains.
 
Last edited:
sajunky said:
This is right question. :) Problem is with attaching wires (together with connector - looks like a clue, isn't?) to the new battery. Unfortunately when soldering, heat will likely destroy the battery. Such contacts are typically made by a fine spot welder. I had been even tempted to make such device myself. :)

http://www.instructables.com/id/DIY-battery-tab-resistance-fine-spot-welder/
http://www.instructables.com/id/DIY-Arduino-Battery-Spot-Welder/
Click to expand...

I've had luck before with using an abrasive (file/sandpaper etc) on the battery surface and then using a soldering station at max temp to solder the wires followed by heatshrinking the battery and wires. Even done this on AA/AAA cells before.

You can spot weld the contacts with a 12V car/bike battery if you know what you're doing.
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X