T20 Battery/AC Power problems

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techracer · #1 Post by **techracer** » Sun Dec 18, 2005 3:50 pm

Greetings all, I have a T20 P3 650 that I purchased used from a
neighbor. It is excellent physical shape.

I'm having serveral problems with it which all may be related and all
have to do with battery/power.

1st, while using a genuine IBM Battery, the unit will not power on with a battery installed.

2nd, it will never shows the power indicator as "plugged in" it always
shows running on battery. I've tried 2 different genuine IBM batteries
and 1 generic.

3rd, when i'm using the generic batteries, the unit will power on with
the battery in it. With the IBM Bat I have to remove the batter and then while it is booting i put it in and it works but will not show "plugged in". It will actually power on with the power button and battery in when i have a generic batter in it but this also doesn't show "plugged in" eventhough the battery show's 100%charge. When using the Genuine IBM Battery the battery level indicator shows completly discharged and the orange battery light is flashing. I've left it plugged into ac power both on an off for over 24hrs and nothing helps.

I'm really at a loss here. I'm thinking at this point the motherboard
could be bad. I've even tried 2 different AC adapters

FYI.. I can't update the BIOS because it never sees the AC power as
"plugged in" and it's running a few generations old version.

TIA,

Bryan

skygodtj · #2 Post by **skygodtj** » Sun Dec 18, 2005 9:01 pm

Unless you -know- the IBM batt is good, DONT USE IT! From what you write, it is shorted/bad.

If the generic batts work, then it doesnt sound like the mobo. Have you used a voltmeter on the IBM batt? What readings do you get? Do they match/agree with the what the Hardware Maint Manual say are good readings(not shorted)?

TJ

betabill · #3 Post by **betabill** » Sun Dec 18, 2005 10:48 pm

Point of interest: Sometimes a bad battery will pull the AC adapter voltage down enough that the note pad will not boot. Leave the OEM batteries out if they are not going to work.

Are you sure the Thinkpad bios update program needs a battery? I think the advice is not to update the bios with a dead battery and an unreliable AC power source.

techracer · #4 Post by **techracer** » Mon Dec 19, 2005 1:06 am

betabill wrote:Point of interest: Sometimes a bad battery will pull the AC adapter voltage down enough that the note pad will not boot. Leave the OEM batteries out if they are not going to work.

Are you sure the Thinkpad bios update program needs a battery? I think the advice is not to update the bios with a dead battery and an unreliable AC power source.

When I try to turn on the laptop w/ the battery removed I get past the BIOS and then get "low battery error" and it shuts off. It won't power on at all without a battery.

Does anyone know what voltage the battery should be?

And to add to the mix, the "IBM" batteries were brand new. I did get them from ebay so they could be counterfeit I guess. Anyone know how to tell if they aren't real IBM?

Thanks for all the help.

Website · #5 Post by **tfflivemb2** » Mon Dec 19, 2005 10:20 am

techracer wrote:Does anyone know what voltage the battery should be?

According to your Hardware Maintenance Manual (Page 36), terminal 1 should be +0 to +12.6V, and if the voltage is below 11.0V the battery pack wil need to be recharged.

See your manual here:
ftp://ftp.software.ibm.com/pc/pccbbs/mo ... 2p9631.pdf

betabill · #6 Post by **betabill** » Mon Dec 19, 2005 4:47 pm

When I try to turn on the laptop w/ the battery removed I get past the BIOS and then get "low battery error" and it shuts off. It won't power on at all without a battery.

My T-20 runs fine with the battery removed. Check your bios settings, perhaps theres something in CMOS PM you can turn off to defeat the warning.

Website · #7 Post by **tfflivemb2** » Mon Dec 19, 2005 4:50 pm

You might even want to check the voltage of your CMOS battery. Sometimes CMOS batteries can cause all sorts of weird responses.

betabill · #8 Post by **betabill** » Mon Dec 19, 2005 5:08 pm

Yeah, my first reaction would be to change the CMOS battery if nothing else works. The one in my T-20 measures 2.85v but I'll order a new one just the same.

techracer · #9 Post by **techracer** » Mon Dec 19, 2005 5:11 pm

betabill wrote:Yeah, my first reaction would be to change the CMOS battery if nothing else works. The one in my T-20 measures 2.85v but I'll order a new one just the same.

Is it supposed to be higher?

Website · #10 Post by **tfflivemb2** » Mon Dec 19, 2005 5:15 pm

The CMOS is generally about 3.3V.

These figures are also available in the Power Checkout portion of the Hardware Maintenance Manual that I provided a link for earlier.

T20 Battery/AC Power problems

T20 Battery/AC Power problems

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