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- Posted on
July 22, 2005, 4:26 am
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great, but whilst searching for information about it on the net, I
found the following post on a message forum:
part of which I quote here:
"PLEASE TAKE NOTICE THAT REMOVING THE BATTERY CAN FATALLY DAMAGE YOUR
Actually you are playing Russian Roulette by not using the battery
pack, if you are out of warranty.
I saw a T21 dying on it, and we have a bunch of T20-T22 with dead
battery and thus a CRC 0175 error as well.
BTW: IBM does not advise to using notebooks without battery pack, for
The problem is the Atmel EEPROM, which stores CRC and supervisory
passwords. That chip is accessed a few thousand times during boot-up.
If you potentially step on the power cord during POST, your Thinkpad
in 95% of cases is toast.
You also get the same fatal error in rare cases when you are offline
and your battery runs down to about 2% and you forgot to turn off the
notebook. When you turn on again, the Thinkpad might find the voltage
to low and tell you a low battery error. OR it might boot and break
down 2 seconds later -> CRC error, fatal !
I had this, and you can google for thousands of posts for CRC 0175
errors on thinkpads.
The engineer jerks at IBM (I am an engineer myself and know that
stuff a bit) did not intend to use a rescue default setup in case the
EEPROM is corrupted. They are using the very same Atmel chip
configuration throughout the entire more modern Thinkpad line.
Looking at a heap of about 20 dead Thinkpads with the same CRC
problem, I can only recommend to buy an old battery for cheap, that
does hold a supply of 20 minutes, to be on the safe side, and save
your valuable new battery at 40% charge in a sealed plastic box in
In this configuration the battery deteriorates very slowly.
BTW: To learn a bit about the new IBM policy, just be reminded that
IBM changed the BIOS on most Thinkpads so that an IBM-compatible
battery won't work anymore. You would have to buy an original IBM
battery for their stratospheric price tag. So better use an old one
as a kind of USV."
Is this true? As someone else says, later on this topic, surely during
booting, the EPROM is only read, not written to (and surely the problem, if
it exists at all, would only occur during writing to the EPROM chip)?
I've searched google.com, and can find little solid information, but
it says the problem occurs with any laptop with a "24RF08 eeprom",
what laptops use this chip?
Incidentally, my laptop is a P3-700 IBM T20, and since for the
forseeable future I will be using it only when I'm at home, and the
laptop will not be moved about at all, I was planning on removing the
battery and storing it away, to (a) save the battery's working life,
and (b) reduce the laptop's heat (as surely the battery must generate
some heat of it's own). Is it safe for me to use the laptop without a
battery (mains only), or am I running the risk of rendering my laptop
Thanks for any answers.
Re: Is this true? A potential laptop destroying fault?
Assuming your T20 is similar to my T22, as long as your battery is above
about 95% charged, there is no charging current going to it. Therefore there
will be no heat generated by the battery. I have never run my two TP's
without their batteries in and both the 4 y.o. T22 and 7 y.o.560X have
original batteries that still hold a decent charge. Since I usually have the
laptops plugged in while using and unplugged when they are shut off, neither
battery has seen very many charge/discharge cycles. Perhaps that is what has
saved them or maybe just dumb luck. Whatever, I think people get a bit
overly anal about laptop batteries.