I have a HP Compaq 6735S laptop and the CMOS battery is located so deep into it that the laptop needs to be completely dismantled to get at it. I've also heard that the usual removing the CMOS battery for 5 minutes trick doesn't work on this machine. I'm getting the internal Battery error code 601 upon startup, unless I remove the ION Battery and power from the electric. The ION Battery doesn't want to charge, even though it's barely 2 years old. I've heard a hard reset involving removing the power supply, battery and hard drive before holding the power button down for 30 seconds is the way to reset the CMOS battery and possibly solve the problem. Can anyone confirm or give me an alternative solution?
Update:Thanks guys, so if it's the Lithium ION battery that is dead, then the CMOS must be still ok? Does that mean that I can continue using the laptop from the eletricity power until I get a new Lithium Battery?
I could replace the CMOS battery but it's a huge job due to it's position. But if I don't need to then great! What do you think?
Answers & Comments
Verified answer
Your CMOS battery is dying and needs to be replaced. Buy another battery, and replace it. Or take it to a technician and they replace it.
You don't reset the CMOS battery you replace it. When you replace that battery the bios will be reset to factory defaults. You need to open up the case to replace the CMOS battery. You will need to remove the screws on the bottom of the case to remove the bottom Bessel and get access to the bios battery.
Check out these sites here:
http://www.insidemylaptop.com/disassemble-hp-compa...
http://bizsupport1.austin.hp.com/bc/docs/support/S...
It shows you how to disassemble your laptop.
edit:
The CMOS is a chip with code on it that initiates the start up and boot up processes. Its located on a eeprom (memory) chip that is soldered onto the main circuit board, also know as the motherboard, in your laptop.
You cannot replace that chip without replacing your motherboard. You most likely do not need to replace it anyways. The error codes you get are because the cmos cannot be fully powered. There is not enough power going to that chip. That is happening because the battery inside your computer, not the external battery for the laptop its self, is dying.
Yes, the cmos battery is a lithium-ion battery but its not the battery that is outside your computer powering your computer when not plugged in. The cmos battery looks like a watch battery .. just bigger is all, and is only for the CMOS its self.
David, its not so it can boot quicker its so it can boot period. Without the cmos being powered by the cmos battery you are dead in the water.
Also, there is a clock on the cmos, in the bios, that keeps the computer in sync. Without power going to the cmos/bios that clock will not work. Everything is timed on a computer so that clock working is essential to the operation of the computer.
Because the battery error only comes up when you have the lithium ion battery installed, that strongly suggests that it is referring to the lithium ion battery. "Internal" in this case simply means it's slotted into the machine rather than attached by a cable. It most likely doesn't mean the CMOS battery.
What the sales people don't want you to know is that lithium ion laptop batteries usually last a maximum of about three years. Two years is a good age for such a battery, especially if it's a heavily used laptop that's usually plugged into AC power. For the absolute maximum battery life, you have to remove the battery when running off AC power, store it in a cool location and maintain its charge at between forty and sixty percent as much of the time as possible. Some people go as far as storing them in a fridge, but you do need to be careful to avoid condensation if you do that.
That MIGHT solve the issue, but there is no guarantees.
Doing a hard reset of the BIOS is only necessary IF you cannot access the BIOS through the computer itself. Since you can turn the computer on and enter the BIOS menu, you can reset the BIOS to defaults through the BIOS screen.
But, considering the battery is 2 years old and it is a Lithium-Ion battery, resetting the BIOS would likely do nothing for you.
Li-Ion batteries are perishable, and being in the hot confines of a laptop SEVERELY shortens the lifespan of this type of battery. Most likely the battery is simply dead.
cmos just saves the bios settings so the machine can boot quicker, if the battery was dying then you would have to go through a bois setup every reboot. newer cmos batteries because they are so hard to get to are often rechargable now.
never heard of a flat battery causing boot issues but it must be possible as they keep sticking bits in them to stop you from buying cheaper batteries.
if it boots up and runs fine without the battery and no cmos problems then just carry on using it and maybe look on ebay for a new or second hand battery. sometimes you can re-cell old batteries but this sounds like the controller chip wont let you.
I sometimes manage to restore dead batteries by passing a small charge over the cells from a standard 12v mains charger 500mA or so, I run a meter over the set up so I can see if the battery is holding any charge or allowing current through. sometimes though the cells come back to life but the controller chip doesnt.
what happens if you boot it then plug the battery in?
Just to add again, if I plug it in and power up it seems to work ok, although my brother says that this didn't work for him previously. If I then plug the battery in it says 95% power, not charging.
Another time I plugged it in with the battery in it, powered up, took the battery out, and then slotted the battery back in and that time it started to charge up to 100%. However, the next day the error code 601 appeared again and I was back where I started!
Hp 6735s Battery
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