Replacing CMOS Battery for an IBM Thinkpad T42

This video will guide you through the process of replacing the CMOS Battery for your IBM Thinkpad T42
The replacement cost of the battery was approximately $5 CDN
You might want to take note of the location of your existing CMOS battery and how it is secured inside before removing it so you can be sure to install and secure the new battery in the same manner.
Also just a word of caution when lifting the back panel to ensure you don't disconnect the ribbon cable for the touchpad otherwise you will need to reconnect it. This happened to me when I replaced the battery and it wasn't until I restarted the laptop that I discovered my touchpad was not functioning properly and I discovered that I had accidentally disconnected the touchpad ribbon cable. After reconnecting the ribbon cable the touchpad worked again.

[@tinaluke5124]

Use a normal 3 volt lithium battery, make use the polarity is right and you have a good contact, Use tape and a small rubber band around it.

[@bluesteel848]

Having dealt with a lot of Thinkpads in my career so far, I'm pretty sure you only have to remove the keyboard rather than pull the whole unit apart like you have shown here.

[@FIX-IT-Yourself]

Thank you for your comment Ibrahim, but for this particular model I don't think it is possible to remove the keyboard without disassembling from the back as I have shown. If there is a way that you know how to do it by simply removing the keyboard then perhaps you could try to create a video clearly showing how to remove the keyboard to access the CMOS battery and then post it for others so they won't have to go through the whole procedure of removing all the screws from the backside. Vito Casola - FIX IT Yourself!!

[@scodal8636]

Not on this model. OP is right. The CMOS battery is under the touchpad. You can be lazy like me and remove the keyboard and a few extra screws that loosen the main plastic frame enough to sneak some tiny hands in, but it's definitely not UNDER the keyboard. If you removed stuff under the keyboard you could remove the wifi, gpu, cpu, and the heat pipes that keep things cool. I like those where they are though. Oh ram is accessible under the keyboard too.

[@Yrrbnlylsw]

Would this also cause a NO boot condition but the fan turns on after the power button is pressed?

[@leomartin3479]

Bit late but yes, I had the same Problem and if you want to still boot without changing the cmos battery you have to disconnect the power and battery, then hold the off button for 15-30 sec and then reconnect the power sources, now it should boot (you have to do this whole process every time you turn it on until you change the battery)

[@user-cb7kw6sb6u]

Спасибо, полезно.

[@ezehogan]

Not a fan of this at all. I was going to replace the CMOS battery on this laptop I fire up infrequently. I think I’m going to leave it alone. I have an older Thinkpad where a single screw on the underside allows the user to pop out a panel and replace with a button cell. On this unit they used a proprietary battery rather than an off the shelf button cell. Major downgrade in my opinion by IBM.

[@mohitjaiyajaiya6884]

One battery chya