Mobo battery---what a pain!

[southpaw13]

So I am constantly battling the "QMOS checksum error press F1" issue.  I change the battery and it is fixed for awhile.  Has anyone tried hardwiring in a bigger battery at the same voltage?  I don't want to mess if it for another 10 years!  I did search on the board and could not find an answer.  Maybe use a 3 volt lithium camera battery?  That would last longer right?

Any suggestions how to do this?
Thanks,
Southpaw

[DaOld Man]

Those batteries should last 2-5 years or longer. Make sure you are using the correct one, check the manual or google it if you dont have one.
Also make sure the battery is snug in the holder. I had one once that had a bent tab that would allow the battery to loose connection.
Simply bending the tab back towards the battery (with the battery out) fixed that. I have seen a very few MBs that had rechargeable cmos batteries,
but they were soldered in.
I suppose it would be possible to solder wires to the tabs on the battery holder and run a bigger off-the-board battery, but make sure it is the same voltage.
Connecting the batteries in parallel would greatly increase the life of them, but all batteries have a shelf life, so eventually you will have to change it even if the circuit draws nothing.

[southpaw13]

Thanks!  My problem is that my games do not get enough play time so they drain faster.  Also, i made a few for my nephews and I already needed to make a few house calls.  I was thinking about going to radio shack and get a two AA battery holder that has the wires coming out and then soder it in.  Can I just tuck the wires in the battery holder while the original battery is still in it?

Thanks,
Southpaw

[DaOld Man]

Can I just tuck the wires in the battery holder while the original battery is still in it?

I dont know about that. I guess you could, but what if the wire came out and touched something it shouldnt?
If you really want to move the battery off board, I think removing the watch battery and soldering the wires to the tabs would be the best.

You could also use 4 battery holders (or two pairs), each pair wired in series to give you 3 volts, then the two pairs wired in parallel.
That way if you change the batteries in pairs, like pair 1 in six months then pair two in the next six months, the CMOS will have power during the battery changes, so you wont loose cmos info during the change.

[jfunk]

So I am constantly battling the "QMOS checksum error press F1" issue. 

I hate this.  I worked so hard to make my computer's startup sequence look NON-computer, but now I have to boot up prior to anyone getting to my house so I can hit F1...  I'm too lazy to change the battery 

[boardjunkie]

http://www.radioshack.com/product/index.jsp?productId=3795415

Onna those would last forever....

Its "aa" sized so you can use a single AA battery holder and solder the wires to the mainboard. Watch your polarity whatever you do. Hook it up backwards and yer likely to fry the cmos ram....

[southpaw13]

OK-got it done!  $2 at radio shack.  A little more for the batteries.  They say they have a 15 year shelf life.  It booted right up minus the F1 screen.  Thanks for the suggestions and I will report back in 10 years or if they batteries die...whichever come first!

I would highly suggest trying this if you have the same problems...

Thanks-picture attached,
Southpaw

[DaOld Man]

Looks like a good job!
maybe your nephews wont have to worry about changing them until their kids start complaining about the problem. Just be sure to tell them how to change the batteries.

[southpaw13]

I hoping the computer dies before the batteries....maybe their will be no need for AA batteries in the future!

[Beley]

....Can I just tuck the wires in the battery holder while the original battery is still in it?

A bit late since you already found a solution, but for anyone else thinking of doing that(the above quote), don't.  The different internal resistances of the different types of batteries will cause problem when connected in parallel.  best case, batteries drain quickly.. Worse, batteries leak allover motherboard. Even worse batteries heat up and catch fire.