Step 1 - remove the ABS outer case. It comes off pretty easy with a sharp knife. just give one of the ends a little squeeze with pliers to get an initial crack in the glue and you're away. It's worth holding the nvram in a sacrificial ic socket to save snapping the pins off if you get too rough with it.
The arrow pointing to the 1 indicates which end is pin 1. Next, step 2 - carefully mill the top away until you hit metal. Don't panic, it's only the battery
Of course, milling the surface down removes the arrow indicating pin 1, but that's ok because there's a 1 stamped into one of the ends as well. Step 3 - carefully remove enough plastic at one side of the battery so you can stick a blade down to prise the battery out.
it's spot welded in, so hold the bottom contact down with a little screwdriver while you remove the battery or you could rip the terminal out of the casing.
Don't go too deep with the plastic removal, or you'll cut through the pin contacts (I got a bit carried away with the grinder, and had to re-solder a pin to it's lead) and lastly step 4 - solder a lithium battery holder onto the two exposed terminals. I used a CR2032 but you could use a smaller battery (or remote mounted battery) if clearance is an issue. The CR2032 has a shelf life of 10 years, and will die of old age before the nvram could drain it - I would have used a smaller battery but that's what I had on hand. The original BR1225 is only 48MAh, so this one is way overkill. So despite what Dallas says, you CAN replace the batteries in these!
So don't chuck out your old ones when they stop working, just replace the battery
ill be trying this one out in years to come
