One of these screws is thinner than the others, which I didn’t notice until I started screwing them back in.

Well, I had to try it. I plugged it in and turned it on (with no battery) and it worked! So I’m going to screw everything down and just run it this way. I don’t really need the battery (though I ordered it).

I just removed the battery from my Surface Pro 1. I don’t have the new battery yet. If I try to plug it in with no battery, will I destroy it?

You glue it back in with double-sided tape. You can get it on Amazon, but most batteries meant to be glued in come with the tape already on it. When my new battery gets here, I’m not going to glue it in as completely as it was. Seems like overkill, and it’s too hard to remove.

The 6 screws holding the fans in place should not be removed (3 on each side - heads look different). They just attach the fans to the motherboard.

There’s an additional black ribbon cable (top center in picture) that needs to be unplugged. Also, open the release for the cables before trying to pull them out.

There’s an 18th screw that needs to be removed. It’s in the upper right corner of the picture, but not circled.

On my Surface Pro 1, the screws labeled as T5 are T3.

My Surface Pro 1 needs a T4 screwdriver for these screws.

The Microsoft part number for the OEM Surface Pro 1 Model 1514 battery is P21GU9. The Surface Pro 2 Model 1601 uses the same battery. If you search on eBay for “battery P21GU9”, you’ll find a lot of them - all from Chinese sellers. I just bought one that’s theoretically OEM and brand new (unused) for $35. The seller has a high rating, so hopefully it’s true.