I own a 6102i which works just fine. A friend brought what appears to be a lightly used 6102i to me so he could determine if it works before he buys it.

I put my battery and SIM card in it but it will not power up. Since I don't know if the card is phone-specific, I took it out leaving only the battery. It still doesn't power up.

Inside the phone on the plastic under the battery is a round red sticker. My phone has a white sticker in the same place so I am wondering if the red sticker indicates the phone my friend brought to me is DOA and is usable only for parts.

The red dot means the phone has been wet ... and that means it is probably dead.
Regards

Agreed! That sticker should be white. It's made out of litmus type paper but with a sticker instead. If water damage every happens, it turns red in an instant. This can even happen if the phone has been in someone's pocket and sweating.

Thanks for the replies. I wondered how the red sticker got on there and suspected it might be a reactive-type of paper.

Since the casing isn't as scratched as my phone I think I will buy it for parts.

When the sticker was applied when new, it was white. It was placed there from the factory to detect moisture. This is a sticker that's about the size of a pencil eraser head.