The modem in 3G kindle DX is not downloading

Can I replace the modem in my Kindle DX?

I restarted 3 times

I have reset to default 3 times but still no luck

I have 5 bars with 3G and can access the Kindle Store. I just can't download anymore

I called Kindle support and they said that the modem is not working anymore

I went to the 611 page and it says

Modem state --Sleep Mode

Phone state ----CDMA Idle

Call State ----Connected Dormant