I had the same problem. Symptoms:
Time is never set, always 2009
Turn on the GB580P
Press arrow down
(In an area that there should be GPS coverage) check satellites. If there are no sats showing, the antenna is likely broken
I have a preproduction unit, it may not be the same for others. As I have no warranty, I tried to fix it myself.
I would like to warn that if you are not very good at soldering, dont try this. You may still use the device to record sensors...
Open the device by putting something sharp between the upper lid. The lid is just attached with silicon.
Lift the LCD (it is not attached)
Measure the resistance between the upper part of the antenna and the other end of the antenna cable - see the orange cable. If it is zero, the cable has likely deattached from the antenna.
If you are just semi decent at soldering, solder a replacement cable (like the orange) without dissemble further. The GPS reception will be worse, but the unit will at least set correct time.
To continue, remove the four torx screws and push out the board gently.
Check the antenna connector. The wire is very thin and hard to solder. If you succeed, fixate with glue or something.
Beware of summer cable when reassembling.
I do not have good equipment for soldering or good skills. The connector wire broke when I tried to repair it, so I had to go with the "patch" solution. I would like to replace the cable, but the connector will be hard to find. Even the shield is hard to solder (I skipped the cable, just use grounding). The device do not look good inside now, but seem to work better.