System Blue GPS problem

[Steve-]

I have just finished building my new system blue. When I fired it up, the GPS worked but kept dropping out. Now it has stopped working at all. The only way I can get it to work is to power down for a good while and then power it up again. This enables it to work for a few minutes and then it shuts down again. Seems like a heat related problem, a dry joint maybe?
Can anyone help me to diagnose this please?
(I cant search for GPS in the forum because searching for three letter words is prohibited.)