Corrected entry: The DHD of the second Stargate can be seen. It has a point of origin different to that from the gate found in Gizeh. However, after SGC starts using the Antarctican gate at the end of season 3 the glyph indicating the point of origin on the gate and in the computer systems is still as seen on the gate from Gizeh.
Corrected entry: Carter and O'Neil get trapped on a planet where the DHD does not work, they say that eventually they may get rescued by another team, however if the other team gets there then how are they themselves supposed to get back since they cannot dial home and neither can SGC dial up to them since it is said countless times that you cannot go through a wormhole unless you dialed it, i.e. it is a one way thing.