I have had a Dreamcast the controller port stopped working, so I replaced the controller port with another one that did work. The new controller port came from a DC that I had that had a bad disc drive but the controllers worked. Anyway it worked for about a minute and stopped. So then I tried it the other way taking the DC with the bad disc drive and replacing it with a good disc drive but the controller port that worked previously stopped. So then I bought another DC off ebay I played it for about ten minutes and its controller port stopped working as well. The only similarity between all these is the controller I used on them. What the hell is this just bad luck?
Something might be wrong with your controller, perhaps blowing fuses of sorts when you use it for extended periods of time.
There's a resistor on the controller board that may need to be replaced. See http://devcast.dcemulation.org/mods/repair/repair.php for more information.
Yes and that's what I've been replacing the whole board. However since I tried 3 of these controller boards in different consoles and they keep breaking and the only thing in common is the Dreamcast controller (the thing with buttons on it) is bad and causing the controller boards to go bad?
Stop using the controller if that's the common factor. As for the board, it's better to fix than replace it, and pretty simple if you follow GerbilSoft's link.
As for the third, the one that wont read the discs? Try changing the POT, I'm sure you will get life out of it still.
That's not working the DC resets whenever it attempts to read a disc with no disc in it works fine. I've been doing some reading and I think it could possibly be the motor for the GD-ROM drive if that's the case I think I'll just get another GD-ROM drive if I decide to fix it at all I have 2 working Dreamcast already thanks to GerbilSoft.