Electrical Problem

I just had the alternator changed in my 1995 2.2L GMC Sonoma and the truck is still not charging right. I’m getting about 12 volts on the meter on the inside dash board and at the battery on a volt meter. The battery is about 6 months old and the Tech at the shop advised that it tested fine.
My question to you is could my problems be coming form the Voltage Regulator? If I'm not mistaken the VR is built into the alternator and if I just got a new alternator then the VR should be good.
Besides the VR as being a possible problem could it maybe be the plug that plugs into the alternator that could be going bad and telling the alternator that the vehicle don’t need to be charged? Someone also told me that if could be a fuse. I checked all of the fuses in the pannel near the door and they were all good. I looked under the hood and could not find a fuse pannel but found the fuseable link. I tested it and it tested good as well.
If some one knows of where the second fuse pannel might be or another step I can try to get this thing running please let me know because I'm at a loss right now. Thanks.