We have a Cuisinart DGB-600. Lately, when brewing

Hello g_daniel,
Your units problem may be due to a filter problem. I am most familiar with the cuisinart dcc1200, but I may be able to help you.
Your described problem may be one of two problems. Let's start with the easier solution first. In the DCC 1200 there is a filter "stick or column" in the left rear. Pull it out and remove the clogged carbon filter(s) that are in there. Shine a light into the receptacle and remove the debris in the bottom. It is likely that this is causing the problem with you machine needing to be started on multiple times. See if this solution works. If it does, you might run 8 cups of water and 4 cups of vinegar through to help decalcify the units plumbing. Do this once or twice and then rinse with at least one pot run-through of clean water. If this works then you are good to go.
Next, if this does not solve your problem we can do the following: unplug the unit and lay it on its back. You will need a #10 torx driver (hardware store if you don't have one) to remove the bottom cover plate. There are 4 torx screws holding it on. When removed, you will find 2 orange hoses. Carefully attempt to remove the left hose without splitting. I used a eyeglas screwdriver to loosen it up. If it splits, just cut off the split and stretch it to reconnect when time comes. As you look into the hose you will find a little black valve inside as well a some gunk. Clean it all out with a fine wire as best you can. Rinse well. Attempt to reconnect the hose back onto the pipe. Slip the pipe clamp back into place. Replace the cover and screws and you should be good to go again. This is not as daunting as it may seem. You can do it. :o) Good luck! If this answer helps, please leave positive feedback for me. Much appreciated. Regards, NormanZ