Computer crapped out on mine a couple of weeks ago. Wasn't a real big fan of the unit, but will give the brand new one a shot. If not completely satisfied either one of you can have it for a reasonable price. All you'll need is a transducer (if you're gonna put it on TM).
I have one on the bow and one on the console. So far I like them a lot. Much nicer than the one's that come with the boat. Haven't had any problems yet.
I'm selling a 200dx 1 year old and a wide view with both transom and Tm transducers. Both work fine. Upgrading to Garmin 160's. If any of you 'Bird fans are interested let me know. Probably take $200 for both.
The 128 bases and transducers will work, but the big advantage of the 400 is the tri-beam transducer...which requires a different base and transducer....you're not getting the full advantages of the 400 by using the same bases and transducers as the 128.