When I got my T2, I had the same issues, I took the radio apart, and had a go at re-soldering all the connections to the display, but it made no difference.
The LCD screen is a laminate, and the thin ribbon cables actually passes into the laminate and there is nothing you can do to improve the connection at the LCD end.
It seems that squeezing along the connector edge makes some bits start to work, and others fail. I tried all sorts of ways to get it to all come on, but there were sections that refused to come on, no matter where I squeezed it, so I came to the conclusion that damp had got under the laminate, and corroded the joints.
When I worked for Samsung, the LCD's had gold plated minute terminals on the edge of the LCD, and these were pressed against a striped carbonised rubber, that made the electrical connection between the board and the LCD, and it was purely the pressure of the join that made the connection, and kept the contacts clean. If one failed, a quick wipe with IPA could fix it normally, but sometimes, the rubber connector needed replacing as well.
The next problem is, since the radio is supposed to be married to the ECU/Alarm, you can't just swap one T2 radio from car to another.
I looked into trying to get my unit repaired, but I think because of it's age, most places have moved on, and do not seem to bother with it any more, and the only one I did find, was up north somewhere, and was going to charge more than a cheap new unit anyway. Even then, they were not sure if they would be able to source the LCD panel.
I opted to fit a Pioneer I already had, and got a second hand MultiChanger off of Ebay for it. As mentioned you can get a converter for the main wiring, allowing a different head unit to be installed very easily, but I could not find anything to convert the CD Multi Changer lead, which all seem to be wired uniquely and have their own style of plugs, for their specific manufactures, meaning you can not put a Blaupunkt/Clarion Multi Changer, as installed by Nissan onto, say a Sony or Pioneer head unit. I just ran the new wires under the carpet, from the radio head unit, to under the drivers seat, and re-used the mounting plate from the Nissan MultiChanger, to fix my Pioneer one to.
