Hope this might help someone or at least somebody might find it interesting.
I picked up a lot of TG16s and found that one of the units would only display a green screen regardless if there was a HuCARD present or not. As with most solid color screen issues, possible causes could be cpu, ram, traces or a combo of any of the above. As I was about to give up looking for broken traces, I felt a ridge by the HuCARD slot. Sure enough, on the right side by the 6280 there was a break that took out 10 traces.
I fixed the four traces that went from the card slot to the 6280. Just in case the crack were to telegraph further, I went ahead and ran jumpers on two more traces. Just to see if I was on the right path, I fired it up. I was welcomed by the Keith Courage title screen!
The remaining 6 traces that were broken, ran to the controller port. Installed jumpers from the vias to the 6280. Fired it back up and was able to control Keith.
I can only assume that the unit was dropped and this caused the board to crack where it did. If you are experiencing solid color screens or no response on your controllers, the areas I repaired on my board might be some place to start looking on yours.
My next step with this TG16 is to recap the board and install a AV mod for composite out. I will replace the tape that is holding down my jumper wires with hot snot once I am sure everything is still working.
I have photos posted here
https://goo.gl/photos/P2NaLCVJXcrhCd4w7Thanks
Chad