I have a non-working TG16 that has been sitting in a box for years...
When I bought it, it would seem to work for a little while and then stop, and nothing I could do would get it to work again... It was always the same thing on boot - a solid coloured screen, usually light blue or dark green.
I decided to pull it out of hibernation and do some troubleshooting. I grabbed 2 HuCards off the shelf (Bomberman 93 and Bloody Wolf).
Bomberman 93 loads up and plays with no issues.
Bloody Wolf will boot up to a garbled startup screen and become unresponsive after that.
Looking at the contacts, it seems that Bloody Wolf must be thinner, as the contacts hardly move when the card is inserted, but the Bomberman 93 card causes the contacts to bend all the way as it is inserted and then stop about half way in their positions.
So, I gave it a good cleaning. No difference.
So I grabbed a big mitt full of games to test. With interesting results.
The first picture is of the games that boot up without issue. The 2nd is of the games that either will not boot at all or may boot to a garbled title screen.