Dodgy Mega Drive carts

Hi

One of my friends has copies of the Mega Drive games Street Fighter 2 and Mortal Kombat 2. Neither recognise when joypads are connected! He tested them on many systems but the results were always the same!

Also, I have copies of Mega Games 2, Mega Games 3, Micro Machines 2 and The Smurfs on which certain sounds can be absent, such as the "character chosen" chime in Golden Axe on Mega Games 2, the highlighter sound in The Smurfs (only if moving up on the password screen), any sound going missing at any time in Micro Machines 2 and on Mega Games 2 & 3, half the beats in the game select music are absent if you reset back to it while playing Golden Axe or Super Thunder Blade.

Could it be that solder in these carts needs reflowing or maybe wires need to be installed? I also tested my carts on 3 different consoles (including the TMSS model 1 console that was included with my £50 charity shop purchase of a Mega CD!) but the results were the same.

Thanks!

 

First try cleaning the contacts on the game using qtip and isopropyl alcohol.