ok today I pulled some motherboards out of my garage, unfortunately I won't have time to test them but they were put back as working about 10 years ago and in any case I have Others ten just for spares , so if you have even the slightest problem I can replace them.
honestly I never saw a motherboard not working eccept for the volume potentiometer or the gnd of the audio chip.
I have also the last two dead carts if you are in interest then let me know because i'm going to ship your parcel Tomorrow, I will comunicate you the tracking number once i have done.
Have a nice day
Francesco