Just as the cartridge case, box, overlays, and manuals evolved to reduce manufacturing costs, so did the guts of an Intellivision cartridge. The oldest cartridges are noticeably heavier than later runs of the same game because the metal shielding around the PCB was removed. Ultimately, the Intellivision lived long enough to start using surface mount technology, rather than DIP chips.

Inside the shielded PCB

The earliest games had heavy shielding

Inside the shielded PCB

It didn't take long for that expense to be cut...

A PCB with diodes

Quite a few games have diodes on the PCB

A plain PCB

Guess capacitors and diodes were expensive...

Surface-mount PCB

Surface-mount technology at last!