When repairing boards and using donors it is important to note you cannot just swap ASICs between Lynx II consoles, they are not all the same.

Below is a list of known supported chip swaps:

As you can see it seems like so long as the main text is not VLSI (an EPYX chip, called Mikey) going to an Atari branded chip you are ok.

Anything not in this list I have personally not swapped so cannot guarantee.

VLSI EPYX Mikey Variations

The much less common VLSI chips made by EPXY do not work when mixed with the Hayato variants.

Atari Lynx II VLSI EPYX variant



You cannot swap the ASIC chips from a Hayato variant to or from a VLSI variant.

The main ASIC on the VLSI is called Mikey, and the main ASIC on the other variants are called Hayato.

LCD Swap Incompatibility

Another issue is you cannot swap the LCD that came out of a VLSI mother to a Hayato motherboard,. due to the LCD Enable (pin 25) not being shorted to ground on Hayato LCD ribbons. Fix this by shorting pin 25 to 26 on the Mikey motherboard.

The VLSI variant is also only 12 bit color (3 bits per channel) not 16 bit color. The DL0 pin is always ground.