I think that "red" is not intentionally red but caused by the defective Denise, who is, in fact, in charge of video output.
Intentional "red" is only used when the checksum of the Kickstart ROM is wrong.
I would also like to add (discovered through experience) that a WHITE screen could indicate there is something wrong with the interrupt system. Interrupts are multiplexed by Paula before being sent to the CPU so check Paula and the socket.
The interrupts can easily checked with DIAGROM.
The interrupts can easily checked with DIAGROM.
