IMPORTANT: When swapping the main logic PCB on a 512K Macintosh, perform
the following:
1. CHECK FOR 800K ROM UPGRADE ON "BAD" PCB
Check the ROM installed on the malfunctioning PCB. If the ROM
part numbers are 34X-0341 and 34X-0342, then they are 800K
upgrade ROM and you should proceed to step 2 of this procedure.
If not, then the bad PCB doesn't have 800K ROM so you don't need to
worry about transferring the upgrade from the bad PCB to the
new PCB.
2. SWAP 800K ROM FROM "BAD" PCB TO "NEW" PCB
If the malfunctioning PCB has the 800K ROM installed, swap
them into the new PCB before installing it into the customer's
Macintosh.
NOTE: If the ROM were swapped from the "BAD" PCB to the "NEW"
PCB, remember to install the original ROM from the new service stock
PCB into the bad PCB before returning it to Apple.