debug EPROM for the Emulator ITHE This operation system update/upgrade requires two eprom chips as revealed in the eBay article`s photos + one debugging chips OS 3.1 is the last OS upgrade released by E-MU for the EII. Upgrading to OS 3.1 will improve following: Improve Macintosh communication on very early machines The debug EPROM allows you to run software diagnostics via the RS232 port on the back of the emulator. Scanner v3.1 < IC-socket located at IC 28 Main v2.1 < IC socket located at IC 42 DEBUG eprom < IC-socket located at IC 42 LOWER SHIPPING COSTS FOR MULTIPLE PURCHASES When buying more items, do NOT use the eBay checkout, it could calculate the shipping costs too high. When you are finished shopping, use eBay's "ask the seller for total" function. Mark as Favorite Seller t