E-mu SP-12 Diagnostic Debug Eprom
This is the Debug/Diagnostic eprom and released by E-mu Systems with the purpose of troubleshooting issues normally only issued to E-emu technicians. This debug tool requires one eprom chip.
The EPROM allows you to run a debug software, this can help you determine what IC or component that might gone bad. You can find videos on YouTube about the usage process for troubleshooting with this debug software and check also the picture with the different tests, which this debug eprom allows.
Open your E-Mu SP12 and swap the chip in IC 114, where chip A is currently sitting