You are watching a set of ALL the ROMs for a ARP PRO/DGX synthesizer. This synthesizer used 8 ROMs and is very common to find a synth like this without the ROMs as they are often "cannibalized" for these parts. You can buy all the ROMs or select only the one you need.
These parts are NEW and are tested in my own ARP PRO/DGX.
Contact if you need help or more information.
Board A (Waveform Generator)
Z15 - A2701-057-1
Board B (ADSR)
Z1 - A2701-057-2
Z2 - A2701-057-3
Z3 - A2701-057-4
Board C (VCF, VCA)
Z6 - A2701-057-5
Z7 - A2701-057-6
Z8 - A2701-057-7
Board D (Special Effects)
Z1 - A2701-057-8