Eprom M27C256B-10F1. 32Kb x 8 super-fast 100ns 28pin. 12 volt programming. Device ID: 20 8D.
These were purchased in China. All tested good on a Xgecu Pro TL866II+ eprom programmer for Pin Test and Blank Check capabilities. See the pics below.
We can program your eprom for a small fee. Just hit the Ask a Question Button on this item. We have many binary files going all the way back to the 1970's - arcades, jukeboxes, pinballs and slot machines. Or send us your binary file.