New 7854 Replacement ROM Board Now Available
6-26-2025 Update
We are again offering these ROM boards for sale. See our 7854 Mostek MKB36000 ROM Repairs page for the latest information.
1-28-2024 Update
We have sold our inventory and have now discontinued this board.
We have some 1980's oscilloscopes at the museum which used the Mostek MKB36000 ROMs which are known to deteriorate over time (e.g. FROMs - Forgetful Read Only Memories). One is the Tektronix 7854 Oscilloscope with Digital Storage Oscilloscope. The ROM board contains four ROM sockets, a FPLA, and two EPROMs for patches (i.e. updates) to the masked ROMs. The FPLA "traps" addresses and the EPROMs supplies the new data.
The vintageTEK museum now offers a replacement ROM board. It was designed by one of our volunteers and is available on our eBay store.
Both the regular and diagnostic firmware are included, chosen by a top-accessible DIP switch. A keypad overlay for diagnostic mode is included.