8085 Dissasembly?

Hi friends. I have a 1990's vintage commercial radio system that uses an 80C85A CPU. I am looking to hopefully modify the firmware to make some small changes in its behavior. The firmware is contained in two EPROMS. Can anyone recommend a decent disassembler to use with this? Preferably something that ran in windows 10 or windows 7? A dos box would be fine too. Also, I looked through the dumped contents of the EPROM. In the past I have seen EPROM ascii dumps where most is unintelligible to the naked eye but typically text messages give to the users during interaction with the program are human readable. In this case, the ASCII dump shows only other HEX data. I believe I read that there is a HEX format and that I might need to convert from HEX to BIN before disassembling. Of course, an ideal tool would do both if anyone knows such a thing. I am not familiar with 8085 stuff but any insight would be appreciated. Lastly, I wonder if there might be some kind of checksum check to prevent tampering. Is there a common way this is handled in 8085 world? Or is it entirely programmer dependent? Thanks for your time Eugene W2HX?