well i personally have never fixed a arcade game little lone owned one or anything i am actually just looking at getting into this hobby of collecting and fixing i am only 16 years old tho but i think it would be a good learning lesson and a rewarding hobby ANYWAYS the most advice i can offer being a complete and total noob to the topic would be try replaceing all the roms/ram with fresh stuff if this doesnt solve the problem troubleshoot the monitor have you tried adjusting any pots on the monitor to see if this resolves anything? this sounds like a very weird issue indeed and since i am a complete and total noob to the hobby i have no clue this is the best advice i can give at this point but u could try asking around on klov or somthing if none of this fixes it if you have watched johns pacman cabaret restore videos i can remember/recall when he first got the game up and running in a playable state that he had ms pacman and pacman sprites glitched together due to overlapping roms or somthing so this may be a place to start? have you tried downloading a fresh set of frogger roms from a reliable source and burning them to the eprom things and putting them onto the pcb and loading it up? if you plan to go this route i recommend this site for any and every rom or emulator needs
https://www.emuparadise.me/M.A.M.E._-_Multiple_Arcade_Machine_Emulator_ROMs/Frogger/12989 i use this site all the time for mame roms to just play some games in mame for fun that link there is a link to a frogger rom as your issue is with a frogger i apologize if this doesnt resolve or fix anything
