It's an ER1400. I have a datasheet, there is no internal battery on that one. The Stamanns sell them and there is a note on their website saying to program them as detailed in the manuals. I didn't get it there though, their shop is currently closed. According to the NSM manuals, there is a default code of all zeroes to enter the program and a one-off option to change the code which MUST then be remembered. I had no idea whether the code had been changed which is why I went the route of replacing the ROM when I couldn't access the program. I have successfully altered the program on these in the past but I have never needed to do one from scratch. Typically the problem I was expecting was a location with a corrupt entry. There is actually very little wrong with this ES2 jukebox - if I attempt to access the program and abort it (ie toggle the cabinet switch), it then it will work fine until power off. There is a guy here in the UK who only does NSMs, I have messaged him so I will let you know what he responds. It is Easter weekend so it will likey be next week (hopefully). Norman.