The device is a EEPROM, made by General Instruments, part number ER1400. This is a MOS device and runs at -35VDC (+/-8%) relative to the chip's common. Not your normal Eprom!
Serial RAM...not a ROM or PROM.
You can find the data sheet online under the part number easily enough!
John :-#)#
On 2025-04-18 11:29 a.m., Andrew Burkhart via Jukebox-list wrote:
What is the chip make/model? I have a chip programmer (an old Needham's unit) and was able to read / save / and program ROM chips of specific sizes. I may have spare chips, depending on what is being used. I may also have an older IR unit, but I'm not as familiar with that one.
Andrew Burkhart
-----Original Message----- From: Tony Miklos via Jukebox-list jukebox-list@lists.netlojix.com Sent: Thursday, April 17, 2025 4:46 PM To: NORMAN MACRAE nmacrae23@btinternet.com; Jukebox mailing list jukebox-list@lists.netlojix.com Cc: Tony Miklos tonysjukeboxrepair@gmail.com Subject: [Jukebox-list] Re: NSM EA ROM Programming
On 4/17/2025 3:17 PM, NORMAN MACRAE wrote:
Hi Tony Milos,
About twenty months ago you posted about an NSM ES2 where you were having difficulty programming the EA ROM - did you ever resolve that?
I am working on a City2 where I cannot access the program. I thought it may have been set with a secret code so I got another EA ROM but I still cannot access the program.
Thanks in advance for any insight, Norman.
I never found anyone who programs them. I believe they have an internal battery and even if they are NOS, they are due to fail at any time. If there is a big enough call for it, someone might figure out how to program a newer IC and make it work, but it doesn't look like anyone has much interest in the task. I'm turning down jobs on them now. They are turning into big paper weights. Good luck, let me know if you ever find a solution.