Sorry to start another answer, but I wanted to add to what we've been talking about. I found a data sheet for one of the Microchip products that looks interesting.
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[link|http://ww1.microchip.com/downloads/en/DeviceDoc/22067J.pdf|11AAXXX/11LCXXX Data Sheet|new_window=true]
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[link|http://ww1.microchip.com/downloads/en/DeviceDoc/22067J.pdf|11AAXXX/11LCXXX Data Sheet]
When I scrolled down the the package marking section, guess what I found?
[image|2782015]
According to that, the first two characters, B2 designate the part, and the last two are some sort of "Alphanumeric traceability code". B2 corresponds to part number 11AA020 that's referred to on the Mouser site as EEPROM 2K 256X8 1.8V SERIAL EE IND.
So if that's the right part, you should see 1.8V across pins 2 and 3. I'd power up the good board you have and stick a voltmeter on there and see what you get.
[image|2782030]
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EDIT: Actually, according to the data sheet, that part can run with a wide voltage range, anywhere from 1.8-5.5V.
Hi John,
Sorry to start another answer, but I wanted to add to what we've been talking about. I found a data sheet for one of the Microchip products that looks interesting.
[link|http://ww1.microchip.com/downloads/en/DeviceDoc/22067J.pdf|11AAXXX/11LCXXX Data Sheet|new_window=true]
When I scrolled down the the package marking section, guess what I found?
[image|2782015]
According to that, the first two characters, B2 designate the part, and the last two are some sort of "Alphanumeric traceability code". B2 corresponds to part number 11AA020 that's referred to on the Mouser site as EEPROM 2K 256X8 1.8V SERIAL EE IND.
[link|https://www.mouser.com/ProductDetail/Microchip-Technology/11AA020T-I-TT?qs=Xb8IjHhkxj4T%252BhkPpUuHMA%3D%3D|11AA020T-I/TT Microchip Technology|new_window=true]
So if that's the right part, you should see 1.8V across pins 2 and 3. I'd power up the good board you have and stick a voltmeter on there and see what you get.
[image|2782030]