HP Infiniium Series Atlas III Motherboard (Oldest generation Infinium oscilloscopes still branded as HP):

• [RTC. There’s no exposed batteries] bq3287AMT = DS1288

Tektronix TDS Series (500, 600, 700, 800)

• Older TDS (without alphabet suffix): Dallas DS1245Y
• Model number that ends with ‘A’:  Dallas DS1650Y

The NVRAM in TDS series only contains the options data. Since I can reprogram the options, I can start with a blank NVRAM without reprogramming it). 

Will keep updating this page when I came across more test equipment.