After years of trusty service my HP54601A scope died. Actually he didn’t die, he started to complain about it’s memory on power up. That made him useless. So time to unscrew the backside and see what’s inside.

This scope is well build and easy to dismantle. One large PCB on the bottom is all there is and you’ll directly spot the two types of memory used, a EPROM containing the main CPU software and a DS1220 (Dallas 16k Nonvolatile SRAM) to store settings. I trust the EPROM and don’t trust the DS1220 so much. The first line on the datasheet states “10 years minimum data retention in the absence of external power” and this scope is about 15 years old so I’ll start by blaming the DS1220.
Read on …