I've been able to use the RS 232 interface to fetch traces and screen grabs from the unit. If you'd like the code (python scripts) I can share them with you.
Also, you might try checking/replacing BT150 on the A18 memory board. This might enable you to keep stored waveforms when powered off. My notes show the following for those:
- Lithium Poly-Carbon monoflouride, BR 2/3 A
- Potential part numbers Panasonic BR-2/3AE2P or BR-2/3AE2SP