check out the link below. been using the DATAQ DI_730 for years.
best troubleshooting tool hands down on the market.

it is an 8 channel analog to digital recording logger that hooks to any laptop. will continuously record for weeks or months depending on sampling rate. looks like a time stamped O SCOPE with 8 waveforms that anyone can operate on their laptop. make sure you
get the PRO version of the software. the best 4500.00 bucks you can spend. will record AC or DC from 5mv to 1000v on each channel. with a little time you can find all intermittent issues.

https://www.dataq.com/products/di-730/di-730-en.html