Powertap Joule 1.0 factory reset/troubleshooting

Hey

Forgot my normal use computer at a friend last week. While waiting to get that shipped back, pulled out an old powertap joule 1.0 for power readings.

Was working normally last ride 2 days ago, but decided to hook up to computer to download data file and change dashboard to 5-sec power averaging. Was normal immediately after disconnecting, but ~5-10 minutes later, noticed the display was much dimmer than typical. I can see appropriate dashboard readings if I hold it to my face, but otherwise, the display is too dim to read.

Does anyone remember dealing with this? Is there a setting I accidentally tinkered with? Or if there’s a factory reset I could try?
Firmware updated to no avail.

Thanks