PM5 dead after some time sitting

[masc]

Hello,

I have an indoor rower from 2018 with a PM5 monitor.

Unfortunately, after sitting for some time, the monitor is not turning on. What I have tried:

- holding Units and Display buttons and pressing reset (nothing happens)
- changed the LR20 cells that came with the unit to newer VARTA Longlife ones
- the cells have a reading of 1.6V, tested with a multimeter
- the cable going into the unit outputs some voltage when the rower is in use, the voltage differs depending on the rowing speed#
- for a short moment after putting the batteries, the unit turned on, asking for date and time, then it worked for 5 minutes and after the auto-poweroff didnt turn on again

I am a little confused. The unit was working the last time I used the device and 225€ for a new one would be unfortunate.

How can I further dig into the problem?

Thanks in advance

[Citroen]

Have you tried powering it with a USB-B printer cable?
Plug the USB-A end into your laptop, plug the USB-B end into the bottom of the PM5.

[Carl Watts]

Make sure you use a set of brand new batteries not a set that has been lying about for years even if they measure okay.

When its working update it to the latest version of firmware.

Make sure the battery terminals are clean and shiny where it contacts the battery.

[Carl Watts]

Probably should add that just leave it overnight with no batteries then fit the new batteries.

I would be surprised if it didn't turn on.