Tacx flow - calibration error and power drop out

My Tacx Flow was working fine until 2 days ago, when it suddenly stopped calibrating. I can't get it to calibrate in either the Tacx app or with my Edge 1040. The Edge 1040 can't get a power signal. On the Tacx app, there's a power signal but it drops out intermittently, especially if I change gear or the power target changes. I do't lose reistance, although it will change, as if it thinks I'm pedalling too slow or too fast and needs to alter the resistance for my power target. This is making it super difficult to do my scheduled training and fitness tests (and is really hard on my knees).

There are lots of questions around cailbration, but I think this might be a power sensor transmission problem. Is there anything I can do to try to fix this? I have a subscription, which is pretty much money down the drain if my trainer isn't working.

  • Additional info: it seems to work fine with my Fenix, which reads even lower power with no dropout, which makes me wonder if it's a Bluetooth problem. Although I can't calibrate it with the Fenix. I don't think there's any way to get the trainer to talk to my Samsung phone using ANT, though, so I still can't use the Tacx app. I've even tried the demagnetising my chain with a fridge magnet trick.

  • Update: put in a call to Garmin support and very quickly got agreement to replace the unit after explaining everything I'd tried so far. (I don't think the magnet trick is common!) I suspect the power sensor connection to bluetooth is fubared in some way from the way it very suddenly stopped working. It has always had problems reconnecting if an activity auto-pauses, so maybe it has always been a bit dodgy.