Hi
When you power your unit on, do you have the error led lit on and a 4 displayed on these two modules? If so, it simply means the inside battery must be replaced, an easy task if you know how to use a soldering iron. I've got two TX816, both have modules with the same issue. My advice is to purchase holders for a CR2032 battery; by bending the legs a little bit, it fits the holes of the current battery.
I've already did this on a couple of modules. When I'll get some spare time, I'll replace all batteries on all the remaining modules.
HTH,
Fran?ois
alesisfusion8hd