Found an issue with Di2 6770 since it was taken of by main road bike. The connecting pin on the external battery mount was corroded so a new Battery mount was sourced.
When hooked up on the bench with a fully charged battery.
- Green light comes on the Front Junction box
- Button press gives the RD protection and cycles through all gears using FD and RD
- No response from either levers, to change gear
- Battery check doesn't work when lever held in for 0.5 sec
Switched to another Front junction box thinking it may be the cables, but exactly same symptoms.
Now thinking it may be due to the firmware on the battery mount (SM-BMR1) differing from the rest of the Di2.
Does this sound plausible, appreciate any input on this.