Di2 confusion

[TheTriFatlete]

Hi all, I am scratching my head with a Di2 set-up.

I purchased a secondhand groupset for my girlfriend and fitted it all to the bike. I plugged the charger in and no light, so I assumed the (older style) battery was kaput, so I bought a new one. Still no charging light.
Tested the charger on my system, it worked, so systematically tried junction boxes and wires and still nothing. Tried my battery, nothing. At some point, I had the RD unplugged and I noticed the FD worked. Plug the RD back in and the whole system is dead. Unplug and FD works.
Wondered if the RD was in crash mode but holding the button didn't work, so I'm thinking I have a duff RD. I take the RD off my TT bike, so I can get Katherine's bike running and nothing, the system is dead. As a test, I unplug the FD and the RD works. Plug in FD and the system is dead.

What is going on, please? Both derailleurs work but only if one of them is plugged into the system. Have the both plugged in and it seems to kill the whole system.

Thanks in advance.

 

[avsd]

Tried downloading and running the e-tubes software from the Shimano website. It might give you some diagnostic information to post here. Have you any spare Di2 cables to swap onto the bike?

 

[TheTriFatlete]

I have tried a variety of cables and it all still works with just the one derailleur. It just doesn't like two!

 

[IanSmithCSE]

Good morning,

Just a thought, can you check the model numbers of the front and rear mechs and are they the same series?

Are you aware that Shimano deliberately disabled the mixing of 10 and 11 speed parts not long after 11 speed was introduced? This would reflect your description of both mechs working stand alone but not as a pair.

I am not sure if you can mix and match pre and post this change 11 speed front and rear mechs though.

Bye

Ian

 

[jowwy]

Hi all, I am scratching my head with a Di2 set-up.

I purchased a secondhand groupset for my girlfriend and fitted it all to the bike. I plugged the charger in and no light, so I assumed the (older style) battery was kaput, so I bought a new one. Still no charging light.
Tested the charger on my system, it worked, so systematically tried junction boxes and wires and still nothing. Tried my battery, nothing. At some point, I had the RD unplugged and I noticed the FD worked. Plug the RD back in and the whole system is dead. Unplug and FD works.
Wondered if the RD was in crash mode but holding the button didn't work, so I'm thinking I have a duff RD. I take the RD off my TT bike, so I can get Katherine's bike running and nothing, the system is dead. As a test, I unplug the FD and the RD works. Plug in FD and the system is dead.

What is going on, please? Both derailleurs work but only if one of them is plugged into the system. Have the both plugged in and it seems to kill the whole system.

Thanks in advance.

are both derauillers of the same make and model??.....some di2 RD and FD are not compatible

 

[TheTriFatlete]

Ian and Jowwy,

Thank you, that could be the problem. The RD is 6870, the FD is 6770. I didn't realise that they were not compatible, having been told that the 6770 shifters would operate a 6870 RD.

Thanks.

 

[Joffey]

Have you got the wifi module? That can break and sent things into a spin.

I know from personal experience that Di2 is very tetchy. If one of the wires is slightly damaged it can fail. It might be a case of ripping out all the wires, checking each one and reinstalling them all.

Another idea is phone up a Shimano Service Centre - they might have come across that before and might know the quicker fix.

I phoned York Cycleworks - if you are not from that region though there will be one close to you just in case you need to take it in.

 

[TheTriFatlete]

York Cycleworks are the best bike shop in York.

I have found something online that says 6870/6770 mechs cannot be run together in the same system, so I have ordered another FD.

 

[JoeyB]

As others have said, can you confirm the model of shifters, FD and RD you have fitted?

It does sound like you have a 10/11spd compatibility issue from what I've read so far. Whilst mixing them is possible it is reliant on specific firmware versions being in place on specific components. If everything is now running the latest firmware then you may be up chocolate creek with the current setup.

Have a read here: http://carltonbale.com/shimano-di2-everything-you-need-to-know/#compatibility