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Di2 help - totally dead

by Jasonhenley
Wed, Mar 06, 2019 17:08
4

Hi

Need some help with my Di2 system 

Other day went to change gear (on Turbo Trainer) and it was like a dead battery. 

Tried charging up and was getting a small amount of charge but the front derallieur was clicking in sync with the amber charge light. 

Swapped battery with another bike thinking it was the battery and still the same. 

All cables have been unplugged and reseated. 

Changed 3port box and still the same. 

Tried connecting to PC and nothing. Tried a different charging unit and still the same. 

Mom totally stuck. 

I know it’s not the battery, charging unit or junction box. 

Any ideas?

its a 6870 with internal battery

thanks

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4 comments

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kil0ran | 5 years ago
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Would be very odd if it was junction B, that's just a bunch of connectors, no electronics/logic involved.

I've had similar with my old 6870 system, I resolved it buy unplugging everything from the battery (easy as mine was external) and plugging in each component separately and seeing if it powered/operated. Each of them was fine and when I cabled everything back up and plugged in to standard diagnostics (eTube) it all worked fine. 

As most of the brains of the system is in the battery that's always the place to start.

 

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Jasonhenley | 5 years ago
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Thanks for the replies 

Been looking over it all night and think I’ve found it. 

Also helped if I changed the USB cable to a better one as the charger unit now shows the Master Init can’t be found!

Unplugged the battery and plugged it directly into the junction A box (bypassing junction box b) and it came to life. 

So it is either the battery cable or Junction Box B. I’ve ordered a new box from Wiggle to hopefully see if this is causing it. 

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SellMatt | 5 years ago
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It may have gone into crash mode if you knocked the derallieur somehow, you cant use the rear derallieur but the front normally still works. 

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CXR94Di2 | 5 years ago
1 like

Have you the Shimano diagnostic box, PCE1  ?  Not the one that connects through the port charger BCR2.  Or you can unplug each item and see if the system comes alive.  Unplug front derailleur and one lever, if system comes alive its either the disconnected lever or front derailleur.  If its still dead plug the lever back in and disconnect the other and so on, to eliminate items.   If non of it works then you will need the diagnostic box to connect each item to check over and update firmware/reset

 

After that its checking over cables for damage/corrosion

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