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Di2 Toubleshooting: Any last suggestions?

chrisrwelchchrisrwelch Posts: 2
edited July 2020 in Workshop
Hi, all!

I’m in the process of building up a new bike with Shimano Ultegra R8070 Di2 and I've run into an issue that has stalled the assembly.

Problem: The left shifter switch-X (front upshift) intermittently works on brand new Ultegra 8070 equipment.

History: After accumulating all the components, all firmware was updated and everything was bench tested. All worked great (albeit with very little operation).

After routing and installing all of the components, I found the front upshift button (left shifter switch-X) was only working intermittently. By intermittently, I mean the button just doesn’t function for a period of time. I have yet to definitively isolate what is causing it not to work or what causes it to start working again.

On rechecking wire connections, recycling power to the whole system did not correct the issue. However, the connection between the downtube wire and junction box B seemed suspect as removing and reseating this connection would fix it temporarily. Both the downtube wire and junction box were replaced, but the problem returned.

Some Details:
• Battery is charged and the system has power.
• Recycling power does not fix.
• All firmware is up-to-date.
• All wire connections have been checked and re-checked. The downtube wire and junction box B have been replaced.
• The front derailleur upshifts just fine in full-synchro mode.
• The front derailleur upshifts just find when the upshift function is configured to another switch (such as switch-A on top of the hood or switch-Y).
• When switch-X is configured to something else (such as D-Fly Ch. 1) it will work intermittently.

My conclusion thus far:
Based on everything I’ve tried so far, I’m leaning toward a bad shifter that needs to be replaced under warranty. Any other suggestions before I pull that trigger?

Thanks in advance for any advice.


  • chrisrwelchchrisrwelch Posts: 2
    edited July 2020
  • tourdrivingtourdriving Posts: 227
    edited July 2020
    Here are the manuel for di2 system side no 9 for FD

    The settings to be adjusted are as follows.
    Item Description
    [Down] Moves the chain guide toward the inside (- display direction).
    [Up] Moves the chain guide toward the outside (+ display
    Displays the current set value in [Setting Value].
    * The front derailleur and the rear derailleur will not operate while this procedure is being
    carried out, even if you operate the shifting switches.
    * FD-6770 cannot be adjusted.
    * Rotate the crank arms while carrying out operations which are related to adjustment and
    gear shifting.

    6. Click [Set] to complete adjustment. bike hire and travel links, in 47 countries UK Bike & Motorcycle hire in Counties after ABC
  • cookie56cookie56 Posts: 19
    I would suggest you have done enough to isolate the issue with faulty shifter X button
    So think it is a warranty claim for sure
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