Strange issue with Di2 7971

Grill
Grill Posts: 5,610
edited May 2018 in Workshop
I'm having a really weird problem with the Di2 on my Plasma.
I just replaced the wiring harness for the aero bar and bull horn shifters and everything was working fine, but recently the bar end shifter for the rear mech stopped upshifting. It still downshifts which means the wire hasn't been snipped and I plugged in the other bar end shifter which has the same issue so the issue is not with the shifter itself.
My mechanic is baffled over this as well and I was wondering if anyone else has had this issue or has any suggestions on how to resolve it.
English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg

Comments

  • Bar Shaker
    Bar Shaker Posts: 2,313
    Grill have you plugged it into eTube?

    It might have defaulted to a programming for an upshift button and a down shift button and your bar end shifter is acting as only the downshift.

    eTube will left you allocate new functions to any shift switches that you have added.
    Boardman Elite SLR 9.2S
    Boardman FS Pro
  • slowbike
    slowbike Posts: 8,498
    If eTube is reporting that it's set correctly and just not working then assign a different function to the malfunctioning button and see if that then works. If it does then change it back and test again.


    I've no knowledge of Di2 - just computers in general! ;)
  • Grill
    Grill Posts: 5,610
    7970 is pre etube...
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Essex Rouleur
    Essex Rouleur Posts: 98
    It might need updating via the eTube software. I had this problem with a climbing shifter. I plugged it in and only one button worked, and thought it was dodgy but the system wasnt updated to accept anything else being plugged into it being pre-eTube and hadnt been updated at all since its release.

    Once i hooked it into an eTube laptop and updated everything it all worked fine. Just a word of caution though, if your system hasnt been updated at all then make sure you update the battery option first, then do all the shifters.
  • Grill
    Grill Posts: 5,610
    Although I appreciate those trying to help, this is 7970 we're talking about. 7970 is the old 4 wire design, not eTubes. The first eTubes Di2 was 6770.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Matthewfalle
    Matthewfalle Posts: 17,380
    Get shot of it and buy mechanical. Maybe some nice Red. But I bet that wasn't the answer you wanted........
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • Grill
    Grill Posts: 5,610
    Actually that's a terrible solution considering that my frameset is Di2 only. Plus once you go electronic on a TT bike, you never go back...
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Essex Rouleur
    Essex Rouleur Posts: 98
    Grill wrote:
    Although I appreciate those trying to help, this is 7970 we're talking about. 7970 is the old 4 wire design, not eTubes. The first eTubes Di2 was 6770.

    Ok good luck with it.
  • NewTTer
    NewTTer Posts: 463
    Grill Shimano did make a diagnostic unit for the early Di2 (7970), I would suggest sourcing a LBS that has one and getting it checked that way. This type of fault will drive you batty otherwise
  • Grill
    Grill Posts: 5,610
    Cheers, I'll try to find somewhere local to me that has one.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • NewTTer
    NewTTer Posts: 463
    Grill wrote:
    Cheers, I'll try to find somewhere local to me that has one.
    Take a look at the link below, it is for an old ebay ad, but it shows you what I am referring to.

    http://www.ebay.de/itm/Shimano-Dura-Ace ... 1139940073
  • Bar Shaker
    Bar Shaker Posts: 2,313
    Madison may be able to let you know which LBSs bought them.
    Boardman Elite SLR 9.2S
    Boardman FS Pro
  • Ingallinas
    Ingallinas Posts: 1
    Has anyone else encountered this issue? My di2 Dura Ace 7970 rear derailleur has experienced the exact same symptom as OP. I let the battery drained but was able to recharge it fully. Now my rear derailleur would not shift up nor can I adjust it up while in adjustment mode. Shifting down works fine. When I hold down the adjustment button to activate crash mode recovery, it would successfully cycle UP and DOWN through all of the gears. I do see a solid green LED when shifting up so I know that the signal is being sent. To eliminate possible wiring issues, I swap the front and the rear derailleur connections and was able to use the right shifter on the front but the left shifter would not shift the rear up.

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