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Di2 rear derailleur giving me nothing but problems

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Di2 rear derailleur giving me nothing but problems

Old 07-21-19, 07:32 PM
  #1  
misterwaterfall
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Di2 rear derailleur giving me nothing but problems

I let my bike sit for a while, and now that I知 back on the horse I知 having issues with my rear derailleur. So far I致e replaced the shifter, junction box, and all cables. Where I知 at:
The junction box shows a battery level light when the right shifter is held down, so the shifter is working.
The rear derailleur did attempt to activate when I plugged in the new shifter, but when the shifter buttons are pressed all I hear is a faint click and no actual shifting takes place.
Im not able to get it to go through the crash reboot. When I hold down the button on the junction box it値l go solid red, but I can稚 get it to flash and go through the crash reboot process.
I attempted to move the derailleur by hand and it didnt want to budge. Not sure if this is good or bad.

im really at a loss here. Any advice before I give up and pay a shop to fix it for me?
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Old 07-21-19, 09:10 PM
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sch
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DO NOT try to move either derailler 'by hand'. You risk breaking linkages internally causing fatal demise of the
innards. I once thought I had a major system failure, but it turned out to be failure to fully insert the cable jack
into the socket. This despite repeatedly, using the Shimano tool putting 'lots' of pressure on the jack and gently
tugging to make sure it was seated, but it was not. Since you have replaced everything but the RD, the last
other option is to remove RD, find a friend with Di2, pop their cable out and plug it into your RD and see if it
shifts. Absent that your best third option is a shop with a Di2 guru and an the requisite computer/software/
interface to assess the system. My local dealer says 98% of the time in his experience Di2 'fails' are incompletely
plugged in cables.
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Old 07-21-19, 09:35 PM
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Cyclist0108
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Mine has been problem-free for five years. What you have is not normal, so I would definitely suggest taking it to a competent shop, and if it is under warranty, possibly pursue a warranty claim.
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Old 07-22-19, 08:45 AM
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misterwaterfall
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Originally Posted by sch
DO NOT try to move either derailler 'by hand'. You risk breaking linkages internally causing fatal demise of the
innards. I once thought I had a major system failure, but it turned out to be failure to fully insert the cable jack
into the socket. This despite repeatedly, using the Shimano tool putting 'lots' of pressure on the jack and gently
tugging to make sure it was seated, but it was not. Since you have replaced everything but the RD, the last
other option is to remove RD, find a friend with Di2, pop their cable out and plug it into your RD and see if it
shifts. Absent that your best third option is a shop with a Di2 guru and an the requisite computer/software/
interface to assess the system. My local dealer says 98% of the time in his experience Di2 'fails' are incompletely
plugged in cables.
Thanks for the help. All cables are plugged in properly but from the sounds of it my derailleur might be fried. It attempts to shift but only puts out a faint clicking which means that it's getting signal and attempting to do something, but it can't do that something properly. The search for a used 10 speed derailleur will be fun Im sure
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Old 07-22-19, 01:24 PM
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sch
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OTOH, if the 10spd RD turns out to be toast, it is 'relatively' inexpensive to go to 11 spd. New RD/FD and cassette
and that is all you need. The brifters and chainrings and oddly IME chain all don't care. The cables and A/B boxes
also don't care. If you get a GS RD you can go to 11-34 and probably 11-36 cassettes (some have posted positive
shifting on 11-36 with an unmoded GS, but wolftooth type extenders are $6-10 on amazon). But I am thinking of
my experience with 6870 GS, the 8000 series Di-2 has a greater intrinsic range than the 6870. I have a spare 10spd
RD for my recumbent which is where the original 10spd 6770 RD went. It is NFS.
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Old 07-23-19, 03:13 PM
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Originally Posted by misterwaterfall
Where I’m at:
The junction box shows a battery level light when the right shifter is held down, so the shifter is working.
The rear derailleur did attempt to activate when I plugged in the new shifter, but when the shifter buttons are pressed all I hear is a faint click and no actual shifting takes place.
I had a Di2 11sp RD fail on me earlier this season with the exact symptoms you're having (mine had 12,500 hard miles on it). It's toast. Bring $280 to your LBS and get another one installed.

Last edited by Riveting; 07-23-19 at 03:18 PM.
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