Shimano hub dynamo stopped working

For discussions about bikes and equipment.
Post Reply
Stroud Active
Posts: 24
Joined: 11 Jul 2020, 3:53pm

Shimano hub dynamo stopped working

Post by Stroud Active »

I've got a Shimano DH-3D37 front hub dynamo. It stopped working last week. On one ride it worked fine, on the next ride there was nothing. I measured the output using a multimeter and it couldn't detect any consistent voltage. I was expecting 6v AC. I took it apart and couldn't find anything obvious wrong. Upon reassembly and testing I found that the two terminals had continuity between them and still no voltage when the wheel was rotated. I might have damaged the positive wire during reassembly or it might have been the original issue, I'm not sure.

I noticed that there's a lot of internal assemblies for sale online so I'm guessing that issues can occur with these. Is buying a replacement hub the best option?

Availability of the internal assembly is limited so I'm considering buying a DH-3D37-QR 104 mm (quick release) version and swapping all the parts over or putting a QR skewer through it to replace the end nut shaft I currently have.

Are any of the other internal parts interchangeable? From another thread:
DH-3N30 et al - copper windings, utility grade
DH-3D37 et al - alu windings, utility grade
DH-3N72 et al - copper windings, sport series
DH-3N80 et al - alu windings, sport series
Jdsk
Posts: 24640
Joined: 5 Mar 2019, 5:42pm

Re: Shimano hub dynamo stopped working

Post by Jdsk »

Have you found:

"Servicing a Shimano Dynamo Hub"
viewtopic.php?f=5&t=117634

Jonathan
User avatar
ConRAD
Posts: 761
Joined: 20 May 2010, 10:55am

Re: Shimano hub dynamo stopped working

Post by ConRAD »

Stroud Active wrote: 16 May 2021, 4:11pm... upon reassembly and testing I found that the two terminals had continuity between them ...
... between terminals you should measure something like 3.5 Ohm

Image
Image
Stroud Active
Posts: 24
Joined: 11 Jul 2020, 3:53pm

Re: Shimano hub dynamo stopped working

Post by Stroud Active »

Yes, I came to realise that the resistance of the coils is low enough to be regarded as continuity. The good news is that the hub still works fine.
Post Reply