PT transmission diagnosis?

waterrockets said:

PT SL, wired: cadence and HR work, but no data from hub. I get no speed reading in cyclocomputer mode with a magnet. Hub batteries test at 1.57V each. Brand new Cervo battery.

Should I even bother with new hub batteries? This is looking like a harness problem -- I thnk I can find a harness to try my Cervo and hub out on.

Thoughts? Looking for the most efficient route to a diagnosis so I can get it fixed ASAP.

Thanks!

make sure the sharkfin is mounted very close to the hub...that solved my problem of lots of dropouts. It sounds like your's is something different. Get another PT bike and back up the sharkfin close to the hub and see if it picks it up.

mr_mojo said:

make sure the sharkfin is mounted very close to the hub...that solved my problem of lots of dropouts. It sounds like your's is something different. Get another PT bike and back up the sharkfin close to the hub and see if it picks it up.

Yeah, I guess I should have said that I've been using this PT flawlessly for ~3 weeks, and did not change the setup. I did bring the wheel into my shop to bump up the tension a bit, but I don't see how that could have changed anything -- still no worky when I put it back on...

Ok, tried it with a different harness, same hub and Cervo, and everything worked great.

waterrockets said:

Ok, tried it with a different harness, same hub and Cervo, and everything worked great.

Did you use zip ties on the harness wiring?

serpico7 said:

Did you use zip ties on the harness wiring?

Initially, but I changed to tape on the 2nd day 😉

There's a chance I hosed it on that day though. Strangely, the orginal harness is working happily now.

I'm having the same problem with the PT I just got yesterday. It worked for about 30 seconds total. 😠 No power or speed readings, just "----". Saris is sending me a new harness and sensor. I really hope thats the problem because I waited two months for this hub.

strader said:

I'm having the same problem with the PT I just got yesterday. It worked for about 30 seconds total. 😠 No power or speed readings, just "----". Saris is sending me a new harness and sensor. I really hope thats the problem because I waited two months for this hub.

Man, that blows. I feel your pain.

I imagine Saris may have gone through all this with you already, but just in case:

Have you tried it with the harness completely off the bike? Just set the harness on a table with the computer mounted, and set your wheel on the table above the shark fin. Spin the axle with your fingertips, and it should transmit. Mine was failing this test, but has since begun working.

Another thing to try is the magnet in another rear wheel, then set the Cervo to "cycle computer" mode (display cadence: "C," hold "SELECT" for 2s until "WATTS" vanishes). The shark fin should pick up a magnet for speed readings. If the harness is off the bike, you can just swing a magnet past the shark fin every 1/2 second or so. This test may tell you that the harness is ok, or confirm that it's hosed.

I just tried the magnet trick you suggested to see if it would work in cyclocomputer mode, and didn't get a reading. Hopefully that means it is the harness.
After I read about the zip ties causing problems for some people, I cut all the ties I was using and attached the wire only with tape. I'm wondering if the cable might be sheared internally.

waterrockets said:

Initially, but I changed to tape on the 2nd day 😉

There's a chance I hosed it on that day though. Strangely, the orginal harness is working happily now.

So the harness is working, the hub is working, the head unit is working. I would guess the initial problem was caused by the harness - maybe inspect the wires very carefully.