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Discussion Starter · #1 · (Edited)
Look over the word "in" at the bottom at the spot on the black wire where the exposed copper is showing.

Could this be why my crank sensor displays a flashing "RPM" as normal, but displays "zero" instead of the cadence?
 

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It's possible, even likely, if the wire is coaxial and the shield is used in transmitting cadence. It's not possible if the wire is dual-stranded, like speaker wire. Some computers use coaxial, others dual-stranded computer wire.
 

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Discussion Starter · #4 ·
wim said:
It's possible, even likely, if the wire is coaxial and the shield is used in transmitting cadence. It's not possible if the wire is dual-stranded, like speaker wire. Some computers use coaxial, others dual-stranded computer wire.
How can electronic-stupid me tell if it's coaxial or dual-stranded?

FWIW, it appears to be 2 parallel wires coming from the computer itself, which divide further on down to the crank sensor & speed sensor.
 

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Discussion Starter · #5 ·
PJ352 said:
What brand/ model bike computer is it?
It's a Cateye Astrale 8.

A friend gave it to me for Christmas, so I'll cry if I have to throw it out.:cryin: :cryin:
 

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I'm almost certain the two wires of the cadence Astrale are coax wires, even though they look paired before they split into cadence and speed. Coax repairing is not easy, but it's been done (not by me). Recumbent riders splice an extra piece into these wires sometimes because the stock wires aren't long enough. Perhaps one of them will post some instructions (no requirement to admit to 'bent ownership :D)
 

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wim said:
I'm almost certain the two wires of the cadence Astrale are coax wires, even though they look paired before they split into cadence and speed. Coax repairing is not easy, but it's been done (not by me). Recumbent riders splice an extra piece into these wires sometimes because the stock wires aren't long enough. Perhaps one of them will post some instructions (no requirement to admit to 'bent ownership :D)
Exactly right, wim. I have the Astrale 8 and have easily repaired breaks in the single wire, but not the paired areas.

If the OP is not certain there's an actual break in the wire, I'd double check the distance between magnet and sensor. They need to be VERY close (2 mm's?) to be functional, especially the cadence sensor. I say this because I'm doubting that an exposed/ bare (unbroken) wire would cause such a failure.
 

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Discussion Starter · #8 ·
PJ352 said:
If the OP is not certain there's an actual break in the wire, I'd double check the distance between magnet and sensor. They need to be VERY close (2 mm's?) to be functional, especially the cadence sensor. I say this because I'm doubting that an exposed/ bare (unbroken) wire would cause such a failure.
PJ, Wim, I appreciate the advice.

The distance between magnet & sensor was checked, and at 1(?)mm- closer than what worked before, anyway-, still no reading comes up, just a flashing 'RPM' like before.

3 other FWIW's:
A) Speed registers fine.
B) Not sure if this helps isolate anything, but I placed my finger over the exposed wire while spinning the crank, and that didn't help.
C) This happened shortly after I returned a rental car. The way I had the bike in the rental may have had the wire rubbing against something. Not 100% on that, since I think it was working right after leaving the rental place.
 

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Another thought

lx93 said:
PJ, Wim, I appreciate the advice.

The distance between magnet & sensor was checked, and at 1(?)mm- closer than what worked before, anyway-, still no reading comes up, just a flashing 'RPM' like before.

3 other FWIW's:
A) Speed registers fine.
B) Not sure if this helps isolate anything, but I placed my finger over the exposed wire while spinning the crank, and that didn't help.
C) This happened shortly after I returned a rental car. The way I had the bike in the rental may have had the wire rubbing against something. Not 100% on that, since I think it was working right after leaving the rental place.
If you haven't already, try this: remove the computer from its mount and clean all the contacts on it and the mount. Reinstall making sure the unit clicks in place and see if that works.

If it doesn't, another option (and you'll lose ALL your data if you do this) is to press the AC (all clear) button behind the unit. This will remedy the problem only if the unit needs to be reset, so make sure it's worth it to you before proceeding.

I did notice in the instructions that if the speed OR cadence don't register, there may be a short circuit in the bracket and/ or sensors. They don't say so, but I'm assuming in that case that assembly (not the computer itself) needs to be replaced. Performancebike - $20.
 
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