Polar Power and cadence falure

[TimBuch]

I have used the Polar Power system for about 3 months without any real problems, that was untill the power and cadence readings just vanished??? The speed readings are still there. In the past all it took was a quick fiddle with the magnet position and all was well. This time the Yellow and Green intermal lights seem to be dead. An expensive mail back and forward to polar resulted it being told the unit tested "OK"????? Does anyone know how to fix this before it ends up in land fill somwhere and I make SRM a little richer?

 

[beerco]

I have used the Polar Power system for about 3 months without any real problems, that was untill the power and cadence readings just vanished??? The speed readings are still there. In the past all it took was a quick fiddle with the magnet position and all was well. This time the Yellow and Green intermal lights seem to be dead. An expensive mail back and forward to polar resulted it being told the unit tested "OK"????? Does anyone know how to fix this before it ends up in land fill somwhere and I make SRM a little richer?

Did you try a new battery?

 

[mloywhite]

Occasionally, my cadence and speed disappear, and I found it is the connection between the back of the watch and the handlebar mount. I move it around slightly and it comes back. If I have it strapped down too tightly it is more likely to happen. Snug works better than really tight. Hope that helps.

 

[WarrenG]

I have used the Polar Power system for about 3 months without any real problems, that was untill the power and cadence readings just vanished??? The speed readings are still there. In the past all it took was a quick fiddle with the magnet position and all was well. This time the Yellow and Green intermal lights seem to be dead. An expensive mail back and forward to polar resulted it being told the unit tested "OK"????? Does anyone know how to fix this before it ends up in land fill somwhere and I make SRM a little richer?

If the cadence magnet is not aligned properly with the sensor you won't get cadence or power. So, get the cadence right and you should get power too. I use a stronger magnet that I got from Radio Shack, neodynium, and tape that to my crank arm, or add the neodynium magnet to the one included with the powermeter.

You can test the sensor function by passing a magnet right over the little mark on the sensor cover. If that works then it's just a matter of getting your crankarm magnet to do the same.

 

[vio765]

Occasionally, my cadence and speed disappear, and I found it is the connection between the back of the watch and the handlebar mount. I move it around slightly and it comes back. If I have it strapped down too tightly it is more likely to happen. Snug works better than really tight. Hope that helps.

i have had this issue before with cadence and speed disappearing. i have made the connection between the watch and the handlebar mount tighter. seemes to have worked for the past few days.

 

[TimBuch]

Did you try a new battery?

YES, a few times

 

[TimBuch]

If the cadence magnet is not aligned properly with the sensor you won't get cadence or power. So, get the cadence right and you should get power too. I use a stronger magnet that I got from Radio Shack, neodynium, and tape that to my crank arm, or add the neodynium magnet to the one included with the powermeter.

You can test the sensor function by passing a magnet right over the little mark on the sensor cover. If that works then it's just a matter of getting your crankarm magnet to do the same.

I have tried diffrent magnets in all positions, I even get the tiny ticking sound from the unit when the magnet passes but still no luck.

 

[TimBuch]

i have had this issue before with cadence and speed disappearing. i have made the connection between the watch and the handlebar mount tighter. seemes to have worked for the past few days.

No joy, I had tried this before. Did you say that you have lost power and cadence only in the last few days? I'm keen to see if this grows into a more common problem over the next few weeks. If so keep me posted.

 

[WarrenG]

I have tried diffrent magnets in all positions, I even get the tiny ticking sound from the unit when the magnet passes but still no luck.

That ticking sound is the reed switch inside the sensor. If that's ticking the switch is working and being activated. If the speed is displaying, other than checking to make sure you have cadence and power turned on in the watch/handlebar unit and having a fresh battery in the handlebar mount... I dunno. I once had problems because the cover for the battery in the handlebar unit wasn't latched exactly right to make all the contacts to the battery.

 

[TimBuch]

If the cadence magnet is not aligned properly with the sensor you won't get cadence or power. So, get the cadence right and you should get power too. I use a stronger magnet that I got from Radio Shack, neodynium, and tape that to my crank arm, or add the neodynium magnet to the one included with the powermeter.

You can test the sensor function by passing a magnet right over the little mark on the sensor cover. If that works then it's just a matter of getting your crankarm magnet to do the same.

I have just tried some small Rare earth magnets. The green light is now flicking but still no cadence. This is the case when I flick the magnet up and down with my hand as well. These are strong magnets and thay tend to throw the chain a little. If it comes down to a power reading against throwing the chain off over the top of a climb I would rather hang onto the bunch than stare at the zero reading as I get my hands covered in chain oil.

Thanks for the advice

 

[TimBuch]

That ticking sound is the reed switch inside the sensor. If that's ticking the switch is working and being activated. If the speed is displaying, other than checking to make sure you have cadence and power turned on in the watch/handlebar unit and having a fresh battery in the handlebar mount... I dunno. I once had problems because the cover for the battery in the handlebar unit wasn't latched exactly right to make all the contacts to the battery.

Yeah thay are swiched on, I have a small colection of diffrent batterys I have tried over the past few days. I think the battery is fine due to the fact that I still get speed and now get a gerrn light after using stronger magnets. However I'm no better of.

Tanks for your help

 

[beerco]

YES, a few times

I one time had mine quit after a washing. Given a chance to dry out they started working.

I should note that ultimately I sold my polar after 2 years and bought a used powertap. It was a good decision.

 

[TimBuch]

I one time had mine quit after a washing. Given a chance to dry out they started working.

I should note that ultimately I sold my polar after 2 years and bought a used powertap. It was a good decision.

I think it's to sensitive to bounce about on a bike. If thats the case the entire system must only have a very short life span. I am very interested in how many other people have had the polar system slowly fail to work after about 3 months.

 

[WarrenG]

I think it's to sensitive to bounce about on a bike. If thats the case the entire system must only have a very short life span. I am very interested in how many other people have had the polar system slowly fail to work after about 3 months.

I had two that lasted about 6-9 months each, but my third one has lasted well over a year so far. I bought the original at Performance Bike so if, and when it fails it goes back to them and they just replace it. No waiting for a repair from Polar.

 

[squidwranglr]

I am very interested in how many other people have had the polar system slowly fail to work after about 3 months.

I've been using mine for about a year and a half. I bought it used on eBay with about six months of previous life on it. Other than having to replace the cradle battery once, it has worked very well for me, besides having to use a different magnet on the crank and the known issues with accuracy on trainers.

Berend

 

[RoadBikeGuy]

I am very interested in how many other people have had the polar system slowly fail to work after about 3 months.

I've got 2 1/2 seasons of use from my Polar Power unit so far. The only problem was the battery dying once in it. I did pick it up used so it is at least 3 years old now. In fact after the initial mounting - which was a pain in the **** - things have been working fine without any problems for me.

 

[Bloggy]

A little back ground first.

This is just in case anyone was watchin this thread to see how it goes. I have taken TimBuch's polar for testing. (I'm his Bro)

Basically after a short ride I noticed that his fault had appeared. I also noticed that the power readings dropped off at the same time that the cadence dropped out.
After a little fiddling with magnets I found that the cadence reed switch, even though it was clicking (ie apparently closing when the magnet was near), was not reading the magnet coming around correctly. Timbuch had sent it back to Polar previously and they had given the reply of no fault found.

Now I'm not suggesting that any one tries this next part with their's because it is a bugger of a job to get done and would probably void your warranty (that is if Polar will warrant it ).

I took the Power and cadence sensor unit apart and tested the reed switch with a multimeter. I found that there was about 2.8 Volts over the reed switch. Which is good by the way. I then tested with the magnet near and still found that the 2.8V was present. This is bad becasue it means that the reed switch is not closing. I then tested by shorting the reed switch with a piece of wire momentarily and hey presto the little green light flashed. ***Note that holding the wire on for a long period of time will not help because the sensor circuit is only looking for a momentary voltage spike. A longer closure would probably cause a fault in the sensor logic and it would discard the measurement as an anomoly.

So I went down to the local nerd convention (Jaycar) and purchased a $1.50 glass reed switch and repaired the unit. Took about 1 Hour as is quite difficult to get back together. Also the alignment of the switch and the bending of its legs to fit was reasonably difficult. You could spend $10 or so on a surface mount jobby but this was more of a proof of fault repair for now.


I have only tested it for about an hour and a half but there have been no issues since.

The most important thing to note here is that even though Timbuch had a fault with his unit , the reed switchs may still click, as mentioned earlier in this thread, even if it does not 100% read the closure. You have to remember that the magnet is wizzing around pretty quick. The closure of the reed switch is affected by the strength of the magnetism and how long that magnetism is present near the reed switch. Obviously the greater the strength of the magnet and/or the longer the time spent near the switch, the better the chances of the reed switch closing and producing a meaningful reading. As when it does close the sensor in the power meter will need to see it close for a certain period of time before it can say "yes that is a closure the pedals have just turned". Otherwise the unit would pick up virabration from the road and give you a cadence reading which reads more like the tacho of an F1 car.

Anyway I now have to "reliability test" my new reapir work so bro it may be a little while till you get it back. LOL

 

[Tom Anhalt]

Very interesting Bloggy! I too have replaced reed switches on my 2 Polars...but those were the MUCH easier to replace speed sensors. Since I bought my 2 PMs used almost 3 years ago, the only issues I've had were with the speed sensors in which the wiring to the stock reed switch failed...from what I can tell, most likely due to moisture and corrosion. These failed very shortly after my acquisition of the used units. Like you, I got some replacement reed switches from the local "geek convention" and soldered the new ones in place. A nice big dollop of RTV and some contact cement to glue the speed sensor "case" back together and they've been going strong for almost 2.5 years.

Thanks for the explanation of your brother's problem...are you thinking of contacting Polar with what you found to see if they'll send him a new unit?

A little back ground first.

This is just in case anyone was watchin this thread to see how it goes. I have taken TimBuch's polar for testing. (I'm his Bro)

Basically after a short ride I noticed that his fault had appeared. I also noticed that the power readings dropped off at the same time that the cadence dropped out.
After a little fiddling with magnets I found that the cadence reed switch, even though it was clicking (ie apparently closing when the magnet was near), was not reading the magnet coming around correctly. Timbuch had sent it back to Polar previously and they had given the reply of no fault found.

Now I'm not suggesting that any one tries this next part with their's because it is a bugger of a job to get done and would probably void your warranty (that is if Polar will warrant it ).

I took the Power and cadence sensor unit apart and tested the reed switch with a multimeter. I found that there was about 2.8 Volts over the reed switch. Which is good by the way. I then tested with the magnet near and still found that the 2.8V was present. This is bad becasue it means that the reed switch is not closing. I then tested by shorting the reed switch with a piece of wire momentarily and hey presto the little green light flashed. ***Note that holding the wire on for a long period of time will not help because the sensor circuit is only looking for a momentary voltage spike. A longer closure would probably cause a fault in the sensor logic and it would discard the measurement as an anomoly.

So I went down to the local nerd convention (Jaycar) and purchased a $1.50 glass reed switch and repaired the unit. Took about 1 Hour as is quite difficult to get back together. Also the alignment of the switch and the bending of its legs to fit was reasonably difficult. You could spend $10 or so on a surface mount jobby but this was more of a proof of fault repair for now.


I have only tested it for about an hour and a half but there have been no issues since.

The most important thing to note here is that even though Timbuch had a fault with his unit , the reed switchs may still click, as mentioned earlier in this thread, even if it does not 100% read the closure. You have to remember that the magnet is wizzing around pretty quick. The closure of the reed switch is affected by the strength of the magnetism and how long that magnetism is present near the reed switch. Obviously the greater the strength of the magnet and/or the longer the time spent near the switch, the better the chances of the reed switch closing and producing a meaningful reading. As when it does close the sensor in the power meter will need to see it close for a certain period of time before it can say "yes that is a closure the pedals have just turned". Otherwise the unit would pick up virabration from the road and give you a cadence reading which reads more like the tacho of an F1 car.

Anyway I now have to "reliability test" my new reapir work so bro it may be a little while till you get it back. LOL

 

[Bloggy]

I asked timbuch if he wanted to contact them first as once it is opened it is good by warrantee. But he was quite angry about the whole "no fault found" issue and just decided that he didn't want too. I can't exactly try and claim a warrantee for him when I have no paper work. They would just laugh at me. I'm not even too sure that it would be covered now any way as I don't really know when he got it. I guess we should have a try though as they may now see some sense.

Good to see you got your speed sensors working. I have had issues in the past with my speed sensor, on my S150, but a better magnet sorted that out. I have to say that it seems they may have use the wrong components or had a bad batch or something cause a few people are turing to larger magnets to get these working when you expect that they would have done their homework when designing the sensors.

IMHO I think that the units are not designed well for vibration. There is no real stress relief on any of the components on the circuit boards. A little silicon would go a long way to sorting that out.

 

[Tom Anhalt]

I asked timbuch if he wanted to contact them first as once it is opened it is good by warrantee. But he was quite angry about the whole "no fault found" issue and just decided that he didn't want too. I can't exactly try and claim a warrantee for him when I have no paper work. They would just laugh at me. I'm not even too sure that it would be covered now any way as I don't really know when he got it. I guess we should have a try though as they may now see some sense.

Good to see you got your speed sensors working. I have had issues in the past with my speed sensor, on my S150, but a better magnet sorted that out. I have to say that it seems they may have use the wrong components or had a bad batch or something cause a few people are turing to larger magnets to get these working when you expect that they would have done their homework when designing the sensors.

IMHO I think that the units are not designed well for vibration. There is no real stress relief on any of the components on the circuit boards. A little silicon would go a long way to sorting that out.

One thing I forgot to mention is a little fact I learned about the cadence reed switch and the magnets. The reed switch is MUCH more sensitive to the magnet if the field lines are arranged parallel to the sensor module. In other words, don't point the North or South pole of the magnet at the sensor, align the North-South axis of the magnet parallel to the case. If you look at the Polar supplied crank magnet, you'll see that it corresponds to this.

I discovered this fact when using some scrap magnets from my work which are tall and thin and are magnetized parallel to the "tall" portion of the magnet.

I glued a couple of these magnets with the N-S axis of the pair parallel to the crank arm and the distance that they can trip the cadence sensor is quite impressive. If I were to turn them so that the N-S axis is perpendicular, they wouldn't trip the sensor unless the magnet was almost right on the case.

Just one more thing you might want to try (although it's probably too late...I guess that's for anyone else who may have similar issues).