Milometer Senser Problems

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Location
Loch side.
It is more likely than not the connector at the computer itself, between the bracket and unit. Lick it before fitting it, it may report back better.
 
Location
Loch side.
[QUOTE 4954623, member: 9609"]that connection died a few years back and I soldered the wires directly onto the computer - I suppose one of those wires could be loose. but no atter how much I tap / viabrate the computer I can't recreate the problem[/QUOTE]
It is very rare for the sensor to fail. It is a tiny little reed switch inside a glass capsule. Water can't get in and it is too small with such low inertia, that even a very hard shock won't break it. You can test it to an extent. The electrical circuit test should be obvious but you can also listen to it. Remove it from the fork, hold it next to (in) your ear and sweep a magnet past it. You'll hear it click click click.

I will climb into my loft this morning and see if I have any old harnesses with sensors up there for you. You can't buy the sensors separately but you can get a whole new harness for some of the quality brands like Cateye.
 
D

Deleted member 26715

Guest
Obvious things to check would be battery in sensor, distance of magnet to sensor, magnet having metal attached to it making it less efficient
 
D

Deleted member 26715

Guest
[QUOTE 4954829, member: 9609"]the curious thing is the problem is the other way to normal, it is registering too many clicks. I have certainly had problems in the past with poor connections that result in lower milage as clicks are missed.[/QUOTE]
I used to have a digital speedo on a kitcar which used the same principle magnet on wheel & sensor on suspension arm, quite often as you were driving along at 30 the speed would suddenly jump to 50+ making the distance between magnet & sensor very small seemed to correct it. I put it down to the reed switch, maybe when the magnet was too far away it chattered & created multiple pulses rather than a clean on/off.
 

Globalti

Legendary Member
The tiny reed switch is the same as used in magnetic door contacts for security alarms, they are very reliable and you can hear them going click click click if you spin the wheel. The most usual problem is water between the computer and the handlebar mount, contact pins that are worn out from years of vibration and mucky water or in your case, a dodgy solder.
 
Location
Loch side.
[QUOTE 4954829, member: 9609"]the curious thing is the problem is the other way to normal, it is registering too many clicks. I have certainly had problems in the past with poor connections that result in lower milage as clicks are missed.

I still tend to think this could be a problem in the wire, for instance if the insulation has broken down then vibration could cause shorting hence 'extra clicks and extra distance' . But the wire seems fine and it is only lightly tapping the reed switch sensor that seems to recreate the problem. (but I'm sort of thinking may be a reed switch could register with vibration, but then again forks on a bike wheel suffer lots of vibration so may be they don't ?)

Anyhows, I do remember buying a new cycle computer a few years back before I managed to fix the one I am using. If I can find it I can user the sensor off that to help identify the problem.[/QUOTE]
The reed switch does vibrate and make connections from noise other than the magnet. The switch even bounces and makes two or three connections per magnet revolution but the computer cancels that out by recognising it as noise. Yours maybe has dementia and forgets to cancel the noise.
 

Levo-Lon

Guru
Lady at work had some weird goings on with her bike puter..
I traced it to a crush in the link wire. Only about one strand left..
I re- joined it and it works fine.

Its such a fine wire.
 
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