Repair cyclometer? ...Nothing registers

Jeff Potter said:

I have an old Avocet cyclometer that has been beat up but has always
worked. When I started using it again this season there was no
display. I installed a fresh battery and now have a full display.
However, when I spin the wheel, nothing registers, no speed reading.

Should I make sure the magnet is totally clean? I'll do that right
now. I noticed there wer some small rust spots on it. The contacts all
seem fine.

I was wondering if maybe these magnets need remagnetizing ever. ??

I steelwooled the magnet. Nope. I cut the leads and reattached with fresh
wire to the sensor: nope. I cleaned sensor studs: nope. I cleaned display
contacts: nope.

It's an Avocet 40. It's been so great for so long. Anyone know how to
revive these things?

I'm doing an hour TT tomorrow at Waterford Raceway in Michigan with my
fully-faired highspeed HPV. A speedo is way helpful. But I'll live
without it. I'll be able to gauge myself by other riders, etc. But it is
a bit hard to be sure of speed inside such a rig. I hope to average 30mph
on this hilly, twisty, challenging course. Should be fun!

--

Jeff Potter
****
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[email hidden] (Jeff Potter) wrote :

Quoted message said:

However, when I spin the wheel, nothing registers, no speed reading.

One common cause for this is that the front wheel has been taken out,
and put back in so that the magnet on the spoke is now on the other
side, so that it can't come close enough to generate a signal.

HTH,
Erik

Jeff Potter said:

I have an old Avocet cyclometer that has been beat up but has always
worked. When I started using it again this season there was no
display. I installed a fresh battery and now have a full display.
However, when I spin the wheel, nothing registers, no speed reading.

Quoted message said:

Should I make sure the magnet is totally clean? I'll do that right
now. I noticed there were some small rust spots on it. The contacts
all seem fine.

The magnet doesn't care how dirty it is nor does the pickup. The
problem could be a bad connection at the pickup (those are plug-ins)
and corrosion of the contact pins on the instrument. It's best to put
some grease on the pins after cleaning them. That way they won't
corrode so fast again their plating probably being worn off.

Quoted message said:

I was wondering if maybe these magnets need remagnetizing ever. ??

No. Not unless you have placed them on a recording tape bulk eraser.
These magnets don't forget.

Jobst Brandt
[email hidden]

One thought - have you tried testing the computer by
connecting/disconnecting a piece of wire across the computer's connectors
instead of using the magnet - if you get the computer to register a reading
doing that then you know the problem isn't the computer itself.

Jerry

"Jeff Potter" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I have an old Avocet cyclometer that has been beat up but has always
worked. When I started using it again this season there was no
display. I installed a fresh battery and now have a full display.
However, when I spin the wheel, nothing registers, no speed reading.

Should I make sure the magnet is totally clean? I'll do that right
now. I noticed there wer some small rust spots on it. The contacts all
seem fine.

I was wondering if maybe these magnets need remagnetizing ever. ??

--JP

[email hidden] wrote in message news:<[email hidden]>...

Quoted message said:

Jeff Potter said:

I have an old Avocet cyclometer that has been beat up but has always
worked.

The
problem could be a bad connection at the pickup (those are plug-ins)
and corrosion of the contact pins on the instrument. It's best to put
some grease on the pins after cleaning them. That way they won't
corrode so fast again their plating probably being worn off.

Do you have a suggestion as to how best cleans those pins? I have
an old Avocet 50 that I treasure. I've replaced the mount several
times but the connection is flaky--I have to twist it until it
connects well then I don't dare touch it.

Keith

Jerry said:

One thought - have you tried testing the computer by
connecting/disconnecting a piece of wire across the computer's
connectors instead of using the magnet - if you get the computer to
register a reading doing that then you know the problem isn't the
computer itself.

Not a good test since the detector in the instrument looks for an AC
signal. You didn't say which model this is but if it runs from a
magnetic ring on the hub it will not respond to that test. Only units
with a single magnet on a spoke will register a contact closure.

Jobst Brandt
[email hidden]

Jerry said:

One thought - have you tried testing the computer by
connecting/disconnecting a piece of wire across the computer's
connectors instead of using the magnet - if you get the computer to
register a reading doing that then you know the problem isn't the
computer itself.

Not a good test since the detector in the instrument looks for an AC
signal. You didn't say which model this is but if it runs from a
magnetic ring on the hub it will not respond to that test. Only units
with a single magnet on a spoke will register a contact closure.

Jobst Brandt
[email hidden]

Keith Vetter said:

Quoted message said:

Quoted message said:

I have an old Avocet cyclometer that has been beat up but has
always worked.

Quoted message said:

Quoted message said:

The problem could be a bad connection at the pickup (those are
plug-ins) and corrosion of the contact pins on the instrument.
It's best to put some grease on the pins after cleaning them. That
way they won't corrode so fast again their plating probably being
worn off.

Quoted message said:

Do you have a suggestion as to how best cleans those pins? I have an
old Avocet 50 that I treasure. I've replaced the mount several times
but the connection is flaky--I have to twist it until it connects
well then I don't dare touch it.

As I said, grease the contacts after shining them up, preferably with
nothing more than a rag and Bon Ami cleanser. This is important
because Bon Ami, unlike most household cleansers, is not made of
"diamond" dust and doesn't scratch. It is essentially the product
Corning Ware furnishes for cleaning their products.

http://tinyurl.com/3aaf5

Also take a small probe and bend the contact tabs in the handlebar
mount to have a higher profile. That is usually not the problem but
rather one of contact pin corrosion.

Jobst Brandt
[email hidden]

Jeff Potter said:

I have an old Avocet cyclometer that has been beat up but has always
worked. When I started using it again this season there was no display.
I installed a fresh battery and now have a full display. However, when I
spin the wheel, nothing registers, no speed reading.
Should I make sure the magnet is totally clean? I'll do that right
now. I noticed there wer some small rust spots on it. The contacts all
seem fine.
I was wondering if maybe these magnets need remagnetizing ever. ??
--JP

If you have a friend in the electronics industry ask him/her about Caig
Laboratories DeoxIT. Ask them to show you how it works on your cycle
computer contacts... and you won't have the problem again:

<http://shopping.netledger.com/s.nl/c.ACCT113328/sc.2/category.188/it.A-
/id.1701/.f>

You may need a bit on each contact, and it will act as a protectant like
the grease Jobst is suggesting. It also helps on battery contacts. You
use very little, so don't buy it, just find a little from someone who
already has it and is willing to share a couple of drops.

--

Yes, sorry - I had missed the fact that some of the Avocet models use a
different sort of magnetic device. I have done this test on my computers but
these all use simple one magnet switches.

Jerry
<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Jerry said:

One thought - have you tried testing the computer by
connecting/disconnecting a piece of wire across the computer's
connectors instead of using the magnet - if you get the computer to
register a reading doing that then you know the problem isn't the
computer itself.

Not a good test since the detector in the instrument looks for an AC
signal. You didn't say which model this is but if it runs from a
magnetic ring on the hub it will not respond to that test. Only units
with a single magnet on a spoke will register a contact closure.

Jobst Brandt
[email hidden]

I put a wire across both computer contacts and it seemed like the
display did show a downward arrow (average getting slower) and maybe
registered 1mph instead of zero on the display. The display has always
worked---it just doesn't register any data. Also after my Sat. race I
notice that the speedo registered 15 max mph and 2.75 miles distance.
So it was working in some fashion for a moment anyway. Oh well. I'd
like to fix the thing but I don't know how. --JP

Keith Vetter said:

I have
an old Avocet 50 that I treasure. I've replaced the mount several
times but the connection is flaky--I have to twist it until it
connects well then I don't dare touch it.

I had a "flaky" connection at the handlebar mount on one of my bikes. I
now run the wire between the bar and the clamp to provide strain relief.
Problem solved. My ancient Avocet 40 is still going strong.

The OP should try cleaning the contacts on the computer and mount with
isopropl alcohol. Also, check the spacing and alignment between the magnet
and pickup. If all else fails, try a new mount kit.

Art Harris

Jeff Potter said:

I put a wire across both computer contacts and it seemed like the
display did show a downward arrow (average getting slower) and maybe
registered 1mph instead of zero on the display. The display has always
worked---it just doesn't register any data. Also after my Sat. race I
notice that the speedo registered 15 max mph and 2.75 miles distance.
So it was working in some fashion for a moment anyway. Oh well. I'd
like to fix the thing but I don't know how.

My gut feeling is that the computer is OK, and the problem is that
it's just not getting the signal from the sensor. Try to find someone
with the same computer, and temporarily swap them. See if the problem
follows the computer or the bike.

Art Harris

I missed the original post, but:

I had this problem - it was caused by the sheilding of the sensor cable
wearing through to the core and shorting on the frame. I put a bit of
electrical tape around it and it fixed the problem.

Regards

Bow

"Art Harris" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Jeff Potter said:

I put a wire across both computer contacts and it seemed like the
display did show a downward arrow (average getting slower) and maybe
registered 1mph instead of zero on the display. The display has always
worked---it just doesn't register any data. Also after my Sat. race I
notice that the speedo registered 15 max mph and 2.75 miles distance.
So it was working in some fashion for a moment anyway. Oh well. I'd
like to fix the thing but I don't know how.

My gut feeling is that the computer is OK, and the problem is that
it's just not getting the signal from the sensor. Try to find someone
with the same computer, and temporarily swap them. See if the problem
follows the computer or the bike.

Art Harris