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]

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.

tinyurl.com3aaf5Open ↗

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]

Quoted post said:

Originally posted by Jeff Potter
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