Cylce computer not working

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike,
does nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc. So I checked the resistance of the magnetic pickup,
measures infinite (> 20 meg, anyway). Am I correct to assume the
pickup is simply a coil of wire, and this infinite reading indicates
an open circuit?

No. It is a reed switch. Infinite is normal. The switch closes when
near the magnet.

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike,
does nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc.

Hate to ask this, but did you try rotating the pickup a little closer to the
magnet?

(Also, if wireless, then check the p-u's battery.)

Obviously Yours, BS

Bill Sornson said:

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike,
does nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc.

Hate to ask this, but did you try rotating the pickup a little closer to the
magnet?

(Also, if wireless, then check the p-u's battery.)

Obviously Yours, BS

Bill-Thanks for the reply. It's a wired type (which I THOUGHT might be
more trouble free ;-( I did rotate the pickup as close as I dare, still
nogo. The instructions show it pretty much right on the rear facing
edge of the fork. Magnet itself seems strong. It occurs to my another
possibility is the pickup is a reed switch which closes when the magnet
passes, but again per my DMM this isn't happening. Best thing would be
to just RETURN the POS, but NATURALLY I can't find the bloddy receipt!!!

Dan

Dan said:

Bill Sornson said:

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike,
does nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to
wheel size etc.

Hate to ask this, but did you try rotating the pickup a little
closer to the magnet?

(Also, if wireless, then check the p-u's battery.)

Obviously Yours, BS

Bill-Thanks for the reply. It's a wired type (which I THOUGHT might
be more trouble free ;-( I did rotate the pickup as close as I dare,
still nogo. The instructions show it pretty much right on the rear
facing edge of the fork. Magnet itself seems strong. It occurs to
my another possibility is the pickup is a reed switch which closes
when the magnet passes, but again per my DMM this isn't happening.
Best thing would be to just RETURN the POS, but NATURALLY I can't
find the bloddy receipt!!!

Try moving it (the P-U) up a little, down a little, in a little more (even
if it hits the magnet), etc. If still no go, then it's either just plain
defective OR the wire got damaged during installation somehow.

(Someone correct me if I'm wrong, but doesn't a wired pickup make a little
click sound when the magnet passes?)

Good luck, Bill S.

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike, does
nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc. So I checked the resistance of the magnetic pickup, measures
infinite (> 20 meg, anyway). Am I correct to assume the pickup is
simply a coil of wire, and this infinite reading indicates an open circuit?

TIA

Dan

Dear Dan,

No, the pickup is a reed switch that closes when the magnet
goes past it, completing the circuit.

In a quiet room, you should be able to hear a very faint
click as you move the wheel back and forth to pass the
magnet next to the pickup.

Sometimes getting the broad face of the magnet to pass close
enough to the right part of the pickup can be tricky--the
pickup may need to be moved up or down on the fork leg, as
well as fiddled so that the magnet passes close to it.

You can take the magnet off the spoke, test that it is
indeed magnetic, and then wave it back and forth over the
pickup.

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

Good luck,

Carl Fogel

Jim Smith said:

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike,
does nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc. So I checked the resistance of the magnetic pickup,
measures infinite (> 20 meg, anyway). Am I correct to assume the
pickup is simply a coil of wire, and this infinite reading indicates
an open circuit?

No. It is a reed switch. Infinite is normal. The switch closes when
near the magnet.

Jim-Thanks, that was my 2nd guess. Contacts don't appear to close w/the
magnet, either.

Dan

Quoted message said:

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

I have never taken one of these apart, but every other reed switch I
have seen has been sealed in a glass tube. Are the contacts in a
cyclometer really bare?

"Bill Sornson" wrote: Try moving it (the P-U) up a little, down a little,
in a little more (even if it hits the magnet), etc(clip)
^^^^^^^^^^^^^^^^
I usually have better luck testing with a different magnet, like the one you
use for picking up screws, etc. Wave it over the pickup in various
directions and positions. Sometimes the location of the magnet wrt the reed
switch can be very touchy, and you may not get it right at first. Once you
see the switch closing and opening with a hand-held magnet, you can spend
all the time you need to get it working with the wheel magnet.

And, of course, if you see it not working, I would still go back to the LBS,
even without a receipt. They will recognize it if they sold it to you, and
I have found that most of the time they're pretty decent about exchanging
defective merchandise. Lot of times the guy behind the counter is also a
cyclist, who has gone through the same kind of thing you are going through.

It's too late for you, but I have installed three non wireless computers
in the last few months and make sure the computer is working before
cinching up the parts in their permanent location. You probably already
have checked the recommended distance between the pickup and the magnet,
but once I got that right, all of mine worked.

Jim Smith said:

Quoted message said:

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

I have never taken one of these apart, but every other reed switch I
have seen has been sealed in a glass tube. Are the contacts in a
cyclometer really bare?

Dear Jim,

I seem to recall disassembling (somewhat destructively) a
cyclocomputer pickup some years ago and being surprised to
find such a switch and sediment, but . . .

A) It would have been a dreadfully inexpensive model.

B) Your question makes me doubt my recollection. (I know
that I'm not supposed to do this, but I forget why.)

Thanks,

Carl Fogel

Quoted message said:

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike, does
nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc. So I checked the resistance of the magnetic pickup, measures
infinite (> 20 meg, anyway). Am I correct to assume the pickup is
simply a coil of wire, and this infinite reading indicates an open circuit?

TIA

Dan

Dear Dan,

No, the pickup is a reed switch that closes when the magnet
goes past it, completing the circuit.

In a quiet room, you should be able to hear a very faint
click as you move the wheel back and forth to pass the
magnet next to the pickup.

Sometimes getting the broad face of the magnet to pass close
enough to the right part of the pickup can be tricky--the
pickup may need to be moved up or down on the fork leg, as
well as fiddled so that the magnet passes close to it.

You can take the magnet off the spoke, test that it is
indeed magnetic, and then wave it back and forth over the
pickup.

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

Good luck,

Carl Fogel

Thanks for the replies. I found the pickup had to be no more than 1/4"
from the magnet to work, so I had to mount it to the inside of the fork
(not on the trailing edge, as depicted in the "manual"😉 which required
modifying the pickup a bit. Seems fine now.

Dan

Dan said:

Quoted message said:

Dan said:

Recently got a Schwinn SW500T cycle computer. Put it on the bike, does
nothing (no auto start, & when I do start it, doesn't record
distance/speed/time). Clock works, display works, can be set to wheel
size etc. So I checked the resistance of the magnetic pickup, measures
infinite (> 20 meg, anyway). Am I correct to assume the pickup is
simply a coil of wire, and this infinite reading indicates an open circuit?

TIA

Dan

Dear Dan,

No, the pickup is a reed switch that closes when the magnet
goes past it, completing the circuit.

In a quiet room, you should be able to hear a very faint
click as you move the wheel back and forth to pass the
magnet next to the pickup.

Sometimes getting the broad face of the magnet to pass close
enough to the right part of the pickup can be tricky--the
pickup may need to be moved up or down on the fork leg, as
well as fiddled so that the magnet passes close to it.

You can take the magnet off the spoke, test that it is
indeed magnetic, and then wave it back and forth over the
pickup.

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

Good luck,

Carl Fogel

Thanks for the replies. I found the pickup had to be no more than 1/4"
from the magnet to work, so I had to mount it to the inside of the fork
(not on the trailing edge, as depicted in the "manual"😉 which required
modifying the pickup a bit. Seems fine now.

Dan

Dear Dan,

Aha!

Yes, the magnet has to be very close to the pickup. A
quarter inch is actually an impressive clearance.

Sorry about that--I'm sure that I didn't mention how close
the magnet has to pass to the pickup. Like most others who
replied, I'm so used to the tiny clearance and fiddling
things up and down that I forgot how strange it seemed at
first.

Carl Fogel

Dan says...

Quoted message said:

Thanks for the replies. I found the pickup had to be no more than 1/4"
from the magnet to work, so I had to mount it to the inside of the fork
(not on the trailing edge, as depicted in the "manual"😉 which required
modifying the pickup a bit. Seems fine now.

Dan

I place the magnet and pickup as close as they can be without hitting
each other.

Quoted message said:

Quoted message said:

Thanks for the replies. I found the pickup had to be no more than 1/4"
from the magnet to work, so I had to mount it to the inside of the fork
(not on the trailing edge, as depicted in the "manual"😉 which required
modifying the pickup a bit. Seems fine now.

Dan

I place the magnet and pickup as close as they can be without hitting
each other.

I place the pickup on the _front_ of the fork so that, if it gets pushed in
a little, the magnet pushes it back out of the way instead of into the
spokes.

On Thu, 28 Apr 2005 02:56:20 GMT, "Alfred Ryder" <[email hidden]>
scribbled:

Quoted message said:

Quoted message said:

Quoted message said:

Thanks for the replies. I found the pickup had to be no more than 1/4"
from the magnet to work, so I had to mount it to the inside of the fork
(not on the trailing edge, as depicted in the "manual"😉 which required
modifying the pickup a bit. Seems fine now.

Dan

I place the magnet and pickup as close as they can be without hitting
each other.

I place the pickup on the _front_ of the fork so that, if it gets pushed in
a little, the magnet pushes it back out of the way instead of into the
spokes.

Ditto that.

-Slash
--
"Ebert Victorious"
-The Onion

Bill Sornson said:

Dan said:

Bill Sornson said:

Dan wrote:

> Recently got a Schwinn SW500T cycle computer. Put it on the bike,
> does nothing (no auto start, & when I do start it, doesn't record
> distance/speed/time). Clock works, display works, can be set to
> wheel size etc.

Hate to ask this, but did you try rotating the pickup a little
closer to the magnet?

(Also, if wireless, then check the p-u's battery.)

Obviously Yours, BS

Bill-Thanks for the reply. It's a wired type (which I THOUGHT might
be more trouble free ;-( I did rotate the pickup as close as I dare,
still nogo. The instructions show it pretty much right on the rear
facing edge of the fork. Magnet itself seems strong. It occurs to
my another possibility is the pickup is a reed switch which closes
when the magnet passes, but again per my DMM this isn't happening.
Best thing would be to just RETURN the POS, but NATURALLY I can't
find the bloddy receipt!!!

Try moving it (the P-U) up a little, down a little, in a little more (even
if it hits the magnet), etc. If still no go, then it's either just plain
defective OR the wire got damaged during installation somehow.

(Someone correct me if I'm wrong, but doesn't a wired pickup make a little
click sound when the magnet passes?)

Good luck, Bill S.

Yes. BUT ... the contacts inside a reed switch are very, very small. The sound
is very "little". Use a meter.

Dan said:

Bill-Thanks for the reply. It's a wired type (which I THOUGHT might be
more trouble free ;-( I did rotate the pickup as close as I dare, still
nogo. The instructions show it pretty much right on the rear facing
edge of the fork. Magnet itself seems strong. It occurs to my another
possibility is the pickup is a reed switch which closes when the magnet
passes, but again per my DMM this isn't happening. Best thing would be
to just RETURN the POS, but NATURALLY I can't find the bloddy receipt!!!

Dan

I had a friend who thought his battery was out, until I looked and
realized his head unit was not fully engaged in the mounting braket.
Maybe?

--
Craig Brossman, Durango Colorado
remove "mydebt" to reply

"Anyone who isn't confused really doesn't understand the situation."
Edward R. Murrow

Jim Smith said:

Quoted message said:

If you hear no click and no speed reading appears, then
you've probably got a bad reed switch. Water, for example,
can get in from road splashing or deep water, evaporate, and
leave sediment on the delicate switch.

I have never taken one of these apart, but every other reed switch I
have seen has been sealed in a glass tube. Are the contacts in a
cyclometer really bare?

The typical reed relay body is indeed a glass tube and the contacts themselves
are therefore sealed and protected from the environment. But the contacts must
connect to something on the outside of the sealed chamber so that wire
connections can be made. *There* is where a potential problem arises; if thoe
contact-lead/wire interfaces are open to the air then they are susceptable to
the effects of corrosion.

Alfred Ryder said:

I place the pickup on the _front_ of the fork so that, if it gets pushed in
a little, the magnet pushes it back out of the way instead of into the
spokes.

Good idea. The pickups of my Schwinn cyclos have a large, flat mounting face.
The forks of both my bike are wider than they are thick, and so these pickups
cannot rotate. Properly strapped down, one would probably either slap the
magnet aside or, if magnet is tight to spoke, twist the spoke all to h__l.