Repair a BC 800 cyclocomputer

Quoted message said:

Hi:

I have an older model Sigma BC 800 cyclocomputer. The button that
switches between modes (trip time, avg speed, total distance, etc.)
sticks and makes it difficult to switch between modes. Anyone know if
the unit can be taken apart (such that it could be put back together,
of course)?

Sounds like a typical electronic repair, probably dirty contacts. I've never
opened a Sigma so don't know just what they use for a switch.

Any decent bench tech can probably fix it. Any decent bench tech will probably
charge more for his time than it's worth.

Ron

Hi Ron:

I'm pretty sure that I can fix the electronics once inside. But the
problem is I don't know that it can be taken apart. I see no screws.
It's got two halves (front and back) but they look sealed together.
Don't know if they come apart. Someone offered me their old one. Once
I get that one, then I'll try prying apart my problematic one. I don't
know if it's glued together or if it's got clips that will break off or
what.

Thanks.
Kevin

RonSonic said:

Quoted message said:

Hi:

I have an older model Sigma BC 800 cyclocomputer. The button that
switches between modes (trip time, avg speed, total distance, etc.)
sticks and makes it difficult to switch between modes. Anyone know if
the unit can be taken apart (such that it could be put back together,
of course)?

Sounds like a typical electronic repair, probably dirty contacts. I've never
opened a Sigma so don't know just what they use for a switch.

Any decent bench tech can probably fix it. Any decent bench tech will probably
charge more for his time than it's worth.

Ron

Quoted message said:

Hi Ron:

I'm pretty sure that I can fix the electronics once inside. But the
problem is I don't know that it can be taken apart. I see no screws.
It's got two halves (front and back) but they look sealed together.
Don't know if they come apart. Someone offered me their old one. Once
I get that one, then I'll try prying apart my problematic one. I don't
know if it's glued together or if it's got clips that will break off or
what.

Where's the battery go? Screws in the compartment? [censored], snap together
construction? Screws hidden under a glue-on escutcheon or badge?

You know the saying: Be brave, it's already broke.

Ron

Quoted message said:

Thanks.
Kevin

RonSonic said:

Quoted message said:

Hi:

I have an older model Sigma BC 800 cyclocomputer. The button that
switches between modes (trip time, avg speed, total distance, etc.)
sticks and makes it difficult to switch between modes. Anyone know if
the unit can be taken apart (such that it could be put back together,
of course)?

Sounds like a typical electronic repair, probably dirty contacts. I've never
opened a Sigma so don't know just what they use for a switch.

Any decent bench tech can probably fix it. Any decent bench tech will probably
charge more for his time than it's worth.

Ron

[email hidden said:

"]Hi:

I have an older model Sigma BC 800 cyclocomputer. The button that
switches between modes (trip time, avg speed, total distance, etc.)
sticks and makes it difficult to switch between modes. Anyone know if
the unit can be taken apart (such that it could be put back together,
of course)?

Thanks.
Kevin

If you've got the older model that looks like this:
bike-on.comsmSigmaSportComputer.jpgOpen ↗

you've possibly got the same problem I had.

That blue button at the bottom clips in at either edge. You can pop
it out by wedging something thin under the middle of it.

There's a microswitch that the blue button activates. Taking the blue
button off and manually pressing the microswitch fixed things for me.

I never managed to get the blue button working again - it wanted to
stay kind of half-pressed.

Steve

ps. *do not* replace this with the new model BC800. It is not the same.
No average speed. Only one wheel size. No above/below avg indicator.

It's difficult to switch to the different display modes; but it still
works fine otherwise. During a ride, I'd prefer to be able to look at
my trip stats thus far. But I can still at least see my current speed
(which shows full time anyway) and then get my current speed average by
looking at the up or down arrows (which also show full time) and
comparing the arrows to my current speed. After the ride is when I
spend several minutes trying to get it to show me my total trip
distance, time, etc. I'll bust it open after the replacement arrives.

Thanks.

Kevin

The one in your link is a little different than mine but still has the
same button layout, including the blue button on the bottom.

Here's mine:
http://ksmdomain.net/biking/my_bc800.jpg

After the button is off, can you get to the switch while you're riding?

Thanks for the tip about the new model. I saw it but wasn't sure if it
would fit/work in my wireless mount. I had no idea that they actually
removed features. That stinks!

I have two of these older head units and a wireless transmitter system
on each of my three bikes. I use one head unit on my "good" road bike
and share the other between my mountain bike and "old" road bike (which
requires the dual wheel size feature). The unit on my mountain bike
has taken a ton of abuse, including being under water for several
minutes, and it still works flawlessly. I love the display. I can see
it clearly even when going over a ton of rocks and other bumps downhill
on the moutain bike. I don't know what's up with the blue button on my
other one. That unit has only been on my road bike, which sees
relatively smooth roads.

Thanks again.
Kevin

I just re-read my post and by showing "full time" I meant it shows it
"continuously."

Kevin

[email hidden said:

"]The one in your link is a little different than mine but still has the
same button layout, including the blue button on the bottom.

Here's mine:
http://ksmdomain.net/biking/my_bc800.jpg

After the button is off, can you get to the switch while you're riding?
[...]

I thought the picture I posted originally looked a little strange - the one
you've linked is the model I had.

From what I remember you can't really operate the switch with your
fingers - you'd need something thin like the end of a pen.

Steve

I'm afraid the answer to the question is NO, this BC 800 counter cannot be taken apart without breaking the shell. The halves are glued together and it can only be prised open with force. If you'd care to have a look at the inside, here you are:

[IMG]cyclingforums.com700Open ↗[/IMG]