Can you fix a zebra strip?

M

mike

Guest
I have a meter with intermittent display segments.
I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.
 
On Sat, 26 Jan 2013 21:12:10 -0800, mike <ham789@netzero.net> wrote:

I have a meter with intermittent display segments.
Click to expand...
Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.
Click to expand...
If you look carefully at the strip, you'll see that the connecting PCB
traces has created an indentation in the strip. If you rotate the
strip to a different side, the indentations will not make contact.
There are 8 possible ways to reinstall the strip, 7 of which won't
work. The trick will be to find the original orientation. Shaving
the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
<http://www.fujipoly.com/products/zebra-elastomeric-connectors.html>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
On 1/26/2013 11:13 PM, Jeff Liebermann wrote:
On Sat, 26 Jan 2013 21:12:10 -0800, mike<ham789@netzero.net> wrote:

I have a meter with intermittent display segments.

Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.

If you look carefully at the strip, you'll see that the connecting PCB
traces has created an indentation in the strip. If you rotate the
strip to a different side, the indentations will not make contact.
There are 8 possible ways to reinstall the strip, 7 of which won't
work. The trick will be to find the original orientation. Shaving
the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
http://www.fujipoly.com/products/zebra-elastomeric-connectors.html

Thanks for the link.
Click to expand...
It's a UEI EM150 vacuum gauge.
It's been sitting for a year. I figgered it would cold flow
and make connecti0n eventually. I was wrong. ;-(

I don't think the thing is worth the postage to order a new strip.

Think I'll try squeezing the strip sideways and heating it a little.
 
Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:u2k9g8hca88pq5d2c6lfj3lc4g4om8imn3@4ax.com...
On Sat, 26 Jan 2013 21:12:10 -0800, mike <ham789@netzero.net> wrote:

I have a meter with intermittent display segments.

Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.

If you look carefully at the strip, you'll see that the connecting PCB
traces has created an indentation in the strip. If you rotate the
strip to a different side, the indentations will not make contact.
There are 8 possible ways to reinstall the strip, 7 of which won't
work. The trick will be to find the original orientation. Shaving
the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
http://www.fujipoly.com/products/zebra-elastomeric-connectors.html

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Click to expand...

"There are 8 possible ways to reinstall the strip, 7 of which won't
work" ?
The point of zebras is they have very great latitude for mis-positioning,
I've found replacing back-in in another 1 of 8 orientations often works,
admittedly I flip in a vertical sense and flip longitudinally ,not
necessarily solved the problem for very long though.
Assuming the zebra is nominally held in a plastic well, then "shaving down
the plastic " does work , and is a more long term solution. I mark and use a
file to remove about 1/3mm all round, just freehand, again zebra latitude
comes to the fore again - I wonder who thought up such a clever solution.
 
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ke2r5g$4n0$1@dont-email.me...
Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:u2k9g8hca88pq5d2c6lfj3lc4g4om8imn3@4ax.com...
On Sat, 26 Jan 2013 21:12:10 -0800, mike <ham789@netzero.net> wrote:

I have a meter with intermittent display segments.

Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.

If you look carefully at the strip, you'll see that the connecting PCB
traces has created an indentation in the strip. If you rotate the
strip to a different side, the indentations will not make contact.
There are 8 possible ways to reinstall the strip, 7 of which won't
work. The trick will be to find the original orientation. Shaving
the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
http://www.fujipoly.com/products/zebra-elastomeric-connectors.html

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


"There are 8 possible ways to reinstall the strip, 7 of which won't
work" ?
The point of zebras is they have very great latitude for mis-positioning,
I've found replacing back-in in another 1 of 8 orientations often works,
admittedly I flip in a vertical sense and flip longitudinally ,not
necessarily solved the problem for very long though.
Assuming the zebra is nominally held in a plastic well, then "shaving
down
the plastic " does work , and is a more long term solution. I mark and use
a
file to remove about 1/3mm all round, just freehand, again zebra latitude
comes to the fore again - I wonder who thought up such a clever solution.
Click to expand...
I had a microwave display where the metal contact points under the zebra
strip were just soldered. Cleaning with solvent didn't help, a pencil eraser
was needed.

--
They can have my command prompt when they pry it from my cold dead fingers.
 
"N_Cook" <diverse@tcp.co.uk> wrote in news:ke2r5g$4n0$1@dont-email.me:

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:u2k9g8hca88pq5d2c6lfj3lc4g4om8imn3@4ax.com...
On Sat, 26 Jan 2013 21:12:10 -0800, mike <ham789@netzero.net> wrote:

I have a meter with intermittent display segments.

Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.

If you look carefully at the strip, you'll see that the connecting
PCB traces has created an indentation in the strip. If you rotate
the strip to a different side, the indentations will not make
contact. There are 8 possible ways to reinstall the strip, 7 of which
won't work. The trick will be to find the original orientation.
Shaving the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
http://www.fujipoly.com/products/zebra-elastomeric-connectors.html

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


"There are 8 possible ways to reinstall the strip, 7 of which won't
work" ?
The point of zebras is they have very great latitude for
mis-positioning, I've found replacing back-in in another 1 of 8
orientations often works, admittedly I flip in a vertical sense and
flip longitudinally ,not necessarily solved the problem for very long
though. Assuming the zebra is nominally held in a plastic well, then
"shaving down the plastic " does work , and is a more long term
solution. I mark and use a file to remove about 1/3mm all round, just
freehand, again zebra latitude comes to the fore again - I wonder who
thought up such a clever solution.
Click to expand...
Filing it is drastic and not reversable.

Instead, I recommend shimming between the bezel and the LCD glass (on top
of the glass) using a narrow strip of self-adhesive tape. You only
really need to shim the edge with the zebra strip. The glass then sits a
little closer to the PCB complessing the zebra strip slightly more.

It is the ONLY satisfactory method I have found if the clamping pressure
comes from plastic clips, not screws.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL
 
Ian Malcolm <See.My.Sig.for.email@totally.invalid> wrote in message
news:XnsA155693AA42B40xDEADBEEF@88.198.244.100...
"N_Cook" <diverse@tcp.co.uk> wrote in news:ke2r5g$4n0$1@dont-email.me:

Jeff Liebermann <jeffl@cruzio.com> wrote in message
news:u2k9g8hca88pq5d2c6lfj3lc4g4om8imn3@4ax.com...
On Sat, 26 Jan 2013 21:12:10 -0800, mike <ham789@netzero.net> wrote:

I have a meter with intermittent display segments.

Maker and model number?

I've cleaned the board and (carefully) the LCD glass contacts.
Not much help.
Neither did cleaning the zebra strip.
Is there anything I can do to the zebra strip to help?
I've thought about shaving down the plastic to get more compression
on the strip...but there's no coming back from that.

If you look carefully at the strip, you'll see that the connecting
PCB traces has created an indentation in the strip. If you rotate
the strip to a different side, the indentations will not make
contact. There are 8 possible ways to reinstall the strip, 7 of which
won't work. The trick will be to find the original orientation.
Shaving the existing connector won't help because it will reduce the
connection pressure.

However, I don't think you'll have much luck getting it back in
position. Find a replacement strip and it should work, assuming
nothing else is blown/broken/trashed. Search for "elastomeric
connector strip".
http://www.fujipoly.com/products/zebra-elastomeric-connectors.html

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


"There are 8 possible ways to reinstall the strip, 7 of which won't
work" ?
The point of zebras is they have very great latitude for
mis-positioning, I've found replacing back-in in another 1 of 8
orientations often works, admittedly I flip in a vertical sense and
flip longitudinally ,not necessarily solved the problem for very long
though. Assuming the zebra is nominally held in a plastic well, then
"shaving down the plastic " does work , and is a more long term
solution. I mark and use a file to remove about 1/3mm all round, just
freehand, again zebra latitude comes to the fore again - I wonder who
thought up such a clever solution.



Filing it is drastic and not reversable.

Instead, I recommend shimming between the bezel and the LCD glass (on top
of the glass) using a narrow strip of self-adhesive tape. You only
really need to shim the edge with the zebra strip. The glass then sits a
little closer to the PCB complessing the zebra strip slightly more.

It is the ONLY satisfactory method I have found if the clamping pressure
comes from plastic clips, not screws.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL
Click to expand...
yes the order is

clean all contact surfaces
tighten with spacers/shims where applicable
double flip the zebra
parts mule for a replacement
file job

My work-a-day DVM kept randomly loosing segments , went through 1 a few
times, 2 not applicable, 3 lasted a few months, 4 no mule found, finally 5
and has been reliable since then , perhaps 2 or 3 years now
 
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