Zebra Strip Contact Reliability

[Nelson]

I have head several devices over the years with LCDs that were
connected with Zebra strips and which subsequently
developed display problems due to the Zebra strip developing poor
contact with the PCB. Not surprising since the contact seems to rely
only on pressure. Cleaning the surfaces, eg with alcohol, and
reseating the strip helps for a while but the intermittent display
always seems to return.

Surely there must be some "connective glue" or other technique to
repair these things more permanently although I have been unable to
find anything with google.

Does anyone have any experience or recommendations regarding this?

 

[Samuel M. Goldwasser]

No solution other than to repeat cleaning that I know. Some
configurations are more susceptible. I just recently cleaned a Fluke
77 display that worked for 20 years that developed a segment that had
less contrast than the others.

Sometimes, figuring a way to very slightly increase the compressive
force will help in a marginal situation.

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[PanHandler]

Sometimes, figuring a way to very slightly increase the compressive
force will help in a marginal situation.

How 'bout an appropriately sized length of shrink wrap?

 

[PanHandler]

How 'bout an appropriately sized length of shrink wrap?

Meant heat shrink tubing.

 

[hr(bob) [email protected]]

I cleaned my Fluke for the second time, scrubbing the PCB contacts
thoroughly with alcohol. I was about to ask the group if anyone knew of a
safe way to clean the zebra contacts. (The very first cleaning needed in
nearly 20 years occurred four or five months ago.)

Any chance of coating the stripes with the conductive paint used for
automobile window heater strips. That would provide a new conductive
surface, and would be a bit thicker so that there would/should be more
pressure on the contact point.

Bob Hofmann

 

[Old Tech]

Nooo... you don't want anything that is electrically conductive
contacting either the Zebra strip or the display or the PCB. To do
so would short the individual conductive segments, which must remain
isolated from each other!!!! I've no experience with the
double-stick tapes mentioned above, but it's hard to envision that
as a solution to this problem. Might work, but I'd need it proven
to me before I could recommend it.
As was previously suggested, the only repair for this problem is
cleanliness and, if necessary, more pressure.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate
characters in the address)

Life is like a roll of toilet paper; the closer it gets to the end,
the faster it goes.

I have this problem on a car radio LCD display, when I get round to it
I am going to try something that we used to do on old TV turret
tuners - the contacts were silver plated and needed cleaning fairly
regularly. However, if after cleaning a VERY thin smear of vaseline
was applied to the contacts it was rare to have to clean them again.
You may think that the vaseline would insulate rather than improve
contact, but the light pressure of the leaf contact was enough to push
the vaseline aside. Vaseline is self healing so prevents oxidation. I
have used it successfully in remote control handset contacts, pots in
guitars and amps and even the home telephone. I would stress that the
smear of vaseline we are talking about here is just that - a very
light smear so as to almost be invisible. Wether or not it will work
on non-moving contacts remains to be seen.

Roy the Old Tech

 

[Jim Yanik]

I cleaned my Fluke for the second time, scrubbing the PCB contacts
thoroughly with alcohol. I was about to ask the group if anyone knew of a
safe way to clean the zebra contacts. (The very first cleaning needed in
nearly 20 years occurred four or five months ago.)

I wonder if Deoxit or cramolin would help?

 

[Jim Yanik]

afterthought , I suppose you meant conductive paint added to the pcb
pads (stripes), not the zebra (stripes)

why not use gold leaf on the PCB pads,build up thickness(increasing
contact pressure)?
conductive paint will be soft and contact pressure will force it aside and
possibly short out adjoining pads.

 

[Ancient_Hacker]

one guess is that the zebra strip is just fine but the pc contacts are
corroding. Shine the pads up with some #0000 steel wool, protect
them from corrosion with a dab of silicone grease, and reassemble.
Worth a shot.

 

[Old Tech]

Great idea. Then you can buy a new radio.

Why? If it doesnt work I will simply clean off the vaseline.

Roy the Old Tech