Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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  #1   Report Post  
Sean
 
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Default stripping "ribbon cable?" ??

Hi,
I had to open my projector to fix a problem with it and I notice a break in
one of the "ribbon cables" coming from one of the LCD panels..

This cable is completely flat and has "gold fingers" at the end of it (not
the traditional wire that i'm used to dealing with) .. I can see through the
insulation a break in a couple of the tracks so I need to trim the cable
back..

Question is, how do you remove the insulation on the end of one of these
cables!?!? .. I really need to get this right the first time coz there's not
much further back that I can trim it..

Any info would be greatly appreciated (note if replying by email remove the
NOSPAM)

Thanks,

Sean


  #2   Report Post  
NSM
 
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Default


"Sean" wrote in message
...

Hi,
I had to open my projector to fix a problem with it and I notice a break

in
one of the "ribbon cables" coming from one of the LCD panels..

This cable is completely flat and has "gold fingers" at the end of it (not
the traditional wire that i'm used to dealing with) .. I can see through

the
insulation a break in a couple of the tracks so I need to trim the cable
back..

Question is, how do you remove the insulation on the end of one of these
cables!?!? .. I really need to get this right the first time coz there's

not
much further back that I can trim it..


I'd be inclined to try to patch the cable. Sometimes the ends are special,
not just stripped cable.
--
N

















  #3   Report Post  
Jumpster Jiver
 
Posts: n/a
Default

"ribbon cables"...
Question is, how do you remove the insulation on the end of one of these
cables!?!? .. I really need to get this right the first time coz there's not
much further back that I can trim it..



Usually these cables are replaced, not repaired.
If you can get a new part from the manufacturer you'd be much better off
than trying to repair it. It's nearly impossible and not worth the effort.

  #4   Report Post  
CJT
 
Posts: n/a
Default

Sean wrote:
Hi,
I had to open my projector to fix a problem with it and I notice a break in
one of the "ribbon cables" coming from one of the LCD panels..

This cable is completely flat and has "gold fingers" at the end of it (not
the traditional wire that i'm used to dealing with) .. I can see through the
insulation a break in a couple of the tracks so I need to trim the cable
back..

Question is, how do you remove the insulation on the end of one of these
cables!?!? .. I really need to get this right the first time coz there's not
much further back that I can trim it..

Any info would be greatly appreciated (note if replying by email remove the
NOSPAM)

Thanks,

Sean


Usually ribbon cable is used with insulation displacement connectors,
so isn't stripped.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .
  #5   Report Post  
Rick
 
Posts: n/a
Default

"Sean" wrote in message ...
Hi,
I had to open my projector to fix a problem with it and I notice a break in
one of the "ribbon cables" coming from one of the LCD panels..

This cable is completely flat and has "gold fingers" at the end of it (not
the traditional wire that i'm used to dealing with) .. I can see through the
insulation a break in a couple of the tracks so I need to trim the cable
back..


Are you sure these breaks are causing a problem? If it ain't
broke, etc.

You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.




  #6   Report Post  
Sean
 
Posts: n/a
Default


You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.


I thought the same thing, but I can't see how conductive paint can be used
when the whole thing is insulated.. it's basically flexible PCB.. I have
ended up cutting it back but that doesn't help because now I've lost the
gold connectors..
I'm guessing there's no way to fix the cable now!?

If not, can this sort of cable be bought.. is it standard!?

Thanks,

Sean


  #7   Report Post  
Jumpster Jiver
 
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Default

can this sort of cable be bought.. is it standard!?


If you can get in touch with the manufacturer's parts department maybe
you could order it. It's probably not available anywhere else.


  #8   Report Post  
Ian Malcolm
 
Posts: n/a
Default

Sean wrote:
You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.



I thought the same thing, but I can't see how conductive paint can be used
when the whole thing is insulated.. it's basically flexible PCB.. I have
ended up cutting it back but that doesn't help because now I've lost the
gold connectors..
I'm guessing there's no way to fix the cable now!?

If not, can this sort of cable be bought.. is it standard!?

Thanks,

Sean


If its water clear plastic the method below WILL NOT WORK
(plated/conductive ink tracks and low melting point plastic), but at
this point you have nothing to loose so try it anyway. It also works
for the white ribbbon cables with the pretinned conductors but skip the
tinning step below (a *brief* touch with an iron can help you scrape off
the last of the white plastic but always risks lifting a track)

If its all a sort of golden yellow colour, the cable is almost certainly
a Kapton substate flexible PCB with an additional layer laminated on top.

AS LONG AS THE TRACK SPACING AND ORDER IS IDENTICAL AT THE BREAK AND THE
END ITS FIXABLE.

Take an *ADJUSTABLE* Dremel tool (actually the really cheap clone ones
with the external powerbrick works fine for this sort of stuff, fit a
small ball ended DIAMOND burr and turn the speed down pretty slow. Take
a fine tipped pen (e.g. CD marker) and mark off the length you need to
strip. Grind off the top layer from each contact one at a time. Keep
the burr moving around all the time or you will go right through. When
you see a spot of bare copper, work around it, dont go back over it
because its VERY thin. Its best to work against a slightly resiliant
backing such as a block of expanded polystyrene or a pencil erasor.

Finally finish by fluxing the contacts with a flux pen or some liquid
rosin flux and tinning all the contacts (very little solder, fine tipped
iron and *very* brief contact. Any small remaining sport of Kapton can
be cleaned off the tinned surface using a small jewlers screwdriver with
the end ground at an angle as a knife blade, edge at 45 deg. to shaft
and about a 30 deg included angle at the actual cutting edge. Sharpen
on a fine india stone or 600 grit wet & dry paper using some light oil.
(usefull general purpose tool when patching fine pcbs) Scrape very
gently. Clean up excess tinning with fine desoldering braid ( braid
touching the tip, then briefly wipe the contact with the braid still
touching the tip) Trim back to fresh braid for every contact. If
you've done it right none of the tracks have lifted. I've had some
success sticking one or two back down with a tiny drop of superglue
applied with a toothpick and hold the track down gently for five minutes
with a very small screwdriver or the point of the scraper mentioned above.

Finally, if there is a backing strip on the original connector, strip it
off carefully using a thin sharp knife to worry at the glue line (or
even the above scraper again). Remove any residual glue with some
solvent and a cotton bud. Roughen the surface with the diamond bur on
really slow and do the same to the back side of the ribbon cable Stick
in place with a tiny drop of suitable glue (I dont like superglue for
this, it doesnt stand up to being flexed and it tends to get on the
track side and rip tracks off when you take the clamp off) Clamp flat
till fully dry. Clean the tinned contacts with isopropyl alcohol or
methylated spirits and a cotton bud. Apply the lightest smear of a good
contact cleaner/lubricant (to slow down the inevitable tarnishing) and
insert into matching socket and pray to Deity of Your Preference :-)


I STRONGLY reccomend practicing on the scrap end you cut off. DONT
strip the wrong side of the cable (LOOK AT THE SOCKET CONTACTS!). I did
a £1000 proffesional video head last week and it took me about an hour
for about 20 contacts. (now that was really fiddly, grinding cables 1"
away from a really delicate head drum and having to keep both head
cables (both damaged) the same length to maintain rotational balance) :-)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you must.
  #9   Report Post  
Ian Malcolm
 
Posts: n/a
Default

Jumpster Jiver wrote:

can this sort of cable be bought.. is it standard!?



If you can get in touch with the manufacturer's parts department maybe
you could order it. It's probably not available anywhere else.



If its a streight cable with both ends the same and detachable, take it
down a good video repair shop and see if they can match it. So long as
the contact pitch is correct you can always cut down a wider cable.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you must.
  #10   Report Post  
geo73
 
Posts: n/a
Default

I think this kind of ribbon goes with the lcd...
If you manage to order the kit will you be able to
adjust the lcd to the rest of the prism??





  #11   Report Post  
Sean
 
Posts: n/a
Default

Thanks so much for the info.. I'll have to look into whether I'm up for it..
I really wish near where I lived there was someone I could pay to do this..
I mean since the projector is worth over $2500 it'd be worth paying upto
about $1000 to get someone to do this.. pretty good for an hours work!

I just need some of the equipment

--
Sean

"Ian Malcolm" wrote in message
...
Sean wrote:
You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.



I thought the same thing, but I can't see how conductive paint can be
used when the whole thing is insulated.. it's basically flexible PCB.. I
have ended up cutting it back but that doesn't help because now I've lost
the gold connectors..
I'm guessing there's no way to fix the cable now!?

If not, can this sort of cable be bought.. is it standard!?

Thanks,

Sean

If its water clear plastic the method below WILL NOT WORK
(plated/conductive ink tracks and low melting point plastic), but at this
point you have nothing to loose so try it anyway. It also works for the
white ribbbon cables with the pretinned conductors but skip the tinning
step below (a *brief* touch with an iron can help you scrape off the last
of the white plastic but always risks lifting a track)

If its all a sort of golden yellow colour, the cable is almost certainly a
Kapton substate flexible PCB with an additional layer laminated on top.

AS LONG AS THE TRACK SPACING AND ORDER IS IDENTICAL AT THE BREAK AND THE
END ITS FIXABLE.

Take an *ADJUSTABLE* Dremel tool (actually the really cheap clone ones
with the external powerbrick works fine for this sort of stuff, fit a
small ball ended DIAMOND burr and turn the speed down pretty slow. Take a
fine tipped pen (e.g. CD marker) and mark off the length you need to
strip. Grind off the top layer from each contact one at a time. Keep the
burr moving around all the time or you will go right through. When you
see a spot of bare copper, work around it, dont go back over it because
its VERY thin. Its best to work against a slightly resiliant backing such
as a block of expanded polystyrene or a pencil erasor.

Finally finish by fluxing the contacts with a flux pen or some liquid
rosin flux and tinning all the contacts (very little solder, fine tipped
iron and *very* brief contact. Any small remaining sport of Kapton can be
cleaned off the tinned surface using a small jewlers screwdriver with the
end ground at an angle as a knife blade, edge at 45 deg. to shaft and
about a 30 deg included angle at the actual cutting edge. Sharpen on a
fine india stone or 600 grit wet & dry paper using some light oil.
(usefull general purpose tool when patching fine pcbs) Scrape very gently.
Clean up excess tinning with fine desoldering braid ( braid touching the
tip, then briefly wipe the contact with the braid still touching the tip)
Trim back to fresh braid for every contact. If you've done it right none
of the tracks have lifted. I've had some success sticking one or two back
down with a tiny drop of superglue applied with a toothpick and hold the
track down gently for five minutes with a very small screwdriver or the
point of the scraper mentioned above.

Finally, if there is a backing strip on the original connector, strip it
off carefully using a thin sharp knife to worry at the glue line (or even
the above scraper again). Remove any residual glue with some solvent and a
cotton bud. Roughen the surface with the diamond bur on really slow and
do the same to the back side of the ribbon cable Stick in place with a
tiny drop of suitable glue (I dont like superglue for this, it doesnt
stand up to being flexed and it tends to get on the track side and rip
tracks off when you take the clamp off) Clamp flat till fully dry. Clean
the tinned contacts with isopropyl alcohol or methylated spirits and a
cotton bud. Apply the lightest smear of a good contact cleaner/lubricant
(to slow down the inevitable tarnishing) and insert into matching socket
and pray to Deity of Your Preference :-)


I STRONGLY reccomend practicing on the scrap end you cut off. DONT strip
the wrong side of the cable (LOOK AT THE SOCKET CONTACTS!). I did a £1000
proffesional video head last week and it took me about an hour for about
20 contacts. (now that was really fiddly, grinding cables 1" away from a
really delicate head drum and having to keep both head cables (both
damaged) the same length to maintain rotational balance) :-)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you must.



  #12   Report Post  
nolsar
 
Posts: n/a
Default

Take it to a repair joint anywhere, probly $50 an hour.

"Sean" wrote in message
...
Thanks so much for the info.. I'll have to look into whether I'm up for

it..
I really wish near where I lived there was someone I could pay to do

this..
I mean since the projector is worth over $2500 it'd be worth paying upto
about $1000 to get someone to do this.. pretty good for an hours work!

I just need some of the equipment

--
Sean

"Ian Malcolm" wrote in message
...
Sean wrote:
You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.



I thought the same thing, but I can't see how conductive paint can be
used when the whole thing is insulated.. it's basically flexible PCB..

I
have ended up cutting it back but that doesn't help because now I've

lost
the gold connectors..
I'm guessing there's no way to fix the cable now!?

If not, can this sort of cable be bought.. is it standard!?

Thanks,

Sean

If its water clear plastic the method below WILL NOT WORK
(plated/conductive ink tracks and low melting point plastic), but at

this
point you have nothing to loose so try it anyway. It also works for the
white ribbbon cables with the pretinned conductors but skip the tinning
step below (a *brief* touch with an iron can help you scrape off the

last
of the white plastic but always risks lifting a track)

If its all a sort of golden yellow colour, the cable is almost certainly

a
Kapton substate flexible PCB with an additional layer laminated on top.

AS LONG AS THE TRACK SPACING AND ORDER IS IDENTICAL AT THE BREAK AND THE
END ITS FIXABLE.

Take an *ADJUSTABLE* Dremel tool (actually the really cheap clone ones
with the external powerbrick works fine for this sort of stuff, fit a
small ball ended DIAMOND burr and turn the speed down pretty slow. Take

a
fine tipped pen (e.g. CD marker) and mark off the length you need to
strip. Grind off the top layer from each contact one at a time. Keep

the
burr moving around all the time or you will go right through. When you
see a spot of bare copper, work around it, dont go back over it because
its VERY thin. Its best to work against a slightly resiliant backing

such
as a block of expanded polystyrene or a pencil erasor.

Finally finish by fluxing the contacts with a flux pen or some liquid
rosin flux and tinning all the contacts (very little solder, fine tipped
iron and *very* brief contact. Any small remaining sport of Kapton can

be
cleaned off the tinned surface using a small jewlers screwdriver with

the
end ground at an angle as a knife blade, edge at 45 deg. to shaft and
about a 30 deg included angle at the actual cutting edge. Sharpen on a
fine india stone or 600 grit wet & dry paper using some light oil.
(usefull general purpose tool when patching fine pcbs) Scrape very

gently.
Clean up excess tinning with fine desoldering braid ( braid touching the
tip, then briefly wipe the contact with the braid still touching the

tip)
Trim back to fresh braid for every contact. If you've done it right

none
of the tracks have lifted. I've had some success sticking one or two

back
down with a tiny drop of superglue applied with a toothpick and hold the
track down gently for five minutes with a very small screwdriver or the
point of the scraper mentioned above.

Finally, if there is a backing strip on the original connector, strip it
off carefully using a thin sharp knife to worry at the glue line (or

even
the above scraper again). Remove any residual glue with some solvent and

a
cotton bud. Roughen the surface with the diamond bur on really slow and
do the same to the back side of the ribbon cable Stick in place with a
tiny drop of suitable glue (I dont like superglue for this, it doesnt
stand up to being flexed and it tends to get on the track side and rip
tracks off when you take the clamp off) Clamp flat till fully dry.

Clean
the tinned contacts with isopropyl alcohol or methylated spirits and a
cotton bud. Apply the lightest smear of a good contact

cleaner/lubricant
(to slow down the inevitable tarnishing) and insert into matching socket
and pray to Deity of Your Preference :-)


I STRONGLY reccomend practicing on the scrap end you cut off. DONT

strip
the wrong side of the cable (LOOK AT THE SOCKET CONTACTS!). I did a

£1000
proffesional video head last week and it took me about an hour for about
20 contacts. (now that was really fiddly, grinding cables 1" away from a
really delicate head drum and having to keep both head cables (both
damaged) the same length to maintain rotational balance) :-)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you

must.




  #13   Report Post  
Asimov
 
Posts: n/a
Default

"Sean" bravely wrote to "All" (16 May 05 12:24:01)
--- on the heady topic of " stripping "ribbon cable?" ??"

Se From: "Sean"
Se sci.electronics.repair:48309

You'd almost certainly be better off patching the tracks with
some conductive paint, rather than try and reattach the entire
cable.


Se I thought the same thing, but I can't see how conductive paint can be
Se used when the whole thing is insulated.. it's basically flexible PCB..
Se I have ended up cutting it back but that doesn't help because now I've
Se lost the gold connectors..
Se I'm guessing there's no way to fix the cable now!?

Se If not, can this sort of cable be bought.. is it standard!?

Remove the sockets and solder in some ordinary wire ribbon cable or
jumper wires if you have the patience. Had to do that with early rca
vcr's that had crummy spring type sockets.

A*s*i*m*o*v

.... Digital circuits are made from analog parts.

  #14   Report Post  
Jim Adney
 
Posts: n/a
Default

On Mon, 16 May 2005 10:58:35 +0800 "Sean"
wrote:

I had to open my projector to fix a problem with it and I notice a break in
one of the "ribbon cables" coming from one of the LCD panels..


Would it be possible to just run a single conductor wire in parallel
with the single broken conductor, and leave the rest of the ribbon
undisturbed? The single wire might not need to be soldered right at
the end of the ribbon either. If it is carrying low frequency info it
could be connected to any nearby point that is connected to the
conductor you're trying to fix.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------
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