stripping "ribbon cable?" ??

in

the

not

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

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.

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

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.

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

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 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) :-)

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.

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??

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

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

it..

this..

lost

this

last

the

such

be

the

gently.

tip)

none

back

even

Clean

cleaner/lubricant

strip

must.

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

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

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.

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 snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

-----------------------------------------------