Page 1 of Any electronics engineers out there?

Just bought a second DECT phone to replace my old handset as my display and charging abilities had gone on mine.
Had it for about ten years and I`ve never yet found a DECT phone to match it!
Anyway, new one turned up and works great, on the old one found out was just a bad contact on the charger so that`s sorted but the display (LCD and I thought it had gone completely) turns out it had just become unsecured from it`s contacts.
Looks like it`s a sort of adhesive ribbon cable that stuck to a set of connectors, possibly around 15 to 20 (didn`t look close enough)

I`ve cleaned it all up using flux cleaner and the contacs on both sides are perfect. Pressing it into place by hand works when the connections are made and the display functions perfectly.
Now comes the hard bit.

Does anyone have any idea of something that will re-stick it into place?
Would have to allow the contacts to make their connections obviously and I can solder new ones to the circuit board side but the ribbon cable is plastic so if I try to solder to that it`ll just melt into nothing (tried that before on a keyboard membrane)
Can`t get a replacement because it`s over ten years old (and probably negate the option due to cost) so any sensible ideas welcomed.
It`s in a tricky bit to do and needs to be in perfect place or casing won`t close so cant extend it etc.

Jimbo : oÞ

"Making Teenagers depressed is like shooting fish inna barrel"

This item was edited on Tuesday, 15th June 2010, 19:14

Tricky. Remaking joints on plastic ribbon cables is nigh on impossible. I have done it in the past, but that was by bridging each connection with standard wire, but in your case, this would be no good, as it would stop the case from fastening.

The only thing I can think of suggesting, is to add a small layer of solder to the circuit board connections, and then simply glue the plastic portions of the ribbon to the board, hopefully leaving the solder connections clear and connecting. This would not be perfect, and may give intermittent connection on some of the pads.

Sorry, s`all I can think of, without actually seeing the unit.

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I have done it in the past, but that was by bridging each connection with standard wire, but in your case, this would be no good, as it would stop the case from fastening.I I can get a small length in there it should be ok, just not got much to play with. Other problem will be the quantity of connections but my idea in my head was to have a piece of wire connection to each ribbon connection, remove small amount of ribbon to expose the said wire and solder to mainboard, but this will be exceptionally tricky even just from the small lengths and disconnecting the new connection.
Also, concerned about the ribbon melting so any ideas there would be brilliant.

Got plenty of 30AWG Kynar so that`s not an issue and I`ve done a small amount of SMD soldering work... not a huge amount and only single components or removals.

Jimbo : oÞ

"Making Teenagers depressed is like shooting fish inna barrel"

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Also, concerned about the ribbon melting so any ideas there would be brilliant.

Do you have, or can you borrow a fibreglass pen? Use it to scratch through the plastic film, exposing a small section of the copper track, and just solder directly to it. Remember to use small touches of the solder and iron, so as not to transfer too much heat to the surrounding area.
If you do melt more of the plastic, just apply a non-conductive paint to stop any shorts. I find that clear nail polish is very good for this.

With regard to the number of connections to be made; just take your time, patience is the key, and double check your connections before soldering.

This item was edited on Tuesday, 15th June 2010, 23:03

Dunno if this will help. When I replaced the screen in my boy`s PSP, one of the little plastic clippy slots for a plastic ribbon cable broke. I stretched a thin bit of Blu-Tac (other reusable adhesive putty products are available) over it to hold it down and it has worked ever since.

---

Could someone please
Remove these cutleries
From my knees...

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Do you have, or can you borrow a fibreglass pen?Got one, ribbon is very flimsy though but this is probably the best idea so far... especially if I can tin the contacts on the motherboard then just tough for a second to create the joint to the ribbon.

Siz of the connections aren`t too worrying, try to reconnect missing pins on an SMD chip to get the idea of how small I`ve done ;) (with lots of screw ups I may add! Lol)

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Dunno if this will help. When I replaced the screen in my boy`s PSP, one of the little plastic clippy slots for a plastic ribbon cable broke. I stretched a thin bit of Blu-Tac (other reusable adhesive putty products are available) over it to hold it down and it has worked ever since.Opposite problem Mister Smee. Imagine if you had bent the ribbon and broken it slightly so need to reconnect it... that would be more similar.
However, using blu-tac you`ve been lucky it held. The solution for your problem though (especially if you still have the wee bit of plastic) is to use a touch of hot melt glue ;)

Jimbo : oÞ

"Making Teenagers depressed is like shooting fish inna barrel"

This all sounds very much like the classic problems with a ZX81 keyboard connector, which might mean searching for solutions to that may help.

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with a ZX81Got one of them too ;) :D
Cheers for the heads up, I`ll try searching that too before I start again this afternoon :)
Doesn`t really matter if I screw it up, it works without a display just it would be nicer if it had one is all.

Jimbo : oÞ

"Making Teenagers depressed is like shooting fish inna barrel"

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Siz of the connections aren`t too worrying, try to reconnect missing pins on an SMD chip to get the idea of how small I`ve done

With you there, brother. ;)

I used to swap the bloody things by hand, as the boss was too tight to buy the correct gear. Mind you, in them days, them wasn`t cheap! :o


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This all sounds very much like the classic problems with a ZX81 keyboard connector

Ah, yes, I remember it well! That, and the `wobbly` 16k ram pack! >:(