Help/suggestion soldering flex cable

[wannabe]

Well i was attempting to change the LCD screen on my Sony Xperia Z ultra when i accidentally damaged the flex cable connection to the motherboard. I found the same flex cable being sold for $5 on amazon so finding a replacement isn't an issue, problem is it's tiny and i'm not sure what kind of soldering should be used, any suggestions?

I used an AUD coin for reference because i posted it on a local forum before asking here, the coin is (Diameter 20.50 mm)

Motherboard
http://i.imgur.com/PixYTmR.jpg
http://i.imgur.com/gaqPWHa.jpg
http://i.imgur.com/oPbMYMu.jpg

Old cable
http://i.imgur.com/2iZkRYM.jpg

New cable
http://i.imgur.com/HdEF6wc.jpg
http://i.imgur.com/eox2ioh.jpg

Any help or suggestions welcomed.

 

[chopnhack]

Hand soldering will most likely melt the cable assembly. Do you have the ability to use an oven to low heat solder like they do for smt components? I will try to find a video to explain this better. Most tips of soldering irons are 550-700+ deg F.

Reflow.

 

[Bluejets]

I'd be very surprised if it is not a "clip-in" connector.
They can be tricky sometimes so best to look for a video or a manual somewhere on the web.

 

[wannabe]

Hand soldering will most likely melt the cable assembly. Do you have the ability to use an oven to low heat solder like they do for smt components? I will try to find a video to explain this better. Most tips of soldering irons are 550-700+ deg F.

Reflow.

Unfortunately i don't have access to that. but i'd be intrested in seeing a video.

Thanks

 

[wannabe]

I'd be very surprised if it is not a "clip-in" connector.
They can be tricky sometimes so best to look for a video or a manual somewhere on the web.

Most phones do use clip-in connectors but for some reason Sony decided to permanently solder this flex cable connection.

 

[chopnhack]

I edited my previous post, click on "reflow". There is an inexpensive solder paste that has microscopic spheres of solder in a flux paste, you apply it to the areas to be soldered and then "bake". The author of that video went so far as to have a computer controlled heating sequence (presumably a cooling sequence with appropriate ramp up/down periods). You could simply control it with a thermometer and visual checks, you will see the paste melt and for small parts pull the parts to the pads. The solder mask aides in keeping things were they should be. Its pretty cool. Good luck with your repair!

 

[Bluejets]

So the solder connections you are referring to are to the LCD itself?

 

[wannabe]

So the solder connections you are referring to are to the LCD itself?

To the motherboard

 

[wannabe]

I edited my previous post, click on "reflow". There is an inexpensive solder paste that has microscopic spheres of solder in a flux paste, you apply it to the areas to be soldered and then "bake". The author of that video went so far as to have a computer controlled heating sequence (presumably a cooling sequence with appropriate ramp up/down periods). You could simply control it with a thermometer and visual checks, you will see the paste melt and for small parts pull the parts to the pads. The solder mask aides in keeping things were they should be. Its pretty cool. Good luck with your repair!

Thanks for that. it seems like the main issue with this idea or any method is actually getting it aligned properly because some of the lines are almost hair thin.

 

[chopnhack]

Thanks for that. it seems like the main issue with this idea or any method is actually getting it aligned properly because some of the lines are almost hair thin.

Indeed!! I would suggest the reflow method and tape the ribbon in place before putting it in the oven

 

[davenn]

chopnhack's method may work
but in all reality this is going to be somewhere between unlikely and impossible to do at home
Hell, I have even tried repairs like this where I work and have never succeeded

Dave

 

[chopnhack]

Sorry @wannabe - it may not be a feasible repair! @davenn What failed when you tried? Did the reflow heat affect the ribbon? Was it hard to align and keep flat?

 

[davenn]

What failed when you tried? Did the reflow heat affect the ribbon? Was it hard to align and keep flat?

yes and yes, it just turned into a total frustration

my signature line comes to mind in this situation

 

[chopnhack]

Bummer Dave... maybe wannabe will have better luck taking it in for repair.

 

[Bluejets]

Had a mate who used to mod PS2...........until one of the later models came out where the manufacturers were a wake up to what was going on.
One touch with the iron in his normal mod point and 6 legs of the micro popped-up.

When I saw him he was on day two of just trying to pin them back down again......... goes without saying I didn't say a word and quietly left him to it.