Touch 4 Replace Power/Volume Flex Cable - Solder? Asle?
Replaced the screen/digitize
When soldering a new one on, is it just a quick touch to tack it on? Do I have to lay on any solder or just use what is left when I heat the old cable off?
Asle, were you successful?
Hi ggahan, sorry I did not see this post before now. I ordered a new cable and was able to solder it on. I used a small tip on the soldering iron to 450°C (that is the highest my Welder WHS 40D can do). I had to remove the glue on top of the solder points first. Then pulled on the cable (what was left of it connected to the solder points) and loosened one and one point. I then cleaned the points with flux and applied some solder to the holes on the new cable. Then I taped it in place to line up with the solder points. Just a small touch of the soldering iron to each point did the trick. I am frightened to melt something when soldering such small points.
I have repaired many Touch 4gen. and my impression is that this is one fragile piece of electronics. Be very, very careful when you lift the mid plane to avoid ripping the volume/sleep cable and the speaker cable. Remember that the battery is attached with voltage and any metal spudger could shorten the main board so use plastic tools! The connectors seem more fragile than on the iPhones. And the digitizer connector under the main board?? Why, Apple, why?
asle - THANK YOU for your comment...
I had been 100% successful... until now - the ribbon cable is intimidating to me...
I had it all connected (still disassembled) and tested the screen and it all worked... then - in the space of 3 inches - the cable snapped and the screen went white / then black... all the while iTunes was blindly playing random selections of "BTO" and I couldn't make it stop - volume and off buttons weren't working...
...it was abysmal.
Now I'm petrified that the white screen (that went black) means I've fried something...
...I feel bad.
Any suggestions to encourage the idea of going back to the pit?
I've ordered a new ribbon cable - should I be ordering anything else?
Help... this is my "golf" - my stress relief - my things go right 'cuz I fixed it "thing"...
Did I just blow the whole dang thing?
I used a $3 soldering iron from O'reilly auto and successfuly did this by leaving it plugged in for 5 minutes and used capper solder wick to remove the old solder and taped it in place with a piece of scotch tape. after I sprayed it with flux and put a little dab of solder on each point waiting 20 seconds btween solders. I did it though. No blobs crossed voer and crossbridged and the reassembly was a success. If anyone is changing the back out on a touch 4, you will need to do this nomatter what. There is absolutely no way to peel the strip without breaking it. I use super glue to glue it and it works great
Here is a generalization of my method for soldering in a new flex cable.
I always disconnect the + terminal on the battery. Think about it, if you get in their scraping away epoxy, or doing other things, and the logic board is hot, you can cause arching and burn the board up.
1. At the battery, put Kapton tape on any nearby components.
2. Use a dab of flux to remove the epoxy covering the battery contacts. Also use a brush with 92%+ alcohol to remove the flux, and a static-free cloth to dampen up any excess liquid and debris.
3. Cover the neutral and ground with Kapton tape.
4. I set my Weller to about 475, with a chisel tip and clean/tin it.
5. Put a very small drop of flux on the + connector. Use a copper braid and your chisel tip to gently push (toward the battery). You should only be touching the braid for about 2-3 seconds at most, any more and you can lift pads, etc.
6. Once free, stick a piece of Kapton tape under the + battery connector and the + pad on the board.
- Now if you work on the Flex cable and the iron slips (or one of many other things that could cause arching) you don't risk shorting out the logic board.
FLEX CABLE REMOVAL
1. With the bad flex cable still attached. Use flux, alchohol, anti-static wipe to remove any epoxy covering the contacts.
2. Add a very small dab of flux to the contacts, use your chisel and braid pushing away from the board to "suck up" the solder. 2-3 seconds at the most then let it cool. Don't push too hard. You should be able to gently, and I mean gently, lift the cable and let it free itself. If you pull up on the cable too hard, especially with too much heat, you'll defiantly lift a pad and in for a serious headache.
3. Once you have the old cable off, use your braid, flux, alcohol and anti-static wipe to clean the solder pads
SOLDERING THE NEW FLEX CABLE
1. I heat my weller to about 425. And pop on a very fine solder tip, clean, and tin it. I also use 60/40 resin core solder I think it is like .03mm
2. Get your cable lined up and use some Kapton tape (or have someone help) and get your flex cable lined up on top of the solder pads. I use a jewelers loupe to check the alignment.
3. Place the tip of your solder on one side of the flex cables contact then using a very fine solder tip, touch the tip to the other side of metal contact for about 1 second. The heat will suck the solder into the holes. As it does, again, it takes only a second, pull away your excess solder then the iron. The thing to focus on is you want to get "in and out" as fast as you can when you heat the solder. Done right, you will have a perfect shiny bead.
4. Repeat for the last two flex cable contacts.
RE-SOLDER/ATTACH THE BATTERY
At this point you should have no problem removing the kapton tape between the battery + connector and the logic board and soldering it back on. I switch back to the chisel tip for this.
Once everything is complete, I check the iPod. If all is well you can remove all the excess Kapton tape then cut two small strips placing one top of the battery connections and one over the flex cable connections where you have soldered. This will prevent accidental shorts if someone else (or you) repair the device later and accidental let something hit the contacts.
Everyone has their own method, but after killing a few logic boards when I started repairing i*devices I found what works best for me. Your mileage may vary.
Ok people of all ages, I'm going to help everyone out with the soldering issue with the power/volume ribbon cable. First off, forget soldering its too much trouble. Only de-solder the old ribbon cable off the iPod motherboard. Next properly place the ribbon cable on the contacts on the board. And last use a small strip of electrical tape to hold it in place. So if more repairs are needed no worries about ripping the ribbon cable. And that's how a troubleshooting engineer fixes a difficult problem
Now keep in mind if the screen comes up white, just preform a hard boot with the home and power button. If the screen is still white after several try's and the computer recognize the iPod then the screen and digitizer was defective to begin with. (screen replacement)
I hope this help!