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iPhone, iPad, iPod Hardware Repair Hardware Repair discussions for iPhone, iPod , iPad & Apple Products, help, guides. |
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08-01-2017, 06:22 | #1 (permalink) |
Freak Poster Join Date: Mar 2012 Location: Italy
Posts: 219
Member: 1741592 Status: Offline Thanks Meter: 26 | U1700 with missing pads The missing pads are: B3 - USB0_DN that goes to 90_AP_BI_TRISTAR_USB0_N C2 - BRICK_ID that goes to TRISTAR_TO_PMU_USB_BRICKID D3 - SDA that goes to AP_BI_I2C0_SDA D4 - SCL that goes to AP_TO_I2C0_SCL E2 - UART0_TX that goes to AP_TO_TRISTAR_ACC_UART6_TXD (directly under the CPU) E4 - SWITCH_EN that goes to RESET_1V8_L Are all these pads necessary? It's quite difficult to rebuild those pads, because there aren't visible routes, they all go under the top layer. Advices? Thanks |
08-03-2017, 17:02 | #2 (permalink) |
Freak Poster Join Date: Oct 2010
Posts: 134
Member: 1422282 Status: Offline Thanks Meter: 23 | You pulled out too many pads mate, some of them are necessary. So you need to rebuild the pads with jumpers which itself is difficult task cos of too many pads. Sent from my iPhone using Tapatalk |
The Following User Says Thank You to shani1122 For This Useful Post: |
08-04-2017, 09:01 | #3 (permalink) | |
Freak Poster Join Date: Mar 2017
Posts: 387
Member: 2691507 Status: Offline Thanks Meter: 100 | Quote:
difficult to find the foil with no glue, the one with glue is fine just need to scrape glue off. Definitely you need a scope and good iron with .02 mm tip or .001 if you have a hakko. 1 - What I do is to scrape off some board to reveal pad connector (use #11 surgery knife) 2- Solder peace of wire long enough to go to the other side (beyond pad edge) 3- make pad out of copper foil 4- tin pad with solder 5- place pad under the wire 6- run wire on top to the edge 7- use UV green board insulator to glue wire to the edge of the pad (so it will not come off when you heat the board or chip) 8- cure with UV light (make sure green protector is not to high) shave it off a bit after cure if necessary. There you go. I learn how to do that my self after I pulled 4 pads out of a board and then on a Nand... well couple on my early days and don't feel bad, still happening with crazzy black glue Good luck, | |
The Following User Says Thank You to cisco2017 For This Useful Post: |
08-06-2017, 11:58 | #5 (permalink) | ||
Freak Poster Join Date: Mar 2012 Location: Italy
Posts: 219
Member: 1741592 Status: Offline Thanks Meter: 26 | Quote:
Quote:
But those pads doesn't have a visible route around them, the route goes directly under the center of the ripped pad | ||
08-06-2017, 18:44 | #6 (permalink) |
Freak Poster Join Date: Mar 2012 Location: Italy
Posts: 219
Member: 1741592 Status: Offline Thanks Meter: 26 | Hi, this is the actual situation: some pads have been rebuilt, others i scratched the board to find a track (route) where to solder a wire and rebuild the pad. |
08-07-2017, 06:49 | #7 (permalink) | |
Freak Poster Join Date: Mar 2017
Posts: 387
Member: 2691507 Status: Offline Thanks Meter: 100 | Quote:
You need to use a fine point .01 or .02 mm solder to tin that pin like trace with solder (you'll be able to get a pin head amount of solder on it) solder a wire on that trace run the wire out and use green UV PCB insulator to glue the end of that wire to the outside of the trace whole (so it won't move) now you can put a bit more solder on top of that pin head trace (use flux so it flows to it) If you want to make the pad look and have more surface you can add a copper foil made pad on top and cover with solder (not so easy since it will move very easy) Sorry my friend, I'm not a guide writing guy so I'm just helping you with what I can. BTW: another way to get a pad on top of that under ping is to put a copper pad on top, but you MUST put solder on top of that pin trace so it flows with the top pad. Then use UV mask around the pad to keep it in place. | |
The Following User Says Thank You to cisco2017 For This Useful Post: |
08-07-2017, 20:48 | #9 (permalink) |
Freak Poster Join Date: Mar 2012 Location: Italy
Posts: 219
Member: 1741592 Status: Offline Thanks Meter: 26 | ok you're now clear...as you can see in the photo i tried to scratch to find the track. Is there a program that shows the path of the tracks under the top layer? |
08-08-2017, 04:45 | #10 (permalink) | |
Freak Poster Join Date: Mar 2017
Posts: 387
Member: 2691507 Status: Offline Thanks Meter: 100 | Quote:
I was trying to change the color on your pic to see if I can see something there but you have to much flux and it shines. You can do the same, clean with alcohol and you'll get a better view. | |
08-09-2017, 07:54 | #12 (permalink) |
Freak Poster Join Date: Mar 2017
Posts: 387
Member: 2691507 Status: Offline Thanks Meter: 100 | I my self use an Aoyue 968A will upgrade soon, in need of micro tweezers. Don't know your budget you can try the Aoyue 9378 60 Watt Programmable Digital Soldering and on that you can change tips. If too expensive for you then search for that name in Amazon and it will give you more options and different brands, what you are looking for is to be able to change tips and more important to be able to use the more common tips out there Aoyue hakko and then to be able to change temperatures. Aoyou tips cost around $3+ Hakko tips around 11+ SMD soldering you'll need temperatures from 200 C (leaded solder) to 330 C (lead free solder) |
The Following User Says Thank You to cisco2017 For This Useful Post: |
08-10-2017, 03:56 | #14 (permalink) | |
Freak Poster Join Date: Mar 2017
Posts: 387
Member: 2691507 Status: Offline Thanks Meter: 100 | Quote:
First you need to buy low melting solder 130 C mix that with the current solder and wick it out, the low melt will mix and allow you to wick it at low temperature. You can easily remove lead free solder that melts at 230°C when mixed with 130°C solder. then use low solder only to work on those pads, 480°C is a lot of heat, but lucky you it is not making it to the board because of the tip. The micro tips don't have much heat at the tip, you can research that on the net "how solder iron tip works" | |
08-15-2017, 09:00 | #15 (permalink) |
Freak Poster Join Date: Mar 2012 Location: Italy
Posts: 219
Member: 1741592 Status: Offline Thanks Meter: 26 | i used a new method...scratched the "hole" where was the pad, until i find a track or a pin. Then i put some flux and some solder paste, and i use hot air. The solder paste will melt and it will attach to the pin or the track. Then i will check the link using the multimeter (to check if i catched the right track or not), and i will solder a tiny piece of wire to make the pad. After that, i will use some green pcb mask to cover the solder |
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