Dear all,
I have spent some time disassembling my Nexus 5 and I found that the shielding cover that faces the die-casting has a strange "gold" tape on it (cf. picture enclosed).
I am curious, does anyone know what is it ? Is it a "high" thermal conductivity material that send the heat to the die-casting ? Or is is electrically non-conductive material that avoid leakage ?
I am a bit concerned because if it is for heat transfer, why not putting something on the CPU too ?
Thx for your feedbacks.
fredo490 said:
Dear all,
I have spent some time disassembling my Nexus 5 and I found that the shielding cover that faces the die-casting has a strange "gold" tape on it (cf. picture enclosed).
I am curious, does anyone know what is it ? Is it a "high" thermal conductivity material that send the heat to the die-casting ? Or is is electrically non-conductive material that avoid leakage ?
I am a bit concerned because if it is for heat transfer, why not putting something on the CPU too ?
Thx for your feedbacks.
Click to expand...
Click to collapse
In the service manual it descripted as "Can Assembly,Shield" and the clips of it named as "SMT Boss / Screw / Shield can frame"
The best person to ask would be @AdamOutler. Can you give any insight?
Woven copper tape is both thermally and electrically conductive. Its been a while since I looked inside mine, so I don't really remember it.
Those schematics are funny though.. Ground connected to pin 1... 25 times
AdamOutler said:
Woven copper tape is both thermally and electrically conductive. Its been a while since I looked inside mine, so I don't really remember it.
Those schematics are funny though.. Ground connected to pin 1... 25 times
Click to expand...
Click to collapse
Thanks!
AdamOutler said:
Woven copper tape is both thermally and electrically conductive. Its been a while since I looked inside mine, so I don't really remember it.
Click to expand...
Click to collapse
So it is a copper tape, thanks for the info. But why is the color so "yellow"? It doesn't actually look like copper.
There is still a thing that I don't understand: the hot spot should be the CPU, why not contacting it to the die casting instead of the shielding cover ?! To me, there is something that doesn't really make sense in this design.
Edit: interesting enough, it seems that the LG G3 uses the same concept (cf. enclosed). Die casting in the middle with this "gold" tape on the shielding cover. It seems to be a reference design for LG.
AdamOutler said:
Woven copper tape is both thermally and electrically conductive. Its been a while since I looked inside mine, so I don't really remember it.
Click to expand...
Click to collapse
We use this stuff at work for RF gaskets for EMC. Here's an example: LeaderTech SF030PCU-CA
My guess is that it's to complete the EMI shield around the cutouts for the SoC and the couple of other parts poking through. Look at the mill-out where the PCB sits on the chassis for the SoC. By doing this, they can shave off a mm or two on the phone.
Those schematics are funny though.. Ground connected to pin 1... 25 times
Click to expand...
Click to collapse
Those are all the ground points on the board that aren't part of components. Like screw holes, friction ground contacts, and the shield can. Standard stuff to throw odds and ends that don't make sense elsewhere in the schematic on a single page. On some of the stuff I work on, with hundreds of 11x17 pages for a single board, it's not uncommon to have pages dedicated to holes, bypass caps, and mechanical stuff, all with no regard to pin numbers.
fredo490 said:
So it is a copper tape, thanks for the info. But why is the color so "yellow"? It doesn't actually look like copper.
Click to expand...
Click to collapse
Probably some sort of alloy, nickel/copper. See the link above. Pure copper would corrode too easily.
There is still a thing that I don't understand: the hot spot should be the CPU, why not contacting it to the die casting instead of the shielding cover ?! To me, there is something that doesn't really make sense in this design..
Click to expand...
Click to collapse
Ah, a common misconception about chip packaging.
High power chips like PC CPUs need a lot of heat pulled away from them quickly, and the most efficient way is by facing the back of the die away from the package PCB so a heatsink can be slapped on top. These always are left open-top or have a heat spreader of some sort.
But for most chips, the back of the die is bonded to the package PCB (or leadframe) and bond wires used to jumper the die to the package. For chips that need to be cooled, there are dozens or hundreds of vias in the package PCB (metal plated holes through the PCB) and BGA pads on the other sides of the vias. These are called thermals, and conduct heat from the chip die to pads on the BGA. If you look at the back of a typical BGA, these show up as a separated square array of pads in the middle.
The designer of the PCB that uses this chip will design in thermals between the BGA thermal pads and the ground layer(s). The ground layers are nearly solid sheets of copper, and the thermal vias let it act as a heat spreader.
Also, the SoC in the N5 is a multi-chip package (MCP) and has a second BGA with the DRAM sitting on top of the Snapdragon BGA. The Snapdragon BGA PCB has solder balls on top that make contact with the DRAM BGA. It's all covered in rich creamy epoxy, which isn't all that good at conducting heat.
All this leads up to the top of the Snapdragon 800 package being the least useful place to try pulling away heat.
pokey9000 said:
Those are all the ground points on the board that aren't part of components. Like screw holes, friction ground contacts, and the shield can. Standard stuff to throw odds and ends that don't make sense elsewhere in the schematic on a single page. On some of the stuff I work on, with hundreds of 11x17 pages for a single board, it's not uncommon to have pages dedicated to holes, bypass caps, and mechanical stuff, all with no regard to pin numbers.
Click to expand...
Click to collapse
Believe me, I've worked with plenty of schematics before. I just find it funny that they would label chasis ground as pin 1. Generally that's just ground. Someone obviously had too much time on their hands, considering its an EM shield being called pin 1.
AdamOutler said:
Believe me, I've worked with plenty of schematics before. I just find it funny that they would label chasis ground as pin 1. Generally that's just ground. Someone obviously had too much time on their hands, considering its an EM shield being called pin 1.
Click to expand...
Click to collapse
I think it depends on the EDA tool and the whim of the library maintainer. From the little symbol creation I've done in KiCAD I think pin number visibility can be turned off for a symbol. I'm looking right now at one of our designs, and half the page is plated drill holes, each numbered pin 1. What's better, on the same page is a single high current screw terminal with 4 leads holding it to the board. It's one solid piece of metal, but the symbol shows pins 1-4.
fredo490 said:
Dear all,
I have spent some time disassembling my Nexus 5 and I found that the shielding cover that faces the die-casting has a strange "gold" tape on it (cf. picture enclosed).
I am curious, does anyone know what is it ? Is it a "high" thermal conductivity material that send the heat to the die-casting ? Or is is electrically non-conductive material that avoid leakage ?
I am a bit concerned because if it is for heat transfer, why not putting something on the CPU too ?
Thx for your feedbacks.
Click to expand...
Click to collapse
Going slightly off topic, but could you say if there's something such as a warranty sticker when you open your Nexus to tell that it has been opened?
Thanks in advanced.
ImSoBored said:
Going slightly off topic, but could you say if there's something such as a warranty sticker when you open your Nexus to tell that it has been opened?
Thanks in advanced.
Click to expand...
Click to collapse
I didn't find any warranty sticker in mine. However, it is quite obvious to find if the device has been opened because of the tape holding the back cover. It is almost impossible to open and close it without "damaging" the tape.
fredo490 said:
I didn't find any warranty sticker in mine. However, it is quite obvious to find if the device has been opened because of the tape holding the back cover. It is almost impossible to open and close it without "damaging" the tape.
Click to expand...
Click to collapse
Oh, guess I'll have to wait till my warranty is gone. Still more than one year to go... Thanks btw
Hey folks, Doing my screen replacement on my N5 and got sloppy. Gyroscope chip popped off camera unit.
Should i just order a new camera unit, or is there a way to re-adhere this thing?
See picture.
thanks for your help all
You can resolder it with heat gun
Get a new one. Unless your soldering skill is above adverage
SENT BY ENTANGLEMENT
No not that skilled. Just placed an order for a new one. Thanks folks
So if my gyroscope is not working, I should order an entire camera unit?
These chips are surface mounted. You'll need to add solder paste to each individual copper plating then place the chip on top correctly. Then you'll need to apply heat evenly for it to solder back together. You could do this using an oven if you remove the lens and flex cable. Just remember to place the IC the right way on the board and don't short-circuit anything.
It's much harder than it sounds if you want to do it right. I used to do this for a living and I use $20,000+ machinery to do it.
My display damaged and i wanna to ask you smth guys.
How difficulty is it to change it by myself?
I watch this video "
" and i concluded its pretty easy to change it. But the only tool i dont have is the heatgun the other tools i can buy.
Tell me your opinion. Is it easy to do?
Can't tell if it's easy, but in other situations that I needed a heat gun and didn't have one, I used a hair dryer, which is way more common to have at home, or at least easier to borrow from a neighbor or something like that
Watch tear down and repair vids.
If a repair shop will let you watch them do it.
ESD, learn and understand what it is. Discreet components ie the display and mobo are very susceptible to it out of circuit.
Bare minimum protection is a bare wood surface to work on and a relative room humidity of 50% or better. A earth grounded ESD mat and wrist strap is best
Disconnect the battery as soon as possible in the disassembly process. Discharge below 40% if possible before starting.
Have all the drivers, picks, fine precision tweezers, and tools needed. Excellent light and a 2X or so optical visor be nice.
Inspect for additional damage*.
Have a set of OEM seals and now's a good time to replace the battery if it's performance has noticably dropped.
Take pictures disassembling if needed. It must be put back together exactly as it was.
Do Not over torgue screws... less is better.
Be very careful not to damage the ribbon microconnectors.
Take your time, no rush.
*any impact that can break the display or bend the frame can damage the mobo. High G loads or direct impacts can damage chipsets internally, fracture solder joints and internally damaged multilayered mobo PCB internal traces.
I did it three days ago, bc my mix 3 had contact with water.
Its kind of easy to do with a hairdryer and a small plastic tool.
The hardest part is to glue it back together.
(But I have to say my screen didn't work afterwards. The expert in the phone repair store said its maybe a problem on the motherboard)
slowmotion11 said:
I did it three days ago, bc my mix 3 had contact with water.
Its kind of easy to do with a hairdryer and a small plastic tool.
The hardest part is to glue it back together.
(But I have to say my screen didn't work afterwards. The expert in the phone repair store said its maybe a problem on the motherboard)
Click to expand...
Click to collapse
If the battery isn't promptly removed and especially if it's not immediately powered down the current can cause corrosion and short out circuits. The power section is particularly vulnerable. Try again, inspect mobo and the ribbon connectors for signs of corrosion and moisture. Use bright light and magnification.
Is it completely dry? A good soaking with anhydrous isopropyl will help remove hidden water. Again dry completely afterwards. Getting the underside of BGA chipsets dry is imperative.
The micro connectors tend to trap moisture too.
Careful use of compressed air can be very useful but the key word here is careful. Don't stick a nozzle with 100 psi an inch or two from the mobo! Either use low pressure clean, dry air or back it up for high pressure air.
Use your best judgment... it's a bit of an art.
After you dry it as good as possible let it sit in a warm, dry room with a fan on it. Complete drying may take days without disassembly.
Thank you for the tips! I will try it like you described
The same is true with flooded cars, promptly pulling the battery can limit the damage even save the vehicle.
Be wary on flood damage vehicles for sale now, always check for water lines/marks
Most will suffer impossible electrical problems forever. Brine water always kills...
I dropped my Samsung A30 recently which broke the screen. Having replaced the full screen with a new one, I’m still having issues vertical lines across the screen, any thoughts on what it could be?
Could it be an issue with an alignment or do I need to replace some other parts?
Carefully check the display ribbon cable and pins for any damage. Replace if any is found. Make sure they are clean and completely seated. Inspect the mobo for any signs of damage. Assemble it exactly as it was before.
Likely the only other thing left is the mobo assuming the display is good.
You can try clearing the cache, a factory reset or reflashing to the same rom. However chances are if the data was corrupted it's because of mobo damage. If so using another compatible 3rd party rom -may- bypass the damage*.
Always use a good case to protect the mobo from unsurvivable high G loading or direct physical damage from drops.
*try gently flexing the mobo and putting slight pressure on the chipset with it on. The chipsets are BGA with the solder pads on the bottom and are sensitive to board flexing and high G loads. If one or more of those solder joints are cracked the only way to repair is with a hot air station and a lot of skill. A visible fracture solder joint on a surface mount cap or resistor, etc can be repaired... with the right skillset and tools including a good temperature controlled soldering iron.
blackhawk said:
Carefully check the display ribbon cable and pins for any damage. Replace if any is found. Make sure they are clean and completely seated. Inspect the mobo for any signs of damage. Assemble it exactly as it was before.
Likely the only other thing left is the mobo assuming the display is good.
You can try clearing the cache, a factory reset or reflashing to the same rom. However chances are if the data was corrupted it's because of mobo damage.
Always use a good case to protect the mobo from unsurvivable high G loading or direct physical damage from drops.
Click to expand...
Click to collapse
Thanks for the direction, I’ll attempt the above
AHuss123 said:
Thanks for the direction, I’ll attempt the above
Click to expand...
Click to collapse
You're welcome. I added to that post.
Use good light and a magnifying aid to inspect it.
Take your time...
Hello! I have a Samsung A32 5G and it won't turn on unless I apply pressure on the ribbon cable. How can I find out if the cable or the connector on the motherboard not working.
Use a pencil eraser to gently poke different spots to try to provoke a response to help isolate the area. Use a good light source and magnification to try and spot solder fractures on the mobo.
If it suffered drops with no case it maybe a mobo failure. The BGA chipsets are intolerant to board flexing and high G loading... a good case makes impacts survivable by reducing both.