See how we repaired a dead Dell Venue 8 Tablet.
Disclaimer: do not copy call. It's that simple. The processes I have used to repair this device can cause serious injury to the person or permanent damage to the device. If you have a faulty electrical device then call me on 01252 962898. Please do not attempt anything in this blog. iLogix Computer Solutions can not be held accountable or liable for any damage to persons or property. This blog is for informational purposes only. It is not a set of instructions.
iLogix Computer Solutions were asked to repair a Dell Venue 8 Tablet, the device would not power on. When we connected it to a power supply we can see it drawing around 1mA (milliamp). That is nowhere near enough, and it tells us the device is not even trying to power on.
The first thing we need to do is dismantle the device. On a Dell Venue 8 Tablet the rear case comes off to expose the system board and battery, we take extra care when removing plastic casing as it cracks very easily. We also need to follow Safe ESD procedures.
ESD means electro static discharge, this means static build up in the environment including on ourselves can be transferred to another object and if the object is sensitive to static it can be come permanent damaged. It's like if you walk across a room and touch someone and they get an electric shock. Safe ESD procedures mean that before we handle electrical components we ground ourselves to ensure we do not make the situation with a faulty device worse. Notice the red mat we use, we are connected to this through a wrist strap.
Once our case is off we remove the system board and remove the shields.
Like I have said in previous blogs the first thing we do is look at what we can see before we look at what we can not. If we examine the system board under a microscope things like corrosion and blown capacitors will stand out.
In this case, however, everything looked ok.
So what now ? The next thing we do is look for shorts. Short circuits are very common on electrical devices and will almost always point us towards the fix. Locating the short is the hard part.
So, what is a short circuit ? A short circuit occurs when an electrical component develops a fault. Electricity loves going to ground and in a short circuit the designed electrical flow stops short of completing a circuit and takes an unintended path to ground. Now when this happens the component with the short gets hot, after all it is taking the electrical flow from the board. Make sense ?
Every capacitor in a circuit has a ground on one side. If we get a multi meter in continuity or diode mode we can test capacitors, if there is a short circuit both sides of the capacitor will be grounded. Thats exactly what happened here.
We now need to see what is getting hot. Remember that the shorted component takes the electrical flow from the circuit which makes it get really hot.
There are a number of methods used to locate the hot spot. The one I use is a voltage injection and then observe the board under a Thermal Camera. I use a Mechanic VC04 Voltage Injector and a Flir One LT Pro that interfaces with an iPhone or iPad.
If we inject voltage into the shorted capacitor we can then look at the board to see what gets hot.
And here we are !! 146 degrees !!
When we look at the board we can see it is a short in one of a memory modules.
So thats the hard part out of the way.
We now need to remove the memory module and replace it. We do this using micro-soldering. I love the smell of solder in the morning !!
We firstly apply soldering flux around the component, soldering flux creates a chemical reaction with the solder and this helps the solder flow nicely. Without it it would be chaos. Flux is the liquid in the photo below. In addition we place heat resistant tape and foil around a plastic flex cable connector, this will prevent us melting it with our soldering iron.
We then apply heat, around 450 degrees to the faulty component. This melts the solder balls under it and allows us to safely lift it off the system board.
The photo below shows the exposed pads and the removed memory module below it.
We next need to clean up the pads under the faulty component. We do this by mixing leaded solder and removing the solder with soldering wick.
We then get a new component and then solder it in place.
iLogix Computer Solutions source components from many resources. My favourite is Farnell and RS in the UK however occasionally we have to use donor boards and Ali Express. This one here was ordered from a factory in China.
We apply new soldering flux, position our component making sure we get the orientation right and then apply hot air from our soldering station. After a a few seconds the solder balls melt under the component and it connects to the pads on the system board.
We clean the board with some IPA (Isopropyl Alcohol) and after reassembly our Dell Venue 8 Tablet now boots.
It's a fix !!!!!
We are also drawing 1.9A, that tells us we have a battery charging and a working tablet.
OK so did that look easy ? don't bet on it.
If you have a faulty Game Console, Mac, PC, Mobile phone or Tablet then call us now. We love computers, we love electronics and we are seriously nerdy. We love making your devices work again, it's what we do. We also drink wayyyyyyy too much coffee but that's IT people in general.
iLogix Computer Solutions - 01252 962898
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