Here I demonstrate one basic, low tech method to find a short to ground in a Macbook Pro logic board. I am commonly asked where I went to school to learn this, told I am a genius, etc, and I really want to demystify that. I am not a genius. I am a regular dumbass, just like you, and I often use low tech, low brainpower methods to do my troubleshooting. This is a standard troubleshooting technique we use for our own Macbook logic board repair service.

PPBUS_G3H is the 12.6v the system runs off of. The charger puts in 18 to 19v, and ISL6259 controls two transistors that turn this into 12.6v.

A little backstory so you have a clue wtf is going on to make the 12.6v for PPBUS_G3H, when you look at U7000, Q7035, Q7030.

a) A transistor is nothing but a TRANSFORMING RESISTOR. See here. https://www.youtube.com/watch?v=CkX8SkTgB0g

b) Now that you know that a transistor is just a resistor with a variable resistance, pretend these two transistors are just resistors. They are arranged to act as a voltage divider. See here for information on what a voltage divider does. https://www.youtube.com/watch?v=XxLKfAZrhbM

So these two transistors act as a voltage divider to turn the 18-19v from the charger into 12.6v for the laptop. The transistor’s resistance is regulated by ISL6259.

Now that that is out of the way, the first transistor turns on, quickly notices that it is shorting to ground, and the system turns it the fuck off. When measuring PPBUS_G3H to ground, I get 2 ohms. this means there is a short to ground on the PPBUS_G3H 12.6v line on the board, which is why it is not turning on.

Some component on the board is shorting PPBUS_G3H to ground. But WHICH??? And how do we find out which?

Here’s a basic way to do it. We know that PPBUS_G3H is shorting to ground. This short circuit means that anything we put on PPBUS_G3H shows up on ground. Therefore, if we inject 12v into PPBUS_G3H from another power supply, the 12v will show up on ground. Let’s go ahead and do that. We do that, and 12v is showing up on ground of the board from PPBUS_G3H which is shorted to ground.

What if we tried to power a 12v circuit, and attached the positive rail of this 12v circuit to ground on this board? That would mean 12v would have to be moving through PPBUS_G3H to ground on the logic board THROUGH WHATEVER COMPONENT IS CAUSING THE SHORT. If we put a demanding load on there, such as, 10+ LED lighting strips, that component will get VERY HOT.

Then we feel around the board for the hot component. Once we feel the boiling component, it’s time to remove it and check if the short is still there.

After removing the GPU on this particular board, the short did indeed go away.

The post How to find a short in a Macbook logic board by using your brain. appeared first on Macbook Repair in NYC | 347-552-2258.

I posted this in response to another question on the internet a while back. I figured it was worth a repost on the company blog.

a) There are no fault indications to tell whether a digitier is bad. just get the customer’s password so you can make sure there is touch everywhere.

b) Make sure they know that you will be absolutely SODOMIZING any corner that is dented in. Don’t say anything other than sodomize, or else you open yourself up to “but I didn’t know it was going to look like THIS!!!!”, and bitching when it comes time to pay. Even if it is barely dented, make sure they get that the frame is going to be beaten to shit to make the new digitizer fit in.

c) Beat the frame to shit to make the digitizer fit in. Never try to pop it in around a fucked up frame. This makes it more likely to lift, crack, and fuck up later. It has to sit flat, with no pressure on it.

d) If they really are not going to have a corner when you are done(some get dropped off balconies and are really fucked), tell them to buy a case to protect the corners.

e) Don’t buy cheap shit digitizers. They have phantom touch where it moves on its own, and it won’t appear instantly. It’ll appear a month or two after you fix it and you have to come back. Buy from Jack Telecom, and buy nothing but their highest quality product. Any copy or knockoff crap is going to work like copy or knockoff crap. Don’t be a cheapskate.

f) Don’t buy eBay digitizers. Don’t buy eBay iPad/iPhone/Macbook parts in general. Parts from eBay suck balls.

g) Use good 3M adhesive to hold it down. You don’t want them coming back in a week saying it’s popping up, or even worse, blaming your popping up digitizer/shitty adhesive when they break it again. This stuff is good. Buy 5mm and use two or three strips worth. Thinner is better, it is easier to double or triple up on 5mm tape than it is to cut down 15mm tape. This stuff is good because it comes off evenly when you want to repair it again after they fuck it up again, and it sticks permanently. It won’t pop off. http://www.ebay.com/itm/251507591911?_trksid=p2060778.m2749.l2649&var=550418703012&ssPageName=STRK%3AMEBIDX%3AIT

h) Don’t tape over the wifi/3g antenna on the iPad 2. That is a dick move for the next technician. There is no need to put adheisve over the antenna, it will be just fine and stick down without you doing that. They will break it again, and the next time you fix it, you don’t want to be dealing with removing the glass without ripping the antenna.

i) Don’t rip the antenna, power button flex, or volume flex. Apple has a hard on for having flex cables inbetween the ipad case, the adhesive holding the glass to the case, and the glass. It’s a sick joke intended to piss off repair technicians, but you aren’t going to rip it. By not ripping the flex cables we do not allow Apple to win.

j) Test the power button and volume buttons before you work on the iPad so you can tell people to go fuck themselves when they blame you if their buttons don’t work a week later. It’s common for customers to accuse you of breaking these. These buttons are all made like dogshit on Apple products. While the A & B button on a $100 gameboy from 1996 still work, the flex buttons on a $700 Apple product last about six months before they die. That is WHY there is an entire business based around carpetbagging “technicians” replacing power and volume buttons on these things; they suck THAT bad.

k) Have volume & power flexes as well as 3g & wifi antennas in stock for when you DO rip the cables. They cost under $10 each for good ones. There is no excuse to not have these if you make a living working on this shit. There is no excuse to keep people waiting an extra week because you don’t have some $5 cable outside of you being a cheapskate douche of a business owner.

l) Do not stock volume, power, 3g, or wifi flex cables from eBay. eBay parts suck. Refer to point F.

m) Get a good spudger to get under the glass. Get a GOOD one.

EXAMPLES OF BAD/USELESS SPUDGERS:

http://www.ebay.com/itm/Black-Plastic-Spudger-Stick-Opening-Repair-Tool-For-iPhone-iPod-iPad-PSHP-/311042631616?pt=Other_Tablet_eReader_Accessories&hash=item486b95e7c0

http://www.ebay.com/itm/5x-Metal-Spudger-Stick-Pry-Open-Tool-for-iPhone-4-4S-iPad-iPod-Touch-HTC-Samsung-/351114213526?pt=Other_Tablet_eReader_Accessories&hash=item51c009b896

http://www.ebay.com/itm/Plastic-Pry-Tools-Metal-Spudger-Opener-for-iPad-Galaxy-Tab-Repair-5pc-Set-/131172552864?pt=Other_Tablet_eReader_Accessories&hash=item1e8a7e50a0

EXAMPLES OF GOOD SPUDGERS:

http://www.ebay.com/itm/2x-Metal-Spudger-Pry-Stick-Opening-Repair-Tool-For-iPad-iPhone-iPod-Laptops-USA-/371102409000?pt=Other_Tablet_eReader_Accessories&hash=item56676d6128

The one on the left is good, the one on the right is garbage.

n) Cover your table in paper towels. If your fucking eyelash so much as falls on the metal back of an iPad 2, IT WILL GET SCRATCHED and it will be BLATANT. Most iPads coming into your shop will be so fucked up that no one will ever notice or care even if you stab it for fun; but you will occsionally encounter someone who has kept their iPad in a little bubble, never using it from 2011-2014, who expects to receive it back in that condition. Get some decent paper towels, put them on the table, double up on them and don’t let the glass you’re picking out of the iPad get in these paper towels, or under the iPad, as it will scratch the iPad.

o) Hold the iPad the way YOU want to hold it while fixing it. Fuck lying it flat on a table. If you need to pick it up, tilt it, or whatever to get the spudger in at the right angle to get it in there and get the glass out, DO IT! You need to be comfortable first; not the iPad. I see so many people doing this laying it on the table and reaching over the table to get in at the angle they want. Fuck the iPad’s comfort – worry about YOURS!

p) Heat the spudger and it will go under the glass easier.

q) If you heat the spudger, don’t let it touch the bezel.

r) Sharpen the tip of the spudger every now and then so it gets under the glass easier.

s) Don’t fuck anything up.

Happy fixing!

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I posted this to that 2011 MBP GPU issue facebook page. I figured it was worth a repost here.

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From an employer’s perspective, it is important to hire people who will produce for your business. You’re going to find a lot of employees that come up with excellent reasons as to why they were unable to accomplish a task. What I suggest new employers, managers, & business owners do is avoid judging excuses on their merit.

Hre’s the thing about excuses; they often make sense. Most employees we hire aren’t stupid, but even the ones who are dumb as a rock are crafty enough to come up with plausible sounding reasons for why something is not possible given the current circumstances, or why it should be fair that they be late everyday.

The problem that many employers have is that we do not know how to perform the tasks that the people working under us know how to do. The CEO of a company may know what the effects of good or bad marketing are, but he doesn’t know how to do the marketing. He may have no idea how the engineering department works, but he knows if he hears constant complaints about bugs in new products that they have fallen short somewhere. The CEO doesn’t have to actually know how to engineer the product or how to market it to understand if the people who are supposed to be performing these tasks aren’t doing their job.

Can you imagine how much more difficult it is to gauge whether an excuse makes sense when management doesn’t even understand how to do what you do?

What’s important is to realize patterns. Is this specific failure or shortcoming this employee has something that happens on a regular basis? Take excuses out of the equation and simply look at track record over time. If you don’t believe you have enough time, then give them more time – just make sure it’s in your financial budget to pay them to find out if there is a pattern.

If it’s something that happens rarely or never, even if the excuse is ridiculous, be understanding. However, if one individual has a consistent track record of failure, and you know the excuses are BS; you should act accordingly.

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Apple replaces the screen to the iPhone 6 for $109.

There is a lot of talk in the iDevice repair industry on whether it is ethical or not to take a phone from the customer, then bring it to Apple and have them fix it, while taking a middleman fee of $50 to $100. In a private repair forum I am on, the discussion continues. Here is my opinion – copied and pasted from my post. What are your thoughts?

This is absolutely bottomfeeding shit and will come back to you in a bad way. This is only acceptable if you tell the customer in advance that Apple offers $109 repair to consumers. 

I'm not discouraging being a middleman in every transaction. Sometimes it is appropriate to be a middleman. B2B companies do not wish to deal with end consumers, so they offer discounts to "outlets" that then offer their services to consumers. Assetgenie is a great example - they offer motherboard component level repair to businesses, but do not deal with joe blow who wants his laptop fixed. It's one thing if you have a special deal through a B2B wholesale company that won't deal with the consumer. By all means, milk that relationship. 

However, Apple stores ARE the consumer outlet! They are offering this $109 repair and are set up, targeted, and INTENDED to deal with the end consumer. If you are literally dealing with the company that MADE the device, on a CONSUMER level, and just adding a $70 fee on top of it and you know the end customer is only using you out of ignorance, that is BS.

I always preach to focus on sustainable endeavors you can carry over to other fields. Ripping people off by giving them manufacturer service with a fee added on top is not something you can transfer to another field. The more time you spend doing shit like this, the less time you can spend adding value to your own skillset, and the worse off life will be for you years from now when you need to move onto the "next thing." 

This kind of crap is precisely WHY consumers do not trust technicians, mechanics, doctors, and lawyers. You are only adding to it if you carry on this BS.

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What makes diode mode measurements different from resistance mode measurements?

Diode mode measurements allow me to quickly get an idea of what the entire circuit is doing and compare it to a known working board. Diode mode measurements are very similar to resistance measurements, but they are much faster. Resistance is measured in Ohms, and tells you the resistance between two points in the circuit. Diode mode measurements tell you the voltage drop across two points in the circuit. The difference between diode mode vs. resistance measurements is that diode mode measurements can be performed much quicker. Measuring resistance takes the multimeter a while. Measuring the voltage drop takes less than half a second. It is a much quicker and more accurate way to measure an entire circuit.

How does measuring the voltage drop to ground at different points in the circuit help us?

How does this work? Every circuit has a connection to ground at some point. If the circuit changes in any way, the way it connects to ground will change. So what we do is measure the voltage drop between a specific point in the circuit, and ground. We can then compare these values with a known working device and have an idea of where a problem may lie. Let’s say we’re looking at the output of the LCD screen backlight power rail – I expect 0.521 to 0.546 between output & ground on an LP8550 based board. If I see 0.0 or 0.021, there is a short to ground – too litle resistance to ground. If I see 0.474 to 0.511, experience tells me the feedback via is corroded. If I see 0.521 to 0.546, I know the line is correct, and backlight may not be coming on because of a corroded connector, or a signal not present.

I can also measure the individual pins of a chip to get an idea of where the problem lies.

Measurements will always be a little it different based on the different tolerances of the different components. There is no specific guideline on how to tell EXACTLY where the problem is in a circuit based on these measurements; you will still have to use your brain. However, it can be very useful if you are totally lost – these diode mode measurements make an excellent tool to push your focus in the right direction if you have overlooked something obvious.

Check out a real world application.

Here I take the example of a non-functioning trackpad. I overlooked something simple and silly that I should have checked. I went around each pin of the trackpad connector with my multimeter in diode mode, red probe on ground, black probe on each pin of the connector. Then I compared it to a known working board. One was very far off from every other reading, so I followed along that line extra carefully, and found a missing component on an 18v line! Doh.

This is one of many tools that helps me remain professional.

Doing this type of work, it isn’t about being a genius. It’s about having a methodology that allows you to occasionally be an idiot and still resolve the problem. Professionalism isn’t about always being right, having ESD safe mats, accepting AMEX and never making mistakes. It’s about being able to produce repeatable results for your clients that are positive even when curve balls get thrown into the mix. It’s about finding ways to get around the reality of life. You will make mistakes when you don’t get enough sleep, have a bad day, or just miss something because you’re human. You are not a robot. Diode mode measurements assist me in hitting these curve balls out of the park even when I am having an off day, and contribute to the reputation of my business by keeping my success rate high.

Find the tricks that help you remain professional to a WORTHWHILE definition of professionalism.

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Not relevant much anymore since Apple is covering these failed GPUs for free, but I figure it may be of interest to some how the work is performed. Here you’ll see me remove the old chip, prepare the board for a new chip, and install the new chip.

This process is a bit of a pain in the ass. I wanted this video to be, from front to back, unedited so you can see the entire process. There are so many videos that are completely out of focus, zoomed out, or sped up far past the point of being useful if you are trying to learn. This is NOT one of them!

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If the onewire circuit does not work, the charger will only output limited power to the board, and nothing will work off of the charger. The onewire circuit depends on proper function of the battery charger chip, the SMC, and the two ICs that are utilized in the onewire lines.

Common issues with the onewire circuit are the small, easily burned out vias to the U6901 logic gate that is powered by PP3V42_G3H, and corrosion under the SMC.

See more about the onewire circuit here.

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In the past blog, I discussed the onewire circuit. Here I’d like to talk about a specific power rail, that powers the onewire circuit, and its importance.

The PP3V42_G3H power rail is one of many power rails on a Macbook Pro logic board. ignore the confusing nonsense lik PPV and all that – PP3V42_G3H means 3.42v.

PP3V42_G3H is an important rail because it starts before all the others. It is the only rail that can work off of two different power lines – it can be created by PPBUS_G3H from the battery, when working off of the battery, or the 18.5v rail from the charger when the charger is plugged in.

The onewire circuit, which is the circuit responsible for telling the SMC that the charger is plugged in and allowing the charger to work, runs off of the PP3V42-G3H rail. So obviously it is important that this rail start first. This rail does not have to be on first when using the BATTERY to create PPBUS_G3H, because the battery is always present without onewire protection. However, the PPBUS_G3H rail being created by the charger needs the onewire protection to be active, so thus needs PP3V42_G3H to be present!

Even if your PPBUS_G3H circuit is fully functional with no issues, it will not turn on without the onewire circuit being activated, and the onewire circuit will not be activated without PP3V42_G3H. So, if you have no PPBUS_G3H, stop troubleshooting PPBUS_G3H if you have not yet checked PP3V42_G3H!

PP3V42_G3H is the FIRST rail to check on any system if it has no power. If you have a green light on the charger, you can cross PP3V42_G3H off the list of rails to check as you know it is already working. The green light would not turn on if the onewire circuit were not working, and the onewire circuit would not be working without PP3V42_G3H.

Here is a video on the subject.

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A voltage divider is a series of two resistors one can use to lower an input voltage to your desired voltage. Let’s take the BKL_EN circuit, for example. Many circuits inside of a laptop don’t come on until they see voltage at their enable pin – think of the enable pin like their power switch. The backlight boost circuit runs off of 12 volts; however, most of these chips ask for 2.5-3.5 volts for enable. The backlight circuit has a set of transistors that enable 12v to flow through to it when it receives the proper signals, but no 3v to be found in this circuit!

So, what do we do? Do we create an entirely new circuit along the 3.3v rail that knows to come on when backlight is supposed to come on just to create this BKL_EN 3 volts? No, waste. We use a voltage divider to turn 12v into 3v just for the BKL_EN pin!

Here’s a video demonstrating the concept on an 820-2879 board, on a board we recently repaired under our Macbook logic board repair service.

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One of the common issues is that liquid gets in along the vent and touches the board since there is no protection, and there are components along the vent that are very important. The onewire circuit is what allows the charger to speak to the SMC so it can give it the go-ahead to allow power through to the rest of the computer.

On older machines, the logic gate that allows the PP3V42_G3H power line through to U6900 which allows communication between the charger and the SMC sits on the edge of the board. This via is very tiny, and always dies with minimal amounts of moisture applied. In the above video, I demonstrated a common fix for this issue, and also proposed alternate methods of restoring the via.

For more information on what the onewire circuit is, here is a video dedicated to just that topic.

As usual, we fix these board issues and many more under our Macbook logic board repair service

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Error 53 is something often discussed online, without much information. Some think it is just an issue when you change the home button on an iPhone 6 or 6+.

It isn’t.

You can get error 53’d even with the original home button.

Error 53 is Apple’s way of monopolizing the repair of their products at the expense of the end user.

The post What is error 53? appeared first on Macbook Repair in NYC | 347-552-2258.

In most of my motherboard repair videos, the flux I am using is Amtech NC-559-V2-TF. A lot of people have asked what flux I am using because it makes the job so much easier. Even if I tell you what it is, I have not done the hard part of your job in locating Amtech NC-559-V2-TF! The hard part is finding someone that sells the real thing, not some vaseline or expired king-bo flux in an Amtech container.

The vendors I used to purchase from have all been out of stock, so I decided to do the legwork required to become a distributor. This was successful, and if you click below, you will find it for sale from our mail-in website – authentic, genuine Amtech flux, shipped from New York!

https://mailin.repair/amtech-nc-559-v2-30-cc-16160.html

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Here I go over how we troubleshoot a short to ground on PPBUS_G3H, a main power line on the Macbook Air logic board. Here we have an issue where the CPU vcore circuitry. Many people use the word “short circuit” to describe any type of non-functioning circuit, whether or not it is a short circuit!

Watch this short video to learn from start to finish how we figure out the issue and repair it live on camera.

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This Macbook Pro retina logic board has no output on the internal screen. However, using a displayport to VGA adapter, I was able to get a picture to show upon an external monitor, and I was able to run ASD. ASD gave me an error, displayport symbol error. I investigated the displayport data lines and noticed one had no continuity due to a burned via inside the board.

This is one of those things where you will have people all over the internet telling you it is the lcd cable… but it’s never the LCD cable. It’s that good ol’ wishful thinking that there’s a brainless $4 solution to what is a much larger problem.

The solution here was to dig away until I got to the nub that the in-line capacitor in the displayport data line is soldered to. Since there was no pad left, I put solder and flux on a piece of wire, and did my best to tin the nub. I couldn’t use the soldering iron to solder it, even with the micro soldering iron’s smallest tip, so I put some flux there and used the hot air station to flow the little wire onto the nub. Then, I could solder the capacitor to the wire which was soldered to the nub and huzzah.. PICTURE!!!!

We regularly fix liquid spill damaged Macbook Pros with our Macbook liquid spill damage repair service. Watch how below!

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No appointment is necessary – come by during our open hours and we are happy to help you!

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Just incase anyone doubts!

https://www.reddit.com/user/larossmann  is me

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I see many people pointing to dry boxes, thirsty bags, and other hip new “tools” that supposedly fix liquid damaged devices. The reality of the matter is that a burned out component is a burned out component no matter what you put the device in afterwards!

Look at the pictures below. Besides replacing the broken components & running wires between areas where pathways were destroyed, how else can you imagine fixing this?

Firewire worked perfectly with a crisp image on the screen after our repair!

This board had no firewire and nothing on the screen.. surprising?

I want you to think about this when someone says that for $50 they’ll run your phone through some dry box, drop it into silica gel, or use magic software to get data off a phone that’s been in the ocean. Good ol’ fashioned brains & soldering is how we get data back and make devices work again. It takes a lot of thinking, and a lot of work under a microscope. It also brings the greatest rewards – a reliably functioning device over a long period of time.

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Hinge filler

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