What’s wrong with this MacBook?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because it wasn’t turning on. The customer had attempted to replace their own keyboard and clean off their motherboard.

How do we fix this issue?

Initial Diagnosis

First, we start off by plugging in a known good DC-In board. We still get no power on the board. Next, we measure the main power rails on the machine, starting with PP3V42_G3H and PPBUS_G3H. PP3V42_G3H gives us 3.42V as it should, and PPBUS_G3H has 0.02V. Next, we measure SMC_BC_ACOK, which is one of the rails required to get a green light on the charger. SMC_BC_ACOK has 0.00V. This rail comes from the U7000 charging IC. After measuring the resistors around the chip, we find that the chip is pulling the lines on R7010 and R7011 to ground.

Repairing the board

With our hot air rework station, we remove the U7000 chip, which is an ISL6259 IC. Next, we tin the pads under this QFN chip, get ourselves a new ISL6259, and replace it. After letting the board cool down, we have fanspin and power to the board.

I can’t fix this myself. How do I get it fixed?

Rossmann Repair Group repairs MacBooks in New York City. Our MacBook Repair is not limited to NYC though, we accept mail-in repairs from virtually anywhere! Visit https://sendyourmacbook.com to start your MacBook repair.

What’s wrong with this MacBook?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because it had no light on the screen. When we shine a light through the back of the screen, we see an image. That means that this machine is displaying an image but has no backlight.

What do we do to fix this?

Diagnosing the circuit

After we confirm that this MacBook has an image, we measure the Backlight Output voltage. Different voltages on the backlight output circuit mean different things. This MacBook has 11.3V on backlight output. Then, we check the enable line for the backlight circuit. which measures 2.7V, which means that it is being told to turn on. These voltages tell us that the backlight circuit is not boosting. The backlight chip on this board is receiving all the required inputs, but not putting out backlight voltage. This means that the chip itself is likely bad.

Repairing the issue

We have discovered that the backlight chip is the likely culprit in this MacBook. Using our hot air station, we remove the chip, wick the pads underneath, and replace the chip. After letting the board cool down, we turn the machine back on. We find that the screen now has backlight and the issues have been resolved.

I can’t fix this myself. How do I get it fixed?

Rossmann Repair Group repairs MacBooks in New York City. Our MacBook Repair is not limited to NYC though, we accept mail-in repairs from virtually anywhere! Visit https://sendyourmacbook.com to start your MacBook repair.

What are the symptoms of this common issue?

This issue is present on Late 2012/Early 2013 model 15″ MacBook Pros that have a GT650M Graphics card. The issue can present itself in several different ways, including sudden shutdowns, kernel panicking, black screening, or just no image on the screen.

What causes this issue?

This is a very common issue on this model of MacBook. The chip responsible for creating GPU Vcore in this machine is called U8900. This chip sends out spikes of 12V into a coil, which averages out to around 0.9V on VCORE. However, the solder joints on U8900 are very suceptible to cracking over time, causing GPU VCORE to drop to 0.6V or lower. This causes the machine to randomly shut down or black screen.

How can I fix this issue?

If you don’t know how to fix it yourself, you can send your MacBook Pro to our store in New York City for our logic board repair service. We offer competitive pricing and expert repairs from all over the world! Click here for our Mail-In MacBook Logic Board Repair Service.

What is the issue?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because the machine would not turn on.

What was causing the issue?

We start off diagnosing this machine by looking at the power rails that need to be present for the machine to turn on. We find that we are missing PP5V_S5. This is created by U7200. After checking the datasheet for U7200, we find that the enable line is not present for U7200, so that chip is probably not the issue. We follow the rail back to find that the SMC is not creating the rail necessary to turn on U7200. After checking to ensure the SMC is getting power, we determine that the SMC is bad.

How do we fix the issue?

We start off by finding a donor board with the same model SMC and programming. Then, we remove the chip from the donor and reball it. We clean up the pads from the old SMC on the problem board and solder our donor SMC to the board.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because the machine would not turn on.

What was causing the issue?

We start off by seeing that there is no green light on the charger. Next, we measure the power rails that are necessary for a green light on the charger, starting out with PP3V42_G3H. This rail gives us 0.00V. Next, we measure voltage drop to ground on PP3V42, which is 0V. This means we have a short to ground on PP3V42. Next, we remove the inductor for PP3V42 to see which side of the board the short is on. After measuring both sides, we find a short on the system side of PP3V42.

How do we fix the issue?

To find the short, we solder a wire to PP3V42 and connect it to our DC power supply. After we turn on the DC power supply, our short goes away. This means that the short was most likely in a capacitor somewhere on PP3V42 that was blown out by the voltage from the power supply. After plugging the board into the charger again, we see that we now have a working machine. This machine will undergo extensive testing after this to ensure there are no other issues, but it looks to be fixed now!

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook Air to our store in New York City for our logic board repair service because it had no backlight.

What was causing the issue?

The first thing we have to check on any MacBook that has no backlight is the Backlight fuse. While the fuse may not be the primary issue, it can give us a general idea of where the issue may be. On this MacBook, the fuse measures Open Line, meaning it has blown. Next, we measure resistance to ground on Backlight Output. Resistance to ground on this line is almost zero ohms. This means that Backlight Output is short to ground, and replacing the fuse will not fix the issue, as it will just blow again because we have a short to ground.

Next, we have to figure out what is causing the short to ground. After visually inspecting the board, we see that the LED driver looks fine and the connector looks fine. However, there are some capacitors that are discolored.

How do we fix the issue?

To fix this machine, we have to clear the short to ground, and then replace the fuse as well. We can conclude that the most likely source of the short to ground is one of the two discolored capacitors that we noticed earlier. After replacing both caps, the short to ground is gone. Next, we replace the backlight fuse. After confirming that the fuse is good, we turn on the machine and see that we now have backlight!

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook to our store in New York City for our logic board repair service because it has no backlight.

What was causing the issue?

The first step to finding the cause of a backlight issue is figuring out what type of failure is causing there to be no backlight, a short to ground or no boosting. In this case, we have no short to ground on backlight output. This means that backlight output is either not boosting, or not getting any power at all. Measuring both sides of the coil, we see that we have 8V on one side and 0.2V on the other side. This tells us that we have a bad backlight coil, as the output on the coil should be much higher than 0.2V.

How do we fix the issue?

We first replace the coil with one from a donor board. After doing this, we see that we are now getting 8V on both sides of the coil. This is still not good enough to produce a backlight. After conducting another visual inspection, we determine that the jumper that we had run to repair a bad feedback trace was not properly soldered. After correctly soldering this jumper, we see that we have backlight again.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook to our store in New York City for our logic board repair service because it has no power.

What was causing the issue?

The first step to diagnosing a MacBook is to go through all the power rails required for the machine to turn on. Since this MacBook has a light on the charger, we know that our PP3V42_G3H rail is present. Next up is PPBUS_G3H. We measure this to be 4.1V. This rail should be somewhere around 12V. This is most likely why our machine isn’t turning on. The first place we look is our U7000 chip, which is the ISL6259. This chip is responsible for creating PPBUS_G3H. Next to U7000, there are some resistors that allow the ISL to sense current. After checking these resistors, we find that they measure OK. However, around the ISL chip we find a corroded via on the charger cell line. This is required for PPBUS to have 12V. CHGR_CELL is going to determine how many “cells” are in the battery – does the chip produce 8.16v, or 12.26v?

How do we fix the issue?

We fix the broken trace with a small micro-jumper across the corroded area. After touching up all the other solder joints and resistors with fresh leaded solder, we measure 12.59V on PPBUS_G3H. Now, the machine has power as it should.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

Below is a list of tools that are recommended by the Rossmann Group:

Microscope – http://www.amazon.com/AmScope-SM-4B-…oom+microscope

Microscope light http://www.amazon.com/AmScope-LED-14…scope+ring+led

Hot air station- Quick 861DW: https://store.rossmanngroup.com/index.php/quick-861dw.html

Soldering station with 2027 iron(big iron) http://www.all-spec.com/products/FX951-66.html

Micro iron – http://www.all-spec.com/products/FM2032-51.html

Tip for standard iron – http://www.all-spec.com/products/T15-JS02.html

Tip for micropencil that I prefer using – http://www.all-spec.com/products/T30-KN.html

Tip for really tiny connectors(ipad mini digitizer) – http://www.all-spec.com/products/T30-I.html

Smoke absorber – http://www.amazon.com/Hakko-FA400-04…/dp/B00FZPSEY4

Ultrasonic cleaner(don’t buy cheap shit it’ll bite you in the ass) – https://store.rossmanngroup.com/index.php/crest-p500h-45-tray.html

Fluid for ultrasonic – use 100 milliliters per gallon of distilled water – http://www.all-spec.com/products/635-022.html

Big jumper wire that is insulated – http://www.amazon.com/Remington-Indu…/dp/B0082CUZBM

Small jumper wire – rip out of old dead macbook pro battery wire(like A1286 internal batteries, the wire connecting it to the board)

JBC CP-2E Micro Tweezers Station http://www.printtec.nl/contents/nl/d…rstations.html

CW3300g from all-spec.com (green stuf for protecting your new made traces)

Probably old but work great :

Fluke 15B multimeter
Fluke Rigid back probe pin set
DS1102E digital oscilloscope 100MHZ

Boardview Software: 

FlexBV from Paul Daniels- NOTE: DOES NOT INCLUDE SCHEMATICS- http://pldaniels.com/flexbv/

Free iPhone Boardview Software- Includes BoardViews- PhoneBoard: https://phoneboard.co

Paid iPhone BoardView Software- ZXW: https://store.ipadrehab.com/ZXW-3-0-INSTANT-ONLINE-License-Code-p93116884

What’s wrong with this MacBook?

This MacBook was sent to us for our MacBook Logic Board Repair Service in NYC because it didn’t turn on.

How can we fix the issue?

Initial diagnosis

First, we start off by observing that it pulls 200mA from the charger. This indicates that it has either a short on PPBUS_G3H, or the CPU VCORE rail is not present. Next, we check the power rails required for the machine to turn on. PPBUS_G3H, PP5V_S5, PP5V_S4, and PP5V_S0 are all present. However, CPU VCore and ALL_SYS_PWRGD are not present.

Next, we check the schematic to see what creates ALL_SYS_PWRGD, as that is required before VCore can be present. We find all rails normal except PP1V35_S3, which instead of 1.35v is measuring at 2.7V. After checking the area around the chip responsible for that rail, we find that its pins are corroded.

Repairing the Board

This board came in with what we thought was no liquid damage. However, upon inspection of U7400, we found some corrosion around the pins. This chip is on the PP1v35_S3 rail, which is measuring the incorrect voltage. This means that this chip is likely the culprit here. After replacing the chip, we see that the machine now has a green light on the charger and has fanspin, and fanspin means the computer is now functional again.

I can’t fix this myself. How do I get it fixed?

Rossmann Repair Group repairs MacBooks in New York City. Our MacBook Repair is not limited to NYC though, we accept mail-in repairs from virtually anywhere! Visit https://sendyourmacbook.com to start your MacBook repair.

What’s wrong with this MacBook?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because it wasn’t turning on. The customer had attempted to replace their own keyboard and clean off their motherboard.

How do we fix this issue?

Initial Diagnosis

First, we start off by plugging in a known good DC-In board. We still get no power on the board. Next, we measure the main power rails on the machine, starting with PP3V42_G3H and PPBUS_G3H. PP3V42_G3H gives us 3.42V as it should, and PPBUS_G3H has 0.02V. Next, we measure SMC_BC_ACOK, which is one of the rails required to get a green light on the charger. SMC_BC_ACOK has 0.00V. This rail comes from the U7000 charging IC. After measuring the resistors around the chip, we find that the chip is pulling the lines on R7010 and R7011 to ground.

Repairing the board

With our hot air rework station, we remove the U7000 chip, which is an ISL6259 IC. Next, we tin the pads under this QFN chip, get ourselves a new ISL6259, and replace it. After letting the board cool down, we have fanspin and power to the board.

I can’t fix this myself. How do I get it fixed?

Rossmann Repair Group repairs MacBooks in New York City. Our MacBook Repair is not limited to NYC though, we accept mail-in repairs from virtually anywhere! Visit https://sendyourmacbook.com to start your MacBook repair.

What’s wrong with this MacBook?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because it had no light on the screen. When we shine a light through the back of the screen, we see an image. That means that this machine is displaying an image but has no backlight.

What do we do to fix this?

Diagnosing the circuit

After we confirm that this MacBook has an image, we measure the Backlight Output voltage. Different voltages on the backlight output circuit mean different things. This MacBook has 11.3V on backlight output. Then, we check the enable line for the backlight circuit. which measures 2.7V, which means that it is being told to turn on. These voltages tell us that the backlight circuit is not boosting. The backlight chip on this board is receiving all the required inputs, but not putting out backlight voltage. This means that the chip itself is likely bad.

Repairing the issue

We have discovered that the backlight chip is the likely culprit in this MacBook. Using our hot air station, we remove the chip, wick the pads underneath, and replace the chip. After letting the board cool down, we turn the machine back on. We find that the screen now has backlight and the issues have been resolved.

I can’t fix this myself. How do I get it fixed?

Rossmann Repair Group repairs MacBooks in New York City. Our MacBook Repair is not limited to NYC though, we accept mail-in repairs from virtually anywhere! Visit https://sendyourmacbook.com to start your MacBook repair.

What are the symptoms of this common issue?

This issue is present on Late 2012/Early 2013 model 15″ MacBook Pros that have a GT650M Graphics card. The issue can present itself in several different ways, including sudden shutdowns, kernel panicking, black screening, or just no image on the screen.

What causes this issue?

This is a very common issue on this model of MacBook. The chip responsible for creating GPU Vcore in this machine is called U8900. This chip sends out spikes of 12V into a coil, which averages out to around 0.9V on VCORE. However, the solder joints on U8900 are very suceptible to cracking over time, causing GPU VCORE to drop to 0.6V or lower. This causes the machine to randomly shut down or black screen.

How can I fix this issue?

If you don’t know how to fix it yourself, you can send your MacBook Pro to our store in New York City for our logic board repair service. We offer competitive pricing and expert repairs from all over the world! Click here for our Mail-In MacBook Logic Board Repair Service.

What is the issue?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because the machine would not turn on.

What was causing the issue?

We start off diagnosing this machine by looking at the power rails that need to be present for the machine to turn on. We find that we are missing PP5V_S5. This is created by U7200. After checking the datasheet for U7200, we find that the enable line is not present for U7200, so that chip is probably not the issue. We follow the rail back to find that the SMC is not creating the rail necessary to turn on U7200. After checking to ensure the SMC is getting power, we determine that the SMC is bad.

How do we fix the issue?

We start off by finding a donor board with the same model SMC and programming. Then, we remove the chip from the donor and reball it. We clean up the pads from the old SMC on the problem board and solder our donor SMC to the board.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because the machine would not turn on.

What was causing the issue?

We start off by seeing that there is no green light on the charger. Next, we measure the power rails that are necessary for a green light on the charger, starting out with PP3V42_G3H. This rail gives us 0.00V. Next, we measure voltage drop to ground on PP3V42, which is 0V. This means we have a short to ground on PP3V42. Next, we remove the inductor for PP3V42 to see which side of the board the short is on. After measuring both sides, we find a short on the system side of PP3V42.

How do we fix the issue?

To find the short, we solder a wire to PP3V42 and connect it to our DC power supply. After we turn on the DC power supply, our short goes away. This means that the short was most likely in a capacitor somewhere on PP3V42 that was blown out by the voltage from the power supply. After plugging the board into the charger again, we see that we now have a working machine. This machine will undergo extensive testing after this to ensure there are no other issues, but it looks to be fixed now!

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook Air to our store in New York City for our logic board repair service because it had no backlight.

What was causing the issue?

The first thing we have to check on any MacBook that has no backlight is the Backlight fuse. While the fuse may not be the primary issue, it can give us a general idea of where the issue may be. On this MacBook, the fuse measures Open Line, meaning it has blown. Next, we measure resistance to ground on Backlight Output. Resistance to ground on this line is almost zero ohms. This means that Backlight Output is short to ground, and replacing the fuse will not fix the issue, as it will just blow again because we have a short to ground.

Next, we have to figure out what is causing the short to ground. After visually inspecting the board, we see that the LED driver looks fine and the connector looks fine. However, there are some capacitors that are discolored.

How do we fix the issue?

To fix this machine, we have to clear the short to ground, and then replace the fuse as well. We can conclude that the most likely source of the short to ground is one of the two discolored capacitors that we noticed earlier. After replacing both caps, the short to ground is gone. Next, we replace the backlight fuse. After confirming that the fuse is good, we turn on the machine and see that we now have backlight!

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook to our store in New York City for our logic board repair service because it has no backlight.

What was causing the issue?

The first step to finding the cause of a backlight issue is figuring out what type of failure is causing there to be no backlight, a short to ground or no boosting. In this case, we have no short to ground on backlight output. This means that backlight output is either not boosting, or not getting any power at all. Measuring both sides of the coil, we see that we have 8V on one side and 0.2V on the other side. This tells us that we have a bad backlight coil, as the output on the coil should be much higher than 0.2V.

How do we fix the issue?

We first replace the coil with one from a donor board. After doing this, we see that we are now getting 8V on both sides of the coil. This is still not good enough to produce a backlight. After conducting another visual inspection, we determine that the jumper that we had run to repair a bad feedback trace was not properly soldered. After correctly soldering this jumper, we see that we have backlight again.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

What is the issue?

This customer sent in their MacBook to our store in New York City for our logic board repair service because it has no power.

What was causing the issue?

The first step to diagnosing a MacBook is to go through all the power rails required for the machine to turn on. Since this MacBook has a light on the charger, we know that our PP3V42_G3H rail is present. Next up is PPBUS_G3H. We measure this to be 4.1V. This rail should be somewhere around 12V. This is most likely why our machine isn’t turning on. The first place we look is our U7000 chip, which is the ISL6259. This chip is responsible for creating PPBUS_G3H. Next to U7000, there are some resistors that allow the ISL to sense current. After checking these resistors, we find that they measure OK. However, around the ISL chip we find a corroded via on the charger cell line. This is required for PPBUS to have 12V. CHGR_CELL is going to determine how many “cells” are in the battery – does the chip produce 8.16v, or 12.26v?

How do we fix the issue?

We fix the broken trace with a small micro-jumper across the corroded area. After touching up all the other solder joints and resistors with fresh leaded solder, we measure 12.59V on PPBUS_G3H. Now, the machine has power as it should.

What if I can’t fix this myself?

Rossmann Group offers logic board repair services in New York City. We accept Mail-In Repairs from all over the world!

Below is a list of tools that are recommended by the Rossmann Group:

Microscope – http://www.amazon.com/AmScope-SM-4B-…oom+microscope

Microscope light http://www.amazon.com/AmScope-LED-14…scope+ring+led

Hot air station- Quick 861DW: https://store.rossmanngroup.com/index.php/quick-861dw.html

Soldering station with 2027 iron(big iron) http://www.all-spec.com/products/FX951-66.html

Micro iron – http://www.all-spec.com/products/FM2032-51.html

Tip for standard iron – http://www.all-spec.com/products/T15-JS02.html

Tip for micropencil that I prefer using – http://www.all-spec.com/products/T30-KN.html

Tip for really tiny connectors(ipad mini digitizer) – http://www.all-spec.com/products/T30-I.html

Smoke absorber – http://www.amazon.com/Hakko-FA400-04…/dp/B00FZPSEY4

Ultrasonic cleaner(don’t buy cheap shit it’ll bite you in the ass) – https://store.rossmanngroup.com/index.php/crest-p500h-45-tray.html

Fluid for ultrasonic – use 100 milliliters per gallon of distilled water – http://www.all-spec.com/products/635-022.html

Big jumper wire that is insulated – http://www.amazon.com/Remington-Indu…/dp/B0082CUZBM

Small jumper wire – rip out of old dead macbook pro battery wire(like A1286 internal batteries, the wire connecting it to the board)

JBC CP-2E Micro Tweezers Station http://www.printtec.nl/contents/nl/d…rstations.html

CW3300g from all-spec.com (green stuf for protecting your new made traces)

Probably old but work great :

Fluke 15B multimeter
Fluke Rigid back probe pin set
DS1102E digital oscilloscope 100MHZ

Boardview Software: 

FlexBV from Paul Daniels- NOTE: DOES NOT INCLUDE SCHEMATICS- http://pldaniels.com/flexbv/

Free iPhone Boardview Software- Includes BoardViews- PhoneBoard: https://phoneboard.co

Paid iPhone BoardView Software- ZXW: https://store.ipadrehab.com/ZXW-3-0-INSTANT-ONLINE-License-Code-p93116884

We offer Macbook repair in Austin from our storefront - come visit us anytime!

Let's go over another Macbook Repair here - an A1466 that is not turning on. This Macbook Air is giving us a green light on the charger, which tells us that PP3V42_G3H is present. PP3V42_G3H is what allows the onewire circuit to turn on, so the light can turn on.

Since it wasn't turning on, we decided to go down the list of power rails, as listed in the schematic. We found that the machine had PPBUS_G3H on one side of its fuse, but not on the other. We found a short to ground on the side of the fuse that had no power, and saw that the fuse itself was blown. Sad.

We looked around and saw that a capacitor on PPBUS_S5_HS_COMPUTING_ISNS looked wrecked. We scrolled through the schematic and saw that this rail comes from PPBUS_G3H. It goes through a current sensing resistor whose purpose is to be part of a current sensing circuit that will allow the machine to tell how much current every component on PPBUS_S5_HS_COMPUTING_ISNS is using. This explains how a short circuit on PPBUS_S5_HS_COMPUTING_ISNS  can affect PPBUS_G3H.

We removed the ailing cap, clearing the short circuit. Now, the fuse is ready to be replaced. Replacing the fuse would do nothing, as it would simply blow again as a result of the cap short to ground. After replacing both, the machine turns on and takes a healthy 500+ mA - fanspin has been achieved.

The post A1466 Macbook Air logic board repair in Austin - short circuit case. appeared first on Rossmann Repair Group.