SMC Issue on MBP 13 - Hardware Troubleshooting Guide

[U-234]

Fuse is good so are the FETS
I have the complete G3Hot circuit working.

There are more FETS you can check, Pg 66 'power FETS' I would take measurements and see. If ok, I would go to the next circuit.

For instance, this way I discovered and ruled out some other good working circuits like the battery ISL charging circuit. Now, in my case no post, no beep i discovered issues with these two circuits (High Voltage Switch and 15V Boost Regulator. It takes lot of time to troubleshoot it, definately time consuming, so patiance is the key

 

[geogecko]

Turns out my friends was his power adapter. Borrowed another adapter, and his worked just fine. Are the $80 adapters really the best way to go? The ones on Amazon and eBay seem to be fake or unreliable.

So, with all this available knowledge, it seems like you could buy a damaged one, and restore it. What do you typically look for when looking for a damaged one? Is water damage preferable over some other kind of damage?

 

[macdiver]

Hi Guys, i have a very similar problem to some of you that perhaps you can help me diagnose.

Machine: MacBook Pro Unibody 2009 2.26GHz 13" (NO Water damage)
Symptoms: Dead. No Fan, No Sound...
SMC reset has no affect
Connecting magsafe does not light indicator on magsafe plug.

Voltage between + and ground on the underside of the DC-IN board I see 16.8V

Voltage on Fuse near DC-in 16.8V

Voltage on Fuse near Battery Connector 0V

G3HOT 1.5V

Any suggestions on further diagnostics?

Thanks

 

[mac-n-sauce]

Hi Guys, i have a very similar problem to some of you that perhaps you can help me diagnose.

Machine: MacBook Pro Unibody 2009 2.26GHz 13" (NO Water damage)
Symptoms: Dead. No Fan, No Sound...
SMC reset has no affect
Connecting magsafe does not light indicator on magsafe plug.

Voltage between + and ground on the underside of the DC-IN board I see 16.8V

Voltage on Fuse near DC-in 16.8V

Voltage on Fuse near Battery Connector 0V

G3HOT 1.5V

Any suggestions on further diagnostics?

Thanks

That battery fuse should not be 0v did you check for continuity? The fuse could be blown.

Find out why you are not getting G3HOT @3.4v
Look at the G3HOT circuit. It is on page 58 of the schematic. Check D6905 and U6990 should have 3.42v

 

[mac-n-sauce]

There are more FETS you can check, Pg 66 'power FETS' I would take measurements and see. If ok, I would go to the next circuit.

For instance, this way I discovered and ruled out some other good working circuits like the battery ISL charging circuit. Now, in my case no post, no beep i discovered issues with these two circuits (High Voltage Switch and 15V Boost Regulator. It takes lot of time to troubleshoot it, definately time consuming, so patiance is the key

They all seem to be reading correctly.

I checked the CPUVTT power supply page 63 and I am only getting .91v instead of the 1.05v. Could that be the issue?

 

[macdiver]

That battery fuse should not be 0v did you check for continuity? The fuse could be blown.

Find out why you are not getting G3HOT @3.4v
Look at the G3HOT circuit. It is on page 58 of the schematic. Check D6905 and U6990 should have 3.42v

The fuse is O.K.

Reading the Thread i was able to find the U6990/LT3470 (thanks to mac-n-sauce) but not the D6905. I am guessing it is near the LT3470 (labeled SCJRPU)

Working on the attached picture from mac-n-sauce i have added my measurements.

On the first file are the measurements as described on my first Post (no light on magsafe etc.)

On the second file are the measurements after accidently short-circuit (sorry for my bad English) Pin1 and Pin2 on the D6905 (0.15V and 1.6V), where the macsafe light turned on green.

When i disconnect the magsafe (and reconnect it) the macbook comes to the first state (no light on magsafe etc.)

I was not able to get measurements from LT3470.

Thank you for helping me out.

 

[mac-n-sauce]

The fuse is O.K.

Reading the Thread i was able to find the U6990/LT3470 (thanks to mac-n-sauce) but not the D6905. I am guessing it is near the LT3470 (labeled SCJRPU)

Working on the attached picture from mac-n-sauce i have added my measurements.

On the first file are the measurements as described on my first Post (no light on magsafe etc.)

On the second file are the measurements after accidently short-circuit (sorry for my bad English) Pin1 and Pin2 on the D6905 (0.15V and 1.6V), where the macsafe light turned on green.

When i disconnect the magsafe (and reconnect it) the macbook comes to the first state (no light on magsafe etc.)

I was not able to get measurements from LT3470.

Thank you for helping me out.

Ok, the 47 ohm resistor should have almost identical voltage in and out.
Also, unplug the magsafe charger and use your multimeter to test the ohms on that 47 ohm resistor. With your meter on the lowest setting in the ohm scale it should read 47 because there is nothing else on the circuit. My guess based on your voltages is that it is bad. In my photo that you used you can see that mine is burnt. You should be able to clearly 470 on it.

I am attaching a photo of the D6905 and the approximate values you should have. This is located on the top of the board opposite the LT3470. The diode numbers will be effected by the bad 47 ohm resistor though.
The big yellow part with 3.4v is the C6990 capacitor

 

[macdiver]

Ok, the 47 ohm resistor should have almost identical voltage in and out.
Also, unplug the magsafe charger and use your multimeter to test the ohms on that 47 ohm resistor. With your meter on the lowest setting in the ohm scale it should read 47 because there is nothing else on the circuit. My guess based on your voltages is that it is bad. In my photo that you used you can see that mine is burnt. You should be able to clearly 470 on it.

With magsafe and battery unplugged i get 53.7Ω

Following the picture i have:

1.6V instead of 3.4V

3.5V on Pin 1
0.22 on Pin 3
2.5V on Pins 5/4

 

[mac-n-sauce]

With magsafe and battery unplugged i get 53.7Ω

Following the picture i have:

1.6V instead of 3.4V

3.5V on Pin 1
0.22 on Pin 3
2.5V on Pins 5/4

The resistor is only allowed a max 5% variance which is 2.35ohm
It is bad.

 

[cmdrdata]

The resistor is only allowed a max 5% variance which is 2.35ohm
It is bad.

R6905 being off by a small amount although outside the 5% tolerance in this circuit is NOT the problem. That resistor is just used to drop the input voltage from magsafe to be slightly lower so as not to exceed the LT3470's max input level.

 

[Bonn55ie]

the problem does not seem to all that common.

 

[mac-n-sauce]

R6905 being off by a small amount although outside the 5% tolerance in this circuit is NOT the problem. That resistor is just used to drop the input voltage from magsafe to be slightly lower so as not to exceed the LT3470's max input level.

Well his D6905 diode readings are so off. I figured just start at the beginning. I defer to your knowledge for sure.

Did you get a chance to look at my post #880

I am stuck!!
G3Hot is good, but still can not power on or get green light on magsafe.

----------

the problem does not seem to all that common.
Image

Which one?

 

[mac-n-sauce]

Does anyone know what pin location is vout on the ISL6259/ISL6258?

 

[cmdrdata]

Does anyone know what pin location is vout on the ISL6259/ISL6258?

Did you look at my post #836? Also, I don't know what you meant by VOUT on that chip as it is a charger controller with many output none with that name. The key output of this chip are the UGATE and LGATE signals that controls the generation of 12v via the power FETs. This 12v (nominal) is the system power that also charge the battery when all other conditions are met.

Generally, as dadioh mentioned many posts ago, if you have G3HOT and 12v at the fuse near the battery connector, then the "system not powering up" is probably further down the line, e.g., ALL SYETEM_POWER_GOOD (not the exact name but something like that in the schematic, name wise).

 

[U-234]

Does anyone know what pin location is vout on the ISL6259/ISL6258?

I agree with cmdrdate if you getting 12V on the white fuse near the battery then you have to go further the line (look at my screenshot) "to System"

The fuse is the last poing 'before" it goes to system.

Your issue appears to be beyond PBus Supply and Battery Charger circuit.

I had a board few months ago with no power at all, but I was getting 0V on the battery fuse thus I had some fixing to do 'before' it went to system.

 

[mac-n-sauce]

I agree with cmdrdate if you getting 12V on the white fuse near the battery then you have to go further the line (look at my screenshot) "to System"

The fuse is the last poing 'before" it goes to system.

Your issue appears to be beyond PBus Supply and Battery Charger circuit.

I had a board few months ago with no power at all, but I was getting 0V on the battery fuse thus I had some fixing to do 'before' it went to system.

Ok, I messed up in my description.
The fuse is good, but not getting 12v.
So I have g3hot but no 12v

 

[U-234]

Ok, I messed up in my description.
The fuse is good, but not getting 12v.
So I have g3hot but no 12v

Don't bother attempting to turn your laptop until you will see 12V on that fuse. Now, I would concentrate on your ISL, what are you getting on LGATE and UGATE? Also, i believe Dadioh or cmdrdate posted some values earlier so you can compare it.

 

[mac-n-sauce]

Don't bother attempting to turn your laptop until you will see 12V on that fuse. Now, I would concentrate on your ISL, what are you getting on LGATE and UGATE? Also, i believe Dadioh or cmdrdate posted some values earlier so you can compare it.

I am getting nothing on those two points on first computer
Actually I have two computers with the same problem
The second one has Lgate pin 21 = 6.78v
Ugate pin 24 = 4.6v

I think it might help to understand how the power flows through this system.
As I look at the Power System Architecture page, it has numbers and letters with circles on them. Do you know what they represent?
What I am trying to figure out: What order do you check circuits? If the G3HOT is good then?
If the G3HOT is bad, start there, then? etc.

 

[U-234]

I am getting nothing on those two points on first computer
Actually I have two computers with the same problem
The second one has Lgate pin 21 = 6.78v
Ugate pin 24 = 4.6v

I think it might help to understand how the power flows through this system.
As I look at the Power System Architecture page, it has numbers and letters with circles on them. Do you know what they represent?
What I am trying to figure out: What order do you check circuits? If the G3HOT is good then?
If the G3HOT is bad, start there, then? etc.

I would take measurements of all the pins and see where the values are off.

For instance when I measured my Ugate pin 24 i got 12V where Lgate pin 21 was 0V with just battery connected w/o dcin.

Looks like both of your pins are off.

 

[macelek01]

A1181 logic board repairing

Dear Friends,

I'd like to ask for some help.
I have a logic board from a macbook black (A1181, 4.1, 2,4GHZ). This has water damage. The corrosion was cleaned.
After this, it's able to load the battery (the green and orange led indicator is works), but it doesn't power up. When I switch it on, it makes quiet clipping noise.
The fuses are okey. (I measured them, and these have 16,52V.) The G3HOT has 3,42V (from magsafe and battery, too).
I measured the PPBUS_G3H, it has 12,61V. I think this is good enough.
What do you think what should I do to power it up?

Thank's a lot!

 

[macdiver]

O.K.

I have decided to change the

R6905
U6990
D6905

I don't have the necessary equipment, so i searched and found someone with better equipment and more experience, who is willing to try !!!

Where can i order this components ? I prefer Europe...

Thanks

 

[Wickeido]

Hello,

I'm working on a A1278 820-2879 13" MacBook. It was water damaged. Cleaned all the board, and now I get only a very dim green light.

Testing the board I've seen that the Q7085 FET has voltage on source and gate, but not in Drain. Drain is 0.3v. Is this due to a faulty FET or is there another component controlling the Drain?

Could I overpass the FET and connect the 18,5 to the Drain to see if the system boots, or it will destroy something?

Thank you for any help!

Wickeido

 

[macdiver]

Can someone give me links for the

R6905
U6990
D6905

components from digikey PLEASE!!!

Thanks

 

[mac-n-sauce]

Can someone give me links for the

R6905
U6990
D6905

components from digikey PLEASE!!!

Thanks

Just go to digikey and type in lt3470 for the u6990
The r6905 is part#311-47bct-nd
can't help you with diode (d6905)
Probably the U6905 that is bad.
digikey.com

 

[macdiver]

Just go to digikey and type in lt3470 for the u6990
The r6905 is part#311-47bct-nd
can't help you with diode (d6905)
Probably the U6905 that is bad.
digikey.com

I have already searched for the lt3470, but the results are more then one. Witch one is the right?

Thank you, once again.