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820-2530 battery not visble for OS X

V

VinceLx2

Member
Hi,
This board is not charging the battery (green light always present) and in OS X it says: Battery not available. If I cut DC IN, the board stops.
I tried with another good battery, same issue.
BATT_POS_F=12.15V
SYS_DETECT_L=0V
SMBUS_BATT_SCL= moving between 34 and 125mV
SMBUS_BATT_SDA= moving between 33 and 108mV
In diode mode, I have 0.48V on pin 1 and 2 of D6950
R5280 and R5281 = 0.9 kohm
What can I check next?
 
V

VinceLx2

Member
Yes, the board is out of the case, just with DC IN, trackpad, Mini display port and HDD on USB.
Values in diode mode on a good board on SMBUS_BATT_SCL and SMBUS_BATT_SDA is 0.52V, so this seems ok
PP3V42_G3H_SMBUS_SMC_BSA=3.42V also ok
On the other hand, on the good board R5280 and R5281 = 2 kohm, and I have 0.9 kohm. So, this means issue on SMC or U7000?
 
2informaticos

2informaticos

Administrator
Staff member
"SMBUS_BATT_SCL= moving between 34 and 125mV
SMBUS_BATT_SDA= moving between 33 and 108mV"
Don't you get 3V there???
 
V

VinceLx2

Member
I confirm I don't have 3V, see attached a photo: it's just a burst of square waves every second
 

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2informaticos

2informaticos

Administrator
Staff member
Better to keep the o-scope for other jobs.

What is the DC voltage showed by DC voltmeter on the SCL/SDA lines of battery bus.
If you don't get 3V (aprox) there, then you have broken trace somewhere.
Check continuity from battery connector to R5280/81.
Do you get 3V at any pin of these resistors?

BTW, check the voltage with charger connected, without battery.
 
V

VinceLx2

Member
What is the DC voltage showed by DC voltmeter on the SCL/SDA lines of battery bus: 0V, with or without battery connected
Check continuity from battery connector to R5280/81: traces are ok, continuity is 1 or 2 ohm
Do you get 3V at any pin of these resistors?: no, I get 0V, the same as at the battery connector.

The trace I showed in the previous post is all I get, either on R5280/81 or on the battery connector (so 0V, just square waves every second)

Can't we assume that the entrances of SCL/SDA lines on SMC or U7000 have an issue? The values of R5280/81 I measure are 0.9 kohm and not 2k, it could be an internal partial short with PP3V42_G3H ?
I checked for water damage around SMC or U7000, seems ok
 
2informaticos

2informaticos

Administrator
Staff member
"Do you get 3V at any pin of these resistors?"
Pay more atention to the questions in the future; you save time.

Very strange to get 0V on both SCL/SDA lines, with 0.480 in diode mode.
Check if R5280/81 are really good; 2K (ohm scale) out of board.
Please be sure your readings are correct.
 
V

VinceLx2

Member
I removed both R5280/81, indeed they are 2 kohm.
I removed U7000, then in diode mode I still have 0.54 and 0.55V on SCL/SDA lines. When I measure resistance where R5280/81 should be, I have 10 kohm
Replaced both R5280/81, voltage on pins 2 remains 0V, without U7000
So, only SMC remains to give these bad values?
 
2informaticos

2informaticos

Administrator
Staff member
This is really strange, with 0.480 in diode mode.
Check the voltage with SMC removed.
First check removing D6950 only.
 
V

VinceLx2

Member
Removed D6950: same story
Then I first simply heat SMC, and I finally got 3.4V on SCL/SDA lines.
Voltage went back to 0V on SDA line and around 1.5V on SCL line after total cooling down, so now assuming an SMC issue.

For the moment I don't have another SMC for this board, So I would like to use it without battery charging option.

So I put back D6950, U7000, but now the board does not start anymore (SMC_ONOFF_L to ground). I could start the board before heating the SMC, even without 3V on SDA/SCL lines. What is going on now?
PPBUS_G3H=0V
On U7000:
1 = 0V
2 = 17.4V
3 = 4.3V
9 = 0V
12 = 3.4V
14 = 3.4V
15 = 0V
17 = 0V
19 = 5.1V
20 = 5.1V
27 = 17.2V

Any idea?
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
"PPBUS_G3H=0V"
What about diode mode to ground?
Be sure didn't knock off any component on U7000 area; pay atention to C7025.
 
V

VinceLx2

Member
Diode mode shows 0.48V. It was U7000 not well soldered, after resoldering I get PPBUS_G3H=12.3V and the board starts.

To know the end of this story I removed SMC, and finally got 3.4V on SDA/SCL lines.

Replaced SMC with fresh solder, and it keeps 3.4V on SDA/SCL lines, PPBUS_G3H=12.6V. And now orange light with a battery, and battery visible in OS X.

Thank you for your support in this old board, very good exercise for me
 
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