LB 820-2530 Board with Bad u7000

[jplad]

Looking at a 2009 macbook pro LB 820-2530.
No light on charger

no ppbus_G3H

u7000 pin resistance on:
17/18 => 20.7
27/28=> 20.5

voltage on...
pin 1 = 16.78v
pin 2 = 16.78v
pin 3 = 4.02v
pin 19 = 5v
pin 20 = 5v

pin 21,23,24 =0.7v
ping 25 = 4.5V

Need to replace U7000 as does not appear to be working.

Will a u7000 on old 2011 820-2532-A be compatible?

 

[2informaticos]

First of all, welcome to the forum!

Both 820-2530/32 use the same ISL6258 chip.

 

[jplad]

Replaced u7000 and now getting steady green light. 12.3V on PPBUS_G3H which seems a little low. Board not connected to battery.
diode mode(red probe on GND)
SMBUS_SMC_BSA_SCL = 5.2
SMBUS_SMC_BSA_SDA = 5.3

Voltage...
SMBUS_SMC_BSA_SCL =3.4v
SMBUS_SMC_BSA_SDA = 3.4v

PP3V3_S5_AVREF_SMC=3.3v.

bad SMC?

 

[2informaticos]

Note that diode mode MUST always be tested with red probe connected to ground.
And do NOT write the "V" at the end of diode mode reading; avoid any confusion with a voltage measurement.

Power must be disconnected before check in diode mode, or ohm scale.
Even better allow 10s, to discharge remanent voltages.

 

[jplad]

My bad on the diode "v" (edited the above) . Just to clarify, for the above diode reading, board was not connected to power.
Could anything else be pulling down the voltage on PPBUS_G3H or is this most likely a bad SMC?

Thanks for the guidance. Much appreciated!

 

[2informaticos]

Can we get correct diode mode readings on SCL/SDA lines?

 

[jplad]

SMBUS_SMC_BSA_SCL = 0.519
SMBUS_SMC_BSA_SDA = 0.535

Thank you.

 

[2informaticos]

Too big difference there.
Did you check when U7000 was removed?

Remove D6950 and check again.
First, disconnect BIL and check.

 

[jplad]

I did not check when u7000 was removed.
BIL not connected.

With D6950 removed...

SMBUS_SMC_BSA_SCL = 0.517
SMBUS_SMC_BSA_SDA = 0.532

 

[2informaticos]

Still no good values.
Remove C6952/53 and test.
If still big difference, then remove U7000 and check again.
If no good, SMC is the last option.

 

[jplad]

I removed C6952/53 and measurements dropped slightly.
SMBUS_SMC_BSA_SCL = 0.510
SMBUS_SMC_BSA_SDA = 0.522

Removed U7000 now getting:

SMBUS_SMC_BSA_SCL = 0.597
SMBUS_SMC_BSA_SDA = 0.698

 

[2informaticos]

You stil have big difference.
You may have bad solder, or broken trace for SDA line (to SMC).

BTW, when you remove something, values must increase.
Not for caps removing, but let time the board cools down.

 

[jplad]

I noticed the values changing between hot and cool board. I removed U7000 last night and checked it this morning.
I'll continue playing with this, but being an old board, I'll work on it when I have time.

My biggest issue is not being able to compare this to a working board.

Appreciate your help and guidance. Thank you!

 

[2informaticos]

But you had 2532 board, no?

 

[jplad]

Yes, old board with GPU issue. I've been pulling components from it for last few months for other repairs.