820-2850 dim green light

Chuck60

Member
Hi I recieved this board it had a few issues I replaced isl6259 and tps51125 And a few resistors. Now I have

PPBUSS_G3H =12.5v
PP5V_S5=5v
PP3v3_S5=3.3v
SMC_ONOFF_L =3.42v
SMC_RESET_L =3.42v

U5010
PIN 1 PP3V42_G3H_SMC_CLK_F =3.42v
PIN 7 SMC_CLK_R =1.49v ??
Pin 12 PP3V42_G3H_SMC_CLK_F = 3.42v

The logic board will turn on with battery by shorting power on pads but not with charger. Also when it powers on no cpu activity with mouse or usb. PPVCORE_S0_CPU PIN 1 of C1652 =.878v
And CPU gets warm
 
Last edited:

2informaticos

Administrator
Staff member
Are the mentioned voltages for charger only, no battery?

Be aware, this board only starts with 85W charger, if no battery present.
 

Chuck60

Member
The voltages are without battery present.
I added a few other measurements on the first post

U5010
PIN 1 PP3V42_G3H_SMC_CLK_F =3.42v
PIN 7 SMC_CLK_R =1.49v ??
Pin 12 PP3V42_G3H_SMC_CLK_F = 3.42v
 

2informaticos

Administrator
Staff member
Board still doesn't turn on with original 85W charger alone???

"PIN 7 SMC_CLK_R =1.49v ??"
What do you expect there?
Did you check frequency???
 

Chuck60

Member
No I have two original chargers And this board will not power on.
PIN 7 SMC_CLK_R =1.49v ?? Here I expected 3.3v
Also
I also tested the crystal and it had no voltage on 3pins I will test frequency when I get back

I’m gonna go back over these I think these Lin Which I believe should be 3.3v.

AVREF_SMC=

SMC_XTAL_R =1.49v
 
Last edited:

2informaticos

Administrator
Staff member
Why do insist with DC voltage on a crystal???
If you really want to check it, measure frequency, or check waveform with o-scope.
However, 1.49V points to oscillation is present.

Did you check the power charger reported by an working machine?
Do you still have dim Magsafe light?
 

Chuck60

Member
Yes it works on other machines
And yes it works on other machines
I will check with oscilloscope today
 

Chuck60

Member
Yes it’s 85w reported on another board.
I checked in system report.

SMC_CLK32_R=32.2khz
I tried checking
PCH_CLK25M_XTALOUT_R= no clock signal
PCH_CLK25M_XTALIN=no clock signal
PCH_CLK32_KRTCX1=no clock signal
 

2informaticos

Administrator
Staff member
Try to start in SMC bypass mode, with charger only.

Did you check if battery is charging?
Do you get voltage on all big coils?
Do you note VCORE droping from 1.1V to 0.85V after few seconds?
 

Chuck60

Member
Nothing smc bypass held power pads for almost 20 seconds and nothing

The coils near heatsink 0v

Only have
12.55 Coil near fuse
5v Near pch
3.3v near usb

PPVCORE_S0_CPU=0
 

2informaticos

Administrator
Staff member
OK, check with battery and charger connected then.
"Do you note VCORE droping from 1.1V to 0.85V after few seconds?"

Also,
"Did you check if battery is charging?"
 

Chuck60

Member
Yes with both battery and MagSafe connected I do see it going from 1.18 to 8.59

It doesn’t appear to be charging
J695”
Pin 1-3 11.22v steady
Pin 4 is 3.42v SMCBUS_SMC_BSA_SCL
Pin 5 is 0v SYS_DETECT_L
Pin 6 is 3.42 SMCBUS_SMC_BSA_SDA
 

2informaticos

Administrator
Staff member
VCORE change looks like board tries to boot.
At least PCH read BIOS and adjust the voltage.

GPU voltages appear too?
Did you change C9560?

BTW, I suppose you meant 0.859 instead of 8.59...
 

Chuck60

Member
Yes I meant .859v
replaced C9560 that was the first thing I changed after tps and isl6259
On L8920 =.985v PPVCORE_GPU_REG_R
 
Last edited:

2informaticos

Administrator
Staff member
Let the board on with battery alone for 15-30 min; then check again if charging.
11.22V is almost full charge.

Did you use hot air to replace C9560?
Is not a good idea at all; heat can affect other things.
 

Chuck60

Member
No I used hot tweezers

Also, I just checked PP3v3_S3 and something just started pulling down my PP3v3_S3 line. I had solid s3/s5 lines I’m sure of it. Now it’s .731v :(
I will get s3 lines up again and let you know if it charges
 
Last edited:

Chuck60

Member
ok so what I’ve found with battery disconnected I have to hold the power pads down for 2-3 seconds and the PP3v3_S3 line comes up to 3.3v with out battery. I don’t have PP5v_S0 When this happens and I mean nothing not even trying to start. Shouldn’t this board power on when a mage safe is connected ?
 
Top