820-00165 "No Camera detected"

[ligym60]

Hi I have a 2- 820-00165 with the same issue No camera detected

History: Both had water damage around SMC. both when i got them had no green light. repaired a few blown resistors and traces. everything works
except
Camera
"No Camera Detected"

1) I inspected the connector pins J4002 for continuity to inside pins i also checked for pin clearance. Replace the entire cable and camera/ALS cable including new camera module. Still the same issue. Checked all the filters going to j4002 and voltages.

2) I cleaned ME region Twice with no change.

3)I replaced u3900"BCM15700A2KFEB4G" the one good thing is that now the ALS circuit is working. So by covering the eye of the sensor the keyboard is illuminating

My next step is to set up my Oscilloscope
I have tested these lines Below and as of last the CLK/DATA was all over the place.
The issue can be my O'scope is only 100mhz these lines might be out of range since it says mipi is .7-2ghz as for the I2C/smbus I will try using Serial Bus Decoder on the scope to see if i see any data/clock.
I'm going to test J4002 for all these signals To see if anythings changed. if anyone has experienced this issue Please throw me a bone

MIPI_CLK_CONN_N
MIPI_CLK_CONN_P
MIPI_DATA_CONN_N
MIPI_DATA_CONN_P
SMBUS_SMC_1_S0_SDA
SMBUS_SMC_1_S0_SCL
I2C_CAM_SCK
I2C_CAM_SDA
PP5V_S3RS0_ALSCAM_F

[piernov]

Re: 820-00165 "No Camera detected"

You should try under Linux, the driver puts out pretty verbose kernel debug message and it could help narrowing down the problem.

[ligym60]

Re: 820-00165 "No Camera detected"

Thank you will give it a go under linux

[ligym60]

Re: 820-00165 "No Camera detected"

Hey @piernov I didnt see any errors in verbose. I tried $lspci and $lsmod to see if i can find the camera listed but I found none.

[piernov]

Re: 820-00165 "No Camera detected"

Under `lspci` a "Multimedia controller" with "Broadcom" in the name should show up (not the "Network controller" which is the WiFi card), it's the camera controller IC U3900 and it's connected to the PCH through a PCIe bus. The camera itself is connected to U3900 through a MIPI bus.

Under Linux you have to install this driver manually: https://github.com/patjak/bcwc_pcie
But if you don't even have the Broadcom Multimedia controller under lspci then installing this driver is pointless (it won't trigger so no message will be shown).
Are you sure U3900 is soldered properly? Do a thorough visual inspection near it to make sure there's no missing caps/resistors.


I still attach a picture of what the kernel log looks like when loading the facetimehd driver.

[ligym60]

Re: 820-00165 "No Camera detected"

No, I didn't see the multi media controller " Broadcom" only network controller with lspci it didn't show
I inspected u3900 under a microscope again but its very tight with the board. These chips I bought from a china I ordered 3 of them. I have 2 boards with the same exact issue and both had water damage around SMC chip. Before I replace u3900 i'd like to trace from PCH to u3900 and from u3900 to camera. Since I've already done this with DMM. Do you think Probing signals with O'scope would help? Thank you @piernov for your help

[zpi]

Re: 820-00165 "No Camera detected"

Hello guys, when i have this problem and all voltages for u3900 input is present %90 changing u3900 solves problem (offcourse first cheking main voltages and coils.

[piernov]

Re: 820-00165 "No Camera detected"

Yes indeed but U3900 was already replaced here.
But as you said power rails on U3900 should be checked as well. It uses a 3.3V input and generates a bunch of other power rails.

[ligym60]

Re: 820-00165 "No Camera detected"

hello everyone I'm sorry for the slow response I've been working on other things:
I retested these signals today

PP0V675_MEM_CAM_VREFCA=.675V
PP0V675_CAM_VREF=.0V
PP1V8_CAM= 1.79V
PP1V2_CAM= 1.2V
PP1V35_CAM=1,34V
PP3V3_S3RS_CAMERA=3.3V
CAM_SENSOR_WAKE_L=0V
CAM_PWR_SEL=.5V
CAMERA_PWR_EN=3.3V
CAM_TEST_OUT=0V
PCIE_WAKE_L=3.3V
SYSCLK_CLK25M_CAMERA=25M

Test with oscilloscope
i wasn't able to get the air on screen to activate camera on osx i think my thunderbolt adapter is acting up :/
Thank you for your help and continued support

[ligym60]

Re: 820-00165 "No Camera detected"

@piernov Hi I rechecked the power rails and it seems that all are up and running. I still question the clk as it is unstable sometimes reading good other times not. I have a few u1900 chips i was thinking of replacing it before trying another u3900. I figured I'd ask before sacrificing another chip. Have i missed something? any other thoughts before i proceed?
Thank you

[ligym60]

Re: 820-00165 "No Camera detected"

It's Fixed resolved clk issue. reflow and its done.

[kjchatman]

Re: 820-00165 "No Camera detected"

what was reflowed?

[tlough75]

Re: 820-00165 "No Camera detected"

What temps did you use? I have an 820-00165 with a shorted U3900, would like to try to change just for fun. I already sold the customer a replacement board with working U3900 so they gave me the old one.