Burnt resistor (R1802) Logicboard A1702

[Phail99]

Dear community!

I have a problem with my MB Pro 2017. After switching on, everything works normally in principle. But after a certain time the MB freezes completely and then it crashes. As an error message I get kernelpanics displayed (see pictures). I have now taken out the logicboard to check it for abnormalities. In fact I noticed a burned out resistor. This resistor is called R1802 and according to my research it is connected to the CPU. Do you think this resistor is causing the problems/kernel panics?

Many thanks in advance!

Greetings

Phillip

Logicboard number: 820-00840-a

(Sorry that some of the bug reports are not fully visible, but I wanted to quickly photograph it before the MB crashes again)

 

[Phail99]

C1804 {1} XDP_CPU_PWRBTN_L is 0.660 in diode mode

J1800 {42} XDP_CPU_PWRBTN_L is 0.660 in diode mode

R1802 {2} XDP_CPU_PWRBTN_L (not replaced, I am waiting for the spare part) is 0.662 in diode mode

R1450 {2} PM_PWRBTN_L is 0.660 in diode mode

R1450 {1} PP3_V3_S5 is 0.352 in diode mode

If I replace R1802, is it possible that the problem will no longer occur? Or do you think it has some deeper reason?

 

[Sanpete]

Hope you're posting this at iFixit too. Seems more their kind of thing, though maybe too advanced for them too. Maybe Rossman Group. Good luck.

 

[herb2k]

C1804 {1} XDP_CPU_PWRBTN_L is 0.660 in diode mode

J1800 {42} XDP_CPU_PWRBTN_L is 0.660 in diode mode

R1802 {2} XDP_CPU_PWRBTN_L (not replaced, I am waiting for the spare part) is 0.662 in diode mode

R1450 {2} PM_PWRBTN_L is 0.660 in diode mode

R1450 {1} PP3_V3_S5 is 0.352 in diode mode

If I replace R1802, is it possible that the problem will no longer occur? Or do you think it has some deeper reason?

Did you try to desolder one pad of the resistor (take it out of circuit) and check it in resistance mode? Resistors usually blow "open" and not "short".

Diodes should normally read in one direction at ~0.5 to 0.6V and the other direction as open circuit (when removed from circuit).... but when you have components in parallel the readings are often skewed.

 

[Phail99]

Did you try to desolder one pad of the resistor (take it out of circuit) and check it in resistance mode? Resistors usually blow "open" and not "short".

Diodes should normally read in one direction at ~0.5 to 0.6V and the other direction as open circuit (when removed from circuit).... but when you have components in parallel the readings are often skewed.

Hi @herb2k, please excuse me for getting back to you so late, but unfortunately I didn't get a notification that you had responded to my question! In the meantime I have successfully replaced the resistor... Unfortunately the problem is unchanged... The macbook starts - after a short time it freezes, gets kernel panics and crashes.

Could you please explain your suggestion again in more detail? If necessary I will desolder the resistor again, I have nothing to lose.

 

[herb2k]

Hi @herb2k, please excuse me for getting back to you so late, but unfortunately I didn't get a notification that you had responded to my question! In the meantime I have successfully replaced the resistor... Unfortunately the problem is unchanged... The macbook starts - after a short time it freezes, gets kernel panics and crashes.

Could you please explain your suggestion again in more detail? If necessary I will desolder the resistor again, I have nothing to lose.

Since you've replaced the resistor, I think that is not your problem.

With measuring components in diode mode, you have to remember you're measuring everything in parallel to that component.

Sometimes it's necessary to un-solder capacitors and diodes and test them "out of circuit" so they are isolated and then you can individually confirm whether or not the part is bad.

Note, I'm not a professional repairer, just sharing some of my own experiences.

Check out badcaps forums or rossman group's forums - they have more lively discussions on these types of problems than macrumours.

Good luck!

 

[Phail99]

Since you've replaced the resistor, I think that is not your problem.

With measuring components in diode mode, you have to remember you're measuring everything in parallel to that component.

Sometimes it's necessary to un-solder capacitors and diodes and test them "out of circuit" so they are isolated and then you can individually confirm whether or not the part is bad.

Note, I'm not a professional repairer, just sharing some of my own experiences.

Check out badcaps forums or rossman group's forums - they have more lively discussions on these types of problems than macrumours.

Good luck!

Thank you very much for your answer now I understand what you mean.
I am also far from a professional repairer... but I am still grateful for any advice. And yes, I will check out badcaps!