820-00875-01 Spill no screen

Hi, I know this might have been asked before, tried to look for a specific answers but couldn't find anything more than this:


I am looking for 0402 smd parts for my 820-00875-01 ( A1708 ). I already purchased a set of standard caps off local ebay ( allegro ) in Poland ( where I am from ).
But I need to get my hands on 0402 63.4K resistor. I can't find it anywhere in local retail and I am considering ordering from China. The shipping is about 1 - 2 mths so therefor I have some questions:

- can I order a set ( book ) so that I don't have to wait another time one I find another part that needs to be replaced
problem with that approach is the values of resistors in the book doesn't really match exactly the value I need, for example I need mentioned above 63.4K and they have 62K in the list of book components. They do have single value offers with exact resistance but then I need to still figure out a list of which it would be smart to order since the delivery time etc. They are of course dirt cheap but the delivery time makes for the whole discussion.

- I know in the youtube vids Louis always grabs parts from donor boards and that it is preferred solution in this forum - I don't have that option. I don't run a shop, I am a noob and I just want to fix my board if I can.

- both above lead to my other question: how strict does the value of resistor have to be ? I did some calculation and it seemed to me that there is no difference between 63.4K and 61.9K res on 12V over 1/16W for example, therefore is it possible to consider different parts for the job ? I know it depends so I will bring specific example of R8402 in my board, which is the res in question.

- how do I approach a list of components to order ahead ? My board is without that resistor currently.

Backstory to whole repair:
Mac had a spill. Local certified service wanted more money for repair than it costed new. Local non certified service still wanted a lot of money ( enough to buy parts, tools etc and still have fun repairing it and learning something ).

Screen is black, keyboard doesn't show caps-lock light but it seems to be responding to SMC reset.
Fan is spinning.

Board outside of case and disconnected battery, screen etc. takes 20v, at first seconds ~550mA then ~300 mA

Damaged area is around Q8400, the C8401 was missing ( looked like it was there before looking at solder and slots ) so I added it. I blew away the R8402 with hot air and it's MIA.

There is 12v at C8401 2nd pin ( LCDBKLT_EN_L ). There is proper resistance on Q8400 between 3 & 4 pins.

--- As mentioned above I am a noob. My knowledge of the subject comes form your youtube channel. If you have any tips on what is smart to do / diagnose at this stage pls let me know and I can measure things.

Thanks for everything.


Staff member
First of all, welcome to the forum!

5% tollerance is good enough.
Even 10% shouldn't be a problem.
Get resistors book, without caps.
Mixed resistors + caps books are bulshits.
Just try to get as many resistance values possible in the same book.

R8402 value is not critical.
There will work 47K, as even 20K, or 75K.

Try to understand the function of a component in the schematic.
Then is easy to find a replacement.

If Caps Lock light doesn't react, there should be something more than backlight problem.
Liquid spill on backlight area is very dangerous, as can cause leakage from high voltage to a data line connected to CPU.

Post PPVCCCPU_S0G in the first seconds and also when power consumption drops to 300mA.
Ok, actually things got a bit better since I last had it put together.

CapsLock reacts, there is a charging sound as well.
0.008 so I think it's not there? Keep in mind I still have not soldered the R8402 so it's missing from the board. I also might have damaged the pad from under R8402 ( pin 2 ) - is it enough to run a wire from the probe which is just near it ?
>Be sure to make good contact with pin 11/U8400.

How do I check that ? There seem to be no probe points for this pin and it's under the chip.
true, I am able to get to that pin with some tool improv. What worries me is that the broken pad seems to be going trough the board on to the other side, is that correct ? Seems like almost impossible to solder to whatever is left in there
C8442 is actually missing from the board, I can see it in the schematics but not on the board. Looks like an important component