macbook pro 2012 820-3115-b identifying missing components

[carlosfandango26]

hi guys hope im in the right place for this topic... recently bought a used macbook pro 2012 and after doing a thermal repaste the power button will not work. however if i disconnect the battery it will power up from the charger and appears to work fine... ive searched on the board and i have found what appears to be 2 missing components R5710 and c5710
must have snagged them when i was struggling with the keyboard ribbon.
can anyone tell me what these are ie: capacitors, resistors and where i can get them from and how the hell to solder these flea size components back.. lol

thanks.

[mon2]

Re: macbook pro 2012 820-3115-b identifying missing components

If the part starts with an 'R' = resistor.

If the part starts with a 'C' = capacitor.

The parts are 0402 SMD size parts and will require tweezers to place them on the board.

Not impossible to solder by hand with a normal soldering iron but will require a fine tip.

Do you have a fine tip soldering iron ? Using the tweezers + solder (standard leaded solder is fine) - the part can be held down and soldered.

The resistor & capacitor do not have a polarity.

You are in the UK and you will be fine to locate the parts online or locally if in a rush. Aliexpress (China) will have the best price but will take a few weeks for the delivery.

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

all my questions answered in a flash.. thankyou kind sir. i will report back once ive sorced the items.. need to brush up on my soldering skills too... lol

do you concur with my findings and think that this is my problem..?

thanks

[mon2]

Re: macbook pro 2012 820-3115-b identifying missing components

Yes, it is very likely the root of the problem.

See attached.

Apple / Foxconn likes to use surface mount pads where you can use tweezers to short the pad to ground to mimic the ON / OFF switch.

Locate the pads and attempt to use these alternate ON / OFF switch pads to confirm the logic board is able to turn ON / OFF.

You should be able to find one pair of the pads on one side of the PCB and the other pair on the opposide side of the board. That is, top side vs. bottom side for convenience of the tech who may be servicing the board.

Respectively, the keyboard is then not required to turn the board ON / OFF.

PS: If you are not comfortable with the soldering, consider to locate a friendly cell phone repair shop and ask them ' can you solder 2 parts that are 0402 in size on a logic board ? '.

Cannot see this being an expensive service for a repair shop.

Otherwise, if you can, find some flux which helps but not really required for these 2 parts - just makes the solder flow a bit better.

Watch some videos on the microsoldering process to gain some confidence but it is a great learning process. Buy some spares of both parts as they are easy to lose being so tiny in size.

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

thankyou very much you've been very helpful..


hi .. when i search for the parts do i just look for a 1k ohms resistor size 0402 or the part number R5710 . ?
and likewise for the capacitor..?

thanks

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

would these be any good..? the capacitor is rated as 16v rather than 10v.. not sure if that matters..?

[mon2]

Re: macbook pro 2012 820-3115-b identifying missing components

Both parts are fine.

The 10v means that the part they have soldered can support upto 10v peak for a normal operation.

Your choice can support 16v peak without damage.

There is a minor argument on the capacitance value that changes with the voltage rating but this is a no-care for this portion of the design.

The resistor is also ok.

The reference of the parts are the 'R' and 'C' values - they are used to locate where on the circuit board the physical part resides.

For example, the first part in a design maybe C1 = first capacitor; C2 = 2nd capacitor and so on.

R1 = first resistor; R2 = 2nd resistor, etc.

The part costs are very fair considering they may be local to you and should arrive quickly.

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

Both parts are fine.

The 10v means that the part they have soldered can support upto 10v peak for a normal operation.

Your choice can support 16v peak without damage.

There is a minor argument on the capacitance value that changes with the voltage rating but this is a no-care for this portion of the design.

The resistor is also ok.

The reference of the parts are the 'R' and 'C' values - they are used to locate where on the circuit board the physical part resides.

For example, the first part in a design maybe C1 = first capacitor; C2 = 2nd capacitor and so on.

R1 = first resistor; R2 = 2nd resistor, etc.

The part costs are very fair considering they may be local to you and should arrive quickly.

Thanks for clearing that up for me... Still learning something everyday and im in my 50s now... lol
Knowledge is power my friend ...
Thankyou..

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

ok quick update.. i found the r5710 in the bottom of the macbook chassis.. no sign of the c5710. Anyways i proceeded with the soldering iron and now i have what seems to be a fully functioning macbook... not sure if the missing c5710 is going to cause me any problems later down the line though.. fingers crossed.
tool used: a crappy old soldering iron, the wifes eyebrow tweezers lol and a magnifying glass ... fiddly is an understatement..

[mon2]

Re: macbook pro 2012 820-3115-b identifying missing components

The combination of of the resistor & capacitor is creating an RC circuit. R for resistor, C for capacitor. In summary, it creates a poor man's delay circuit.

It is effectively for removing the mechanical bounce from the keypress.

When you press 2 contacts, in the digital world, there is all kinds of ringing of the voltage from ON/OFF of the contacts mating. Rarely is it a solid ON or solid off. This ringing can cause the downstream device to pulse ON / OFF along with the bounce. (Jay Z - bounce with me ??)

For now it may be ok but do install the cap when it arrives to properly settle this repair.

wifes eyebrow tweezers

LOL - we used the same here years ago when starting with PCB repairs but did not have the good stuff. One of the girls brought it in. They were clumsy as heck to use due to lack of precision.

[carlosfandango26]

Re: macbook pro 2012 820-3115-b identifying missing components

ok... the capacitors are on order so i will finish the repair later..
actually the wife is happy now because i took the tweezers to the grinding wheel to sort out the precision problem... thought i was gunna be in the dog house.. lol
anyhow.. thanks for all your help mon2 ,,, your a legend