MacBook Pro A1706 820-00239 no power

[mon2]

Re: MacBook Pro A1706 820-00239 no power

Hi. Remove all power -> meter in resistance scale (use the lowest).

Measure the resistance to ground of both pads of where F7000 resides.

Post each measurement with pin #1 / pin #2 reference so we can compare against the same schematic.

BTW - is the multimeter auto-ranging for the resistance or manual adjust?

That is, if your meter reports 'OL' = over limit so next meter scale must be used.

If indeed 0 = dead short but suspecting it is some low resistance reading.

Post your measurement.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Hi. Remove all power -> meter in resistance scale (use the lowest).

Measure the resistance to ground of both pads of where F7000 resides.

Post each measurement with pin #1 / pin #2 reference so we can compare against the same schematic.

BTW - is the multimeter auto-ranging for the resistance or manual adjust?

That is, if your meter reports 'OL' = over limit so next meter scale must be used.

If indeed 0 = dead short but suspecting it is some low resistance reading.

Post your measurement.

Pin #1 to ground around 17-18K oHms Red probe to the ground
Pin #1 to ground around 3M oHms Black probe to the ground

Pin #2 to the ground 000.0 oHms Red probe to the ground
Pin #2 to the ground 000.0 oHms Black probe to the ground

Multimeter auto-ranging for the resistance I am using Zotek ZT102

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

I am not sure but maybe my multimeter is just too cheap to measure low resistance, I am not sure though.

[mon2]

Re: MacBook Pro A1706 820-00239 no power

Your meter should be ok for the measurement.

To clarify, leave the meter on the scale you have posted = ohms scale.

Red probe to pin #1 of the F7000 fuse pad. Black meter probe to ground (metal shield is ok) on the logic board.

Repeat with pin # 2 of the F7000 fuse pad. Black meter probe to ground.

do you still read 0 ohms on pin #2 or is it 'OL' as in the posted picture? 'OL' = over limit.

If you short the meter probes to each other, the resistance should be ~0 ohms. Is that the same reading you are measuring with pin #2 and ground ? That is a hard short circuit if my understanding is correct.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Your meter should be ok for the measurement.

To clarify, leave the meter on the scale you have posted = ohms scale.

Red probe to pin #1 of the F7000 fuse pad. Black meter probe to ground (metal shield is ok) on the logic board.

Repeat with pin # 2 of the F7000 fuse pad. Black meter probe to ground.

do you still read 0 ohms on pin #2 or is it 'OL' as in the posted picture? 'OL' = over limit.

If you short the meter probes to each other, the resistance should be ~0 ohms. Is that the same reading you are measuring with pin #2 and ground ? That is a hard short circuit if my understanding is correct.

Thank you I am sending it now.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Red probe to pin #1 of the F7000 fuse pad. Black meter probe to ground (metal shield is ok) on the logic board.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Repeat with pin # 2 of the F7000 fuse pad. Black meter probe to ground.

do you still read 0 ohms on pin #2 or is it 'OL' as in the posted picture? 'OL' = over limit.

# It changed form OL to 000.0

If you short the meter probes to each other, the resistance should be ~0 ohms. Is that the same reading you are measuring with pin #2 and ground ? That is a hard short circuit if my understanding is correct.

# Yes it is the same reading like I am shorting both probes.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Here are how it looks on my end.

[mon2]

Re: MacBook Pro A1706 820-00239 no power

Yes, agree with your readings of the resistance on the downstream side of (the removed) F7000 fuse.

The macbook logic boards feature a circular adhesive backed dot that is a moisture detector. They will be white, by default, from the factory.

Can you locate these dots on the logic board?

Are any of them red in color? This will mean that the logic board has had exposure to a liquid spill.

PPBUS_G3H travels onto many sites on the logic board. Perhaps the component that is heating up is the CPU / PCH (they are combined in a single package). This component is under a heatsink so can be easily missed if it is indeed heating up.

Remove all power -> Check the resistance to ground of:

PP1V0_SUS
PP1V0_SUSSW
PP1V0_S3
PP1V0_S0SW

Test each of the above anywhere it is convenient on the logic board. A single test measurement for each netname should be ok at this time.

These are expected to be low resistance rails but they should not be @ 0 ohms.

Post each measurement.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Yes, agree with your readings of the resistance on the downstream side of (the removed) F7000 fuse.

The macbook logic boards feature a circular adhesive backed dot that is a moisture detector. They will be white, by default, from the factory.

Can you locate these dots on the logic board?

Are any of them red in color? This will mean that the logic board has had exposure to a liquid spill.

PPBUS_G3H travels onto many sites on the logic board. Perhaps the component that is heating up is the CPU / PCH (they are combined in a single package). This component is under a heatsink so can be easily missed if it is indeed heating up.

Remove all power -> Check the resistance to ground of:

PP1V0_SUS
PP1V0_SUSSW
PP1V0_S3
PP1V0_S0SW

Test each of the above anywhere it is convenient on the logic board. A single test measurement for each netname should be ok at this time.

These are expected to be low resistance rails but they should not be @ 0 ohms.

Post each measurement.

Thank you, I did find the white dots and none of them turned red. I have not attached the F7000 fuse back to the board yet. Below is the result of the components you had me measure for resistance.

PP1V0_SUS = 180.1 oHms
PP1V0_SUSSW = 181.5 oHms
PP1V0_S3 = 328.2 oHms
PP1V0_S0SW = 283.2 oHms

[mon2]

Re: MacBook Pro A1706 820-00239 no power

These are good resistance readings so cpu is likely ok.

Do inspect the parts for any odd looking part that may be damaged.

When you inject 1 volt (not higher), what is the current draw? It should peak to the 2A since it is a dead short.

Can you support higher currents?

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Current can be set from 0-10A Volts 0-30V how far should I set it to when injecting voltage? Also, are we talking about injecting voltage to PPBUS_G3H? Thank you!

PS: It is new year's eve here. Happy new year!!!!

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

I did try to inject voltage 1V 2.4A to ppbus_g3h and found a component that is heating up to the point that I cannot touch too long or it may burn my skin. I did try to find other components cannot find others that is as hot as that component. I am uploading the image now.

[mon2]

Re: MacBook Pro A1706 820-00239 no power

Happy New Year to you and everyone on Badcaps

With some travel luck, hope to visit Manila / Cebu in spring. Often I travel to HK during this time for trade fairs but covid is a major nightmare in that region.

Have been to Cebu before but did not make it to the waterfall excursion planned by the hotel. The malls in Manila / Cebu are many times better than our local ones. Your (veggie) stir fry is amazing!!

1) You do not want to exceed 1 volt - rule of thumb is that stay under the lowest power rail that is on the logic board to be safe. This is to cover the case where the lower voltage rail mosfet may be leaky and can cause damage if you inject a higher voltage.

2) Yes, injecting onto PPBUS_G3H. Red probe onto the SMD pad for F7000, pin # 2. This is the side that is showing 0 ohms to ground on your meter.

Black probe to any good ground.

NO POWER to the logic board - just using this power supply to heat up the shorted part.

3) Proceed to raise the current setting but again, voltage @ 1 volt. When you do this, what does your meter show as the current draw during this event. Expecting that the max current value will be reached since this is a hard short with 0 ohms to ground. Respectively, you are intentionally trying to heat up the shorted component with this process. From my experience, if it is a cap, you will smell it and often will crack / split open under this event. Hoping yours is a similar case. Then remove the cracked capacitor.

Often the shorted caps are tantalum style which just plain die over time and cause a short circuit condition. For our product designs, we just do not use tantalum caps and have widgets that have been operating 24/7 for over 10 year and still ticking.

Curious to know of the current draw as you increase the current setting.

As your logic board consumes more current, the shorted part will definitely heat up. Always keep the voltage @ 1V or under to be safe.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Here is the component I am talking about.

[mon2]

Re: MacBook Pro A1706 820-00239 no power

I did try to inject voltage 1V 2.4A to ppbus_g3h and found a component that is heating up to the point that I cannot touch too long or it may burn my skin.

Ok. That is U9400 and this linked to the nand flash.

Remove all power -> meter in resistance mode.

Measure the resistance to ground @ L9400 which is the switching power supply inductor for this power rail.

What is the reading?

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Ok. That is U9400 and this linked to the nand flash.

Remove all power -> meter in resistance mode.

Measure the resistance to ground @ L9400 which is the switching power supply inductor for this power rail.

What is the reading?

Pin# 1 is 11.49K oHms
Pin# 2 is 11.49K oHms

it keeps on moving till it stop on that value.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

Happy New Year to you and everyone on Badcaps

With some travel luck, hope to visit Manila / Cebu in spring. Often I travel to HK during this time for trade fairs but covid is a major nightmare in that region.

Have been to Cebu before but did not make it to the waterfall excursion planned by the hotel. The malls in Manila / Cebu are many times better than our local ones. Your (veggie) stir fry is amazing!!

1) You do not want to exceed 1 volt - rule of thumb is that stay under the lowest power rail that is on the logic board to be safe. This is to cover the case where the lower voltage rail mosfet may be leaky and can cause damage if you inject a higher voltage.

2) Yes, injecting onto PPBUS_G3H. Red probe onto the SMD pad for F7000, pin # 2. This is the side that is showing 0 ohms to ground on your meter.

Black probe to any good ground.

NO POWER to the logic board - just using this power supply to heat up the shorted part.

3) Proceed to raise the current setting but again, voltage @ 1 volt. When you do this, what does your meter show as the current draw during this event. Expecting that the max current value will be reached since this is a hard short with 0 ohms to ground. Respectively, you are intentionally trying to heat up the shorted component with this process. From my experience, if it is a cap, you will smell it and often will crack / split open under this event. Hoping yours is a similar case. Then remove the cracked capacitor.

Often the shorted caps are tantalum style which just plain die over time and cause a short circuit condition. For our product designs, we just do not use tantalum caps and have widgets that have been operating 24/7 for over 10 year and still ticking.

Curious to know the current draw as you increase the current setting.

As your logic board consumes more current, the shorted part will definitely heat up. Always keep the voltage @ 1V or under to be safe.

Oh, that was a surprise! I have never been to Cebu before but I have seen lots of places to go to due to the pandemic traveling does not really an option now you may end up with lots of road block, here in the PH protocols are being strictly implemented in a few more months everything should be back to normal since we are being asked to report back to work in the office. I do love the veggie fries too XD

I am not sure how I can measure the current draw?? Is it something the multi-meter is capable of?

[mon2]

Re: MacBook Pro A1706 820-00239 no power

So the output side of this regulator does not appear to be shorted.

What is the voltage to ground of the EN pin ?

We want to confirm that the regulator is being enabled.

[Xenoaeuriix]

Re: MacBook Pro A1706 820-00239 no power

3) Proceed to raise the current setting but again, voltage @ 1 volt. When you do this, what does your meter show as the current draw during this event. Expecting that the max current value will be reached since this is a hard short with 0 ohms to ground. Respectively, you are intentionally trying to heat up the shorted component with this process. From my experience, if it is a cap, you will smell it and often will crack / split open under this event. Hoping yours is a similar case. Then remove the cracked capacitor.

You are right I forgot to tell my power supply has lcd display that show the current, it does take the max current the power supply is set to and continually feeding it on that setting heats up the U9400 and I cannot find other components that would heat up or at atleast as hot as U9400.

So the output side of this regulator does not appear to be shorted.

What is the voltage to ground of the EN pin ?

We want to confirm that the regulator is being enabled.

Sorry I do not know what EN pin is...

Sorry my bad, could it be the pin # 15 of the U9400. If so I am trying to test it now.

I am getting 0V on the EN pin#15 of U9400 I will try to solder back the fuse it could be because of that..

Got the fuse re attached, but same ready 0V on U9400 Pin# 15

I got 0.040V on the EN pin.