MacBook Air A1370 charging issue

[mon2]

Re: MacBook Air A1370 charging issue

With meter in voltage mode, place red meter probe on c7050 on one side. Black meter probe to ground.

What is voltage when the battery is connected?

Then repeat with red meter probe on other side of c7050.

Expecting to see the same voltage as on the series resistors on these traces.

Can you post pics of the logic board for this area?

[74kieran]

Re: MacBook Air A1370 charging issue

Hi,

0v each side. And attached a image

Thanks

[74kieran]

Re: MacBook Air A1370 charging issue

I will re check my PP3V42_G3H_REG voltage

[mon2]

Re: MacBook Air A1370 charging issue

Based on the post # 22 (0 volts on both sides of C7050) - it appears that you have broken traces.

See attached.

Remove all power. Meter in lowest resistance mode scale.

Check the resistance between pads # 1 and #2. It should be about 0 ohms since this is a direct PCB trace (unless the trace is damaged).

Confirm it.

Then check the resistance between pad # 1 and # 3 (at the IC). Again, as a direct PCB trace, the resistance should be ~0 ohms.

Confirm it.

Then repeat for the other side of the cap @ C7050.

If you see other resistance values, the PCB traces are damaged and can be repaired easily but first need to see these readings.

Also, do test the resistance between pad # 2 & # 3 for the top of C7050.

Then again for pad # 2 & # 3 for the bottom of C7050.

This is to confirm which trace(s) are damaged.

Update - from the posted pic - is there a solder short on the IC ??

Apply flux on these IC pads -> hot air till the pads are no longer looking like they are shorted. Use low air pressure but high heat to allow the solder to melt and wick up under the IC.

The pads look like they are shorting.

[74kieran]

Re: MacBook Air A1370 charging issue

I agree it does look like there is a solder short. Going to order a better microscope now which hopefully comes tomorrow so can double check. It seems i get 0.03ohms on R7051 and 0.01ohms on R7052.

When it comes tomorrow I will double check and update the thread.

Thanks for your help

[74kieran]

Re: MacBook Air A1370 charging issue

I don’t think they are touching. I have included a photo. It’s strange as I had no continuity before plugging it in. Soon as I plug a charger in and unplug it. There is no continuity. I’m get 0.03-0.04 ohms. Would this be a faulty IC chip do you recon?

[74kieran]

Re: MacBook Air A1370 charging issue

Image

[mon2]

Re: MacBook Air A1370 charging issue

Can you provide detail on how you are measuring this area of the circuit?

Follow the schematic for a point of reference and post the measurements for each leg of the parts with their resistance values.

The IC may be faulty but we should first check each measurement.

[74kieran]

Re: MacBook Air A1370 charging issue

Hi,

Sorry it has been a while. I have done some further testing. Here are all of my finding so far

U7000 Pin 18 to R7051 pin 1 is 0hms Voltage of R7051 pin 1 is 0.16v
U7000 Pin 17 to R7052 pin 1 is 0hms Voltage of R7052 pin 1 is 0.16v

C7050 Pin 1 is 0.17v (This does move around 0.13v-0.18v)
C7050 Pin 2 is 0.17v (This does move around 0.13v-0.18v)

U7000 Pin 18 is 0.18v
U7000 Pin 17 is 0.18v

The schematic you shown for U7000 is for a different board. Is there a way of testing the voltage going into the IC Chip.

Thanks

[74kieran]

Re: MacBook Air A1370 charging issue

Currently looking at U9480 as there is no voltage on any pin. I am currently following schematics backwards to see where the 3.3v stops

[74kieran]

Re: MacBook Air A1370 charging issue

Is there any common issue to this sort of issue?

[74kieran]

Re: MacBook Air A1370 charging issue

I have found the the green light only works when laptop is on. But the laptop still decharges. I have also found if the laptop is used without battery then it will shutdown randomly(Anywhere up to 1 minute). I have also found that L7630 is getting hot