Search results

I also just noticed that the board does not start up when no battery is connected - I believe that's wrong for this model. Without the battery, the USB-C meter reads 20V but only 0.07A and no startup.

I replaced U7000, R7060, and Q7065 and the situation is unchanged.

Both are around 3Ω.

Can anyone help, please?

Where do I look next? Charging chip? Battery current?

Hmm, I've tried two batteries and I see the same discharging behavior for both.

I measured several rails from page 66 and some others. Does this look as it should? Not energized: PP1V1_S3: 0 PP0V6_S3: 0 PP1V8_S3: 0 PPVCC_S0_CPU: 0 PP1V8_S0SW_CPU: 0 PM_SLP_SUS_L: 0 PM_SLP_S3_L: 0 Energized: PPBUS_G3H: 11.8 PP5V_G3S: 5.1 PP3V3_G3H: 3.3 PP3V3_S5: 2.0 PP1V8_G3S: 1.8...

This A2179 Air arrived dead after customer dropped it. One of its USB-C ports showed 20V, the other 5V. I replaced both CD3217s from an identical donor board and the machine appeared to work fine. However, when the computer is shut down, the battery continues draining (about 10-15% in 6 hours)...

I ended up checking all lines in the USB-C area that run between front and bottom logic board. I found 8 broken or intermittent lines, so this board surely has plenty of internal damage. I'm saying good-bye to it.

Yes, I agree. But which ones do I check? I measured the CC lines and the I2C_UPC bus lines for all possible combinations of CD3215s and USB-C plugs. See attached.

I checked the lines between XA and XB (I2C_UPC_X) and they are all good. I did find two missing connections between XA and the redriver U3000 (I2C_UPC_X_DBG_CTL), but those should not matter for the inter-CD3215 communication, right?

Yes, cycling PPBUS 12.6V for 15-20s, then 12.3 for 2s. Checked NAND seating and solders and all are ok. Of course, there's no guarantee that the NANDs were fully functional on the donor board...

Yes, of course.

From a donor board.

Replacing all 5 NANDs removed the shorts on P1V8_SSD0 and P2V5_NAND_SSD0 and I now measure all correct voltages. But the machine is stuck at 20V 0.04A with no startup. No shorts on the big coils. DFU Restore fails with error 9. PPBUS is cycling back and forth between 12.6V and 12.3V. With...

Yeah, thanks for confirming my suspicions. The CPU does get unusually hot within seconds.

I get one brief flash on my USB mouse, then nothing. No external video. No Caps Lock light. PPVCC_S0_CPU is initially 0.97V, then stabilizing at 0.87V.

This MacBook originally showed a short on PPBUS, which I traced to one of the CPU power drivers (U7410). Replacing it removed the short. Now the trackpad clicks and the fans are spinning, but it doesn't start up. PPBUS is 12.57V and the USB-C meter reads 20V and 2-3A (without a battery...

If a trace is broken it must be inside the board. I could remove the two troublemaker CD3215s and check for continuity of the connections between XA and XB. Any pointers as to which lines are the important ones? I2C_UPC_XA_DBG_CTL? I2C_UPC_X?

After replacing all four CD3215s, the situation is unchanged. One additional observation is that the bus connecting the CD3215s together (I2C_UPC_) shows values around 2V on half of the CD3215s, and 3.3V on the others. Help!