students_t
Member
OK, I've swapped in the U7800 from my scrap board, and now the voltage for 3V0_G3H is up to 2.77 V. Still not 3 yet though. What do you think?
-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
A1706 no power
- Thread starter students_t
- Start date
In such case, the problem may be PCH.
What about the other U7800's LDOs now?
Do you get 3V3_S5?
What about the other U7800's LDOs now?
Do you get 3V3_S5?
students_t
Member
PP3V3_S5 at C7840 shows 3.36 V
C7833 (LDO3V, PP3V_PMICLDO) shows 0 V
C7836 (LDO5V, PP5V_PMICLDO) shows 0 V
C7837 (VINLDO3, PPBUS_PMIC) shows 13.11 V
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0 V
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0 V
C7833 (LDO3V, PP3V_PMICLDO) shows 0 V
C7836 (LDO5V, PP5V_PMICLDO) shows 0 V
C7837 (VINLDO3, PPBUS_PMIC) shows 13.11 V
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0 V
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0 V
Check diode mode to ground on missing LDO lines.
You may have bad solders on U7800; or bad PCH...
You may have bad solders on U7800; or bad PCH...
students_t
Member
I could certainly believe there being bad solders. I diode mode I get:
C7833 (LDO3V, PP3V_PMICLDO) shows 0 V and beeps
C7836 (LDO5V, PP5V_PMICLDO) shows 0 V and beeps
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0 V and beeps
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0 V and beeps
C7833 (LDO3V, PP3V_PMICLDO) shows 0 V and beeps
C7836 (LDO5V, PP5V_PMICLDO) shows 0 V and beeps
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0 V and beeps
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0 V and beeps
Don't write "V" after diode mode readings.
That voltage is generated by your multimeter.
Avoid any confusion with real voltage readings; when charger, or battery is connected.
Beep doesn't mean always short.
Post exact resistance (ohm scale) to ground.
That voltage is generated by your multimeter.
Avoid any confusion with real voltage readings; when charger, or battery is connected.
Beep doesn't mean always short.
Post exact resistance (ohm scale) to ground.
students_t
Member
C7833 (LDO3V, PP3V_PMICLDO) shows 0.9 Ω
C7836 (LDO5V, PP5V_PMICLDO) shows 0.9 Ω
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0.8 Ω
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0.9 Ω
C7836 (LDO5V, PP5V_PMICLDO) shows 0.9 Ω
C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) shows 0.8 Ω
C7830 (VDDIO0, PP3V3_PMICLDO) shows 0.9 Ω
I bet for bad U7800, or shorted solder balls underneath.
students_t
Member
I tried removing and re-cleaning the contacts and then reattaching U7800. I now get the following readings:
Maybe an improvement, but still with some shorted solder balls under U7800?
| Location | Diode mode reading | V |
|---|---|---|
| C7880 (PP3V0_G3H) | 0.400 | 2.75 |
| C7840 (PP3V3_S5) | 0.322 | 3.36 |
| C7833 (LDO3V, PP3V_PMICLDO) | 0.380 | 3.31 |
| C7836 (LDO5V, PP5V_PMICLDO) | 0.001 beeps | 0 V |
| C7837 (VINLDO3, PPBUS_PMIC) | 0.368 | 13.11 V |
| C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) | 0.000 beeps | 0 V |
| C7830 (VDDIO0, PP3V3_PMICLDO) | 0.375 | 3.31 |
Maybe an improvement, but still with some shorted solder balls under U7800?
Did you check diode mode on these caps before resoldering U7800?
students_t
Member
I only checked diode mode before resoldering on the ones that I mentioned on Saturday (sorry about the "V" here, just leaving it as quoted)—
You didn't mention exact values to ground there.
Not always beep is short.
If you remove U7800, clean the pads and check diode mode on all LDOs.
You shouldn't get any short, or low reading.
Not always beep is short.
If you remove U7800, clean the pads and check diode mode on all LDOs.
You shouldn't get any short, or low reading.
students_t
Member
OK, with U7800 removed:
| Location | Diode mode reading | Ω |
|---|---|---|
| C7880 (PP3V0_G3H) | 0.436 | 1– (no reading) |
| C7840 (PP3V3_S5) | 0.321 | 1– (no reading) |
| C7833 (LDO3V, PP3V_PMICLDO) | 1. (no reading) | 1– (no reading) |
| C7836 (LDO5V, PP5V_PMICLDO) | 0, beep | 1.0 |
| C7837 (VINLDO3, PPBUS_PMIC) | 0.419 | 1– (no reading) |
| C7831 (VDD5_VPROGOTP, PP5V_PMICLDO) | 0, beep | 1.1 |
| C7830 (VDDIO0, PP3V3_PMICLDO) | 1. (no reading) | 1– (no reading) |
So you have short at 5V_PMICLDO; no need to check the same line on two capacitors.
Once U7800 is removed, there only remains few capacitors to check: C7631/5/6, C8016/25.
Remove them one by one and see when the short to ground disappears.
Inspect their solders first; maybe you just moved them.
Once U7800 is removed, there only remains few capacitors to check: C7631/5/6, C8016/25.
Remove them one by one and see when the short to ground disappears.
Inspect their solders first; maybe you just moved them.
students_t
Member
I ran into some problems cleaning up the pads where U7800 goes; I will try fixing this (I've been a little busy lately), but I have an alternative that I want to ask you about. I joined this forum because I wanted to learn about electronics repair with practical experience (already a success), and I considered it a bonus if I could recover the data on the drive of my dead macbook. Time permitting, I will try to continue with the original plan as well, but I want to know about the difficulty of swapping the SSD on A1706 boards.
I got another cheap and working A1706 macbook with seemingly the same specs as the one I've been working on with your guidance. I see that the SSD is soldered to the board, but when I looked at videos I see that the contacts are larger and spaced farther apart (i.e., it looks perhaps easier to change out than U7800 (in terms of soldering skill)). Assuming I did the removal and re-soldering correctly, would swapping the SSD from the dead board onto the working board work? Or are there problems with doing this?
I got another cheap and working A1706 macbook with seemingly the same specs as the one I've been working on with your guidance. I see that the SSD is soldered to the board, but when I looked at videos I see that the contacts are larger and spaced farther apart (i.e., it looks perhaps easier to change out than U7800 (in terms of soldering skill)). Assuming I did the removal and re-soldering correctly, would swapping the SSD from the dead board onto the working board work? Or are there problems with doing this?
Which SSD do you want to recover?
students_t
Member
The main 512 GB drive.
A1706, or A1708???
students_t
Member
Sorry, I must have had a typo or be misunderstanding something. I currently have three A1706 boards—one is a scrap board, one is a board from my old laptop, and one is a board from a laptop I just purchased. I want to remove the 512 GB SSD from my old laptop board and use it to replace the 512 GB SSD on my "new" used laptop board. So then all of the files saved on the old laptop will be recovered.
students_t
Member
Ok, I think I follow what you are getting at. The A1706 has two hard drive SSDs I guess (as shown in pic)? So I would need to be changing both?
Edit: basically, this video (
) talks about T1 and T2 macbooks. In the case of T1 macbooks they don't explicitly say if the "direct transplant" method will work (instead they talk about doing a modification to allow for removable SSD). For the T2 MacBooks they talk about how the setup there has 4 NANDs that have critical stuff spread across them such that if one fails everything stops working, and you have to replace them in sets.
So I envision that I would be taking the two NANDs from my old laptop board and transplanting them onto the working board. But I want to make sure that there isn't some catch that will make this not work. Like, if for some reason I have to wipe and reinstall everything as part of the process of doing the transplant (as video suggests is case for T2 NAND transplants) then obviously that defeats the purpose. Do you know of any such issues, or do you think that a simple transplant will work?
Edit: basically, this video (
So I envision that I would be taking the two NANDs from my old laptop board and transplanting them onto the working board. But I want to make sure that there isn't some catch that will make this not work. Like, if for some reason I have to wipe and reinstall everything as part of the process of doing the transplant (as video suggests is case for T2 NAND transplants) then obviously that defeats the purpose. Do you know of any such issues, or do you think that a simple transplant will work?
Attachments
Last edited: