Hello everyone, I've searched the forum but couldn't find a case with the exact same symptoms, so I'd appreciate some advice.
I'm working on a macbook pro late 2020 with the board 820-1949. The laptop came in with visible liquid damage and corrosion in various areas:
-speaker amp right side (C6483, C6455) - no shorts detected
-keyboard backlight area (pin 2 of J8401 was destroyed plus some minor corrosion)
-C2070 corroded under the pads
-The most afflicted area is around UB260, RB296, RB29A, RB291, RB263, U3100_R (just a bit on the right side), all the area...
speggio91
Senior Member
Last Activity: 03-31-2025, 05:15 PM
Joined: 04-11-2020
Location: Italy
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Macbook Pro A2251 820-1949 5V cycling
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Hi everyone,
I wanted to follow up and share the good news. I successfully repaired it! Hopefully, this post will help others who might face the same issue.
After reaching out to Focusrite technical support, I was amazed by their pro-repair approach. They provided me with the correct U1 replacement free of charge and even shared the values of the destroyed capacitors so I could replace them properly.
Here are the details of the replaced components:
-U1 (VBUS voltage regulator) – Replaced with STEP DOWN CONVERTER SYNCHRONOUS 1A MP2141NGTF ADJUSTABLE... -
Focusrite Scarlett Solo 3rd Gen component identification
Hi everyone,
I'm trying to repair a Focusrite Scarlett Solo 3rd Gen audio interface that was accidentally exposed to 12V on the USB-C VBUS line instead of the normal 5V. A component marked as U1 on the PCB has completely blown up together with the capacitors C17, C15.
From the teardown video linked below, it's indicated that U1 is a voltage regulator (switcher) with 6 pins. Unfortunately, the original part on my board is so damaged that I can't make out any markings or identify it.
Video Link: [URL]https://youtu.be/8onqBc5iTB4?si=KHtU772wsproFGZy&t=633[/URL]... -
Thanks everyone for the suggestions so far!
I've done some more troubleshooting since my last post. I replaced all three optocouplers, and I've also tested all the diodes, zener diodes, transistors, and resistors on the primary side. None of them seem to be faulty. I haven't tested any of the capacitors yet, so that's still an area to explore.
At the moment, I'm focusing more on the secondary side, where there's a DAS01B chip that I suspect might be a control chip communicating with the optocouplers, but unfortunately, there's no datasheet available for it. I've already...Leave a comment:
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I have an update: I found that a 30Ohm resistor that connects the TEA2016AAT to GND was broken, so I replaced it and now the power supply will output the 12V without shutting down.
The problem now is that it fails under load. Even at lower currents the voltage drops drastically, e.g. at 4A it drops to 10.9V. The voltage on the filter capacitors remains stable at around 395V, but sometimes it goes up to 410V, especially when I disconnect the load.
Do you think the problem is on the secondary side? Because I think the PWM and APFC are working fine.Leave a comment:
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Thanks for the suggestion!
I desoldered and measured the ESR of both main filter capacitors, as well as all the 12V output electrolytic capacitors. Every capacitor tested fine with 0 ohms ESR, and the capacitance values are within the expected range.
Since the capacitors seem to be in good condition, I'm thinking the issue might lie somewhere around the PWM/APFC/LCC controller (TEA2016AAT). I'm considering checking the resistors and diodes in that area, but if you have any specific pointers or suggestions on which components to focus on, I'd really appreciate the guidance....Leave a comment:
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PS5 PSU ADP-400DR no power
Hi everyone,
I'm working on a PS5 power supply (model ADP-400DR) that's giving me some trouble. The issue is that no 12V output is coming out.
Initially, I found the DAP053T chip responsible for APFC/LCC/PWM was faulty because it was getting very hot (around 100°C) and had no VCC on pin 13.
I replaced it with an equivalent chip (TEA2016AAT). Now, when I connect the main AC voltage, I measure 395-400V on the main filter capacitor, but the 12V output appears only for a few seconds before it starts dropping to zero.
I then disconnected pin 3 of the optoisolator... -
FINAL UPDATE ON MY CASE:
replacing the IC 41 (NCP1608) from a donor board made the power supply able to sustain the load and power on the PS4.
Be careful when you buy chips from ebay or alexpress guys.Leave a comment:
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EDIT 2:
putting the power supply back on the PS4 and trying to power it on, lead to the same issue of not powering on. After pressing the power button the blue led light on for a second and the it shut down.
The PS4 is fine, it works with another known good PSU.
I guess there is more issue to uncover on the faulty psu....Leave a comment:
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EDIT:
I think I found the issue!
I forgot that the 12V controller DDA001AG was not take off a donor board but isntead bought from an ebay seller who sold me also a defective NCP1608.
After watching the video that another user posted on another thread ([URL]https://www.youtube.com/watch?v=sx0oBXsueFk[/URL]) I then tried right away to extract a DDA001AG from a donor board i recently bought and guess what?
Now the 12V is stable even at 18A of load and the coil whine is gone! The voltage is not going lower than 11V and the filter capacitor voltage is 409V. Amazing!
...Leave a comment:
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Hello, I have a similar case with a PS4 power supply, model ADP-240CR.
It's story is that the PSU had the main fuse blown and the STF24N60M2 mosfet shorted.
I've then replaced it mistakenly with a 24NM60M2 that has 17 A of max drain current compared to the 18A of the STF24N60M2.
As soon as i powered the psu back on and enabled the 12V line, the 24NM60M2 bursted into pieces and damaged other components such as a tiny 50ohm resistor (R98), a diode (D63), the PFC IC controller NCP1608 (IC41) and the 12V controller DDA001AG (IC32).
After replacing those components from...Leave a comment:
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Hello,
I've stumbled across this thread because I'm trying to repair the same power supply.
in my case i have a blown Q5 mosfet. I also found that R98 and D63 are bad.
I see that D63 have the "A6" marking, googling it i found it correspond to [URL="https://www.mouser.it/datasheet/2/916/BAS316-3081362.pdf"][B]BAS316,115 [/B]diode.[/URL] Could it be?
I've read that i should check or replace the driver IC, do you know where is it in the board or the ic name?
About R98, the original value is 50Ohms, right now I only have 47 or 62 Ohms...Leave a comment:
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Finally I think I've fixed it!
What did I do:
-Retouched with flux and solder all the connectors of J8300
-Replaced U5810
-Replaced U3540 (not really necessary but it didn't have a good look)
-Retouched pins #11 and #12 of U5800 which was previously reflowed but those two pins seemed to not have a proper connection with the board.
What a journey! Thanks you all for the support and I hope this topic will help someone else in a similar situation.
Merry Christmas!Last edited by speggio91; 12-24-2023, 10:17 AM.Leave a comment:
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good board display connector diodes measurements (display attached):
1. 0.0V
2. OL
3. 0.62V
4. 0.62V
5. OL
6. 0.66V
7. 0.66V
8. 0.66V
9. 0.66V
10. 0.66V
11. 0.66V
12. OL
13. 0.0V
14. 0.63V
15. 0.58V
16. 0.58V
17. 0.0V
18. 0.50V
19. 0.50V
20. 0.0V
21. OL
22. OL
23. 0.0V
24. OL
25. OL
26. 0.0V
27. OL
28. OL
29. 0.0V
30. 0.0V
bad board display connector diodes measurements (display attached):
...Leave a comment:
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The LCD show spotlights only with the bad board. With the known good one there's nothing visible.Leave a comment:
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For lcd backlight controller you mean LP8550 (U7701)?
In the schematics I've found only BKL_SDA and BKL_SCL. Did I miss something else?
BKL_SDA = 0.554V (diode mode)
BKL_SCL = 0.553V (diode mode) and 3.3V (voltage to ground)
I've also tried to run the ASD in another good known board and that error still show up.
One thing I noticed on the water damaged board, is that on the half bottom right side of the LCD, there's a spotlight effect, that doesn't happen with the good known working board.Last edited by speggio91; 12-23-2023, 06:34 PM.Leave a comment:
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I've downloaded and ran ASD EFI 3S156 from an USB drive, I did a full test cycle and an error has been found. I've attached a picture about it. No sensor issues was found though.
I might try to remove and replace U5810, as seen in the Rossmann forum topic, even if I'm a bit skeptical that it would make any difference....Leave a comment:
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Thank you for the hints Mon2.
The trackpad i'm using belong to a known good case, I'ìve tested it with another functioning board with no issues on the sensors.
I've took some measurements for all the SMBUS scl and sda lines:
SMBUS_SMC_0_S0_SCL = 2.9V (voltage to ground) and 0.58V (diode mode). With the display connector detached the diode mode value is: 0.77V and the voltage to ground is 3.3V
SMBUS_SMC_0_S0_SDA = 2.9V (voltage to ground) and 0.59V (diode mode). With the display connector detached the diode mode value is: 0.77V and the voltage...Leave a comment:
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I've finally received some LP8550 alongside with some MMBT3904LP-7B DFN-3 (Q5158). After replacing both components the backlight is functioning properly, it only need to have its slope reprogrammed as suggested by piernov.
When the system boots, the fan is still spinning at full speed and the system is a little bit slow. I've downloaded macs fan control, but all the sensor reads good temperatures and the cpu doesn't seem to be thermal throttling.
I've tried to do the PRAM and SMC reset and they both gave no improvements.
If I startup the Macbook in SMC bypass mode, the system...Leave a comment:
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Hello again,
J6100 is completely clean, no water went on it.
In the SPI area there wasn't any water infliltration either. I've checked all the connection between all the resistors and they are all interconnected.
I've replaced U6100, U5620 from a donor board, nothing has changed.
On the bottom side of the board there is nothing that got touched by the liquid, no corrosion was found.
I've first reflowed the SMC, nothing has changed.
I've then desoldered the SMC and I've found that the pad 117 (PP3V42_G3H) is gone. I've scraped underneath...Leave a comment:
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