Also covered more in depth in RepairWiki
https://repair.wiki/w/Apple_ACE2_Controllers
reformatt
Badcaps Legend
Last Activity: Today, 05:49 AM
Joined: 02-17-2020
Location: Noosaville
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If you don't have an USB-C ammeter or tail tester, or you don't have any use in the future to get them, maybe another board is the go. If you are only getting 5V and slow charging, then it's likely one of the CD3217's is probably damaged.
USB-C controllers on MAC's are a bit of a PITA, but you can use new (i.e. unprogrammed) CD3217's on this board. I did a write up on CD3217 I2C programming if you care to look at it, but suffice to say that these boards I2C addressing is as per the strapping on the board.
https://www.badcaps.net/forum/troubl...hardware-devic...Leave a comment:
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CD3217 and I2C addressing
This was going to be a short post, however I thought I'd write this up as I haven't seen a deep dive like this. I began writing this up for an A2337, but think this deserves its own post for my memory and any corrections that may or may not be needed.
A good video describing the straps for CD3217 I2C addressing:
https://www.youtube.com/watch?v=MV39IbgPiYc
So which CD3217 is needed for a A2337 MAC or for others for that matter? Here is the addressing map for TPS65982 since we don't have datasheets for the CD chips and it appears to be the same anyway.
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First thing to do is examine the USB-C connectors themselves for burning or damage, especially if you are using a 3rd party cable. You can remove the connector flex without removing the board, just takes a little manipulation and patience.
Next is to examine the response from the USB-C ports via a USB-C ammeter and an Apple charger. Should start at 5V, negotiate to 20V and charging current should then be 2 amps or so. A USB-C tail tester is useful here for comparing diode values of each pin to check if you have damage to one of the CD3217's. Usually I do diode checks around each controller...Leave a comment:
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You only need to run a jumper if that pad is destroyed or it's open circuit to D7701. For future reference, just jumper to one of the test pads that are on the same side of the board. They connect via XW7720 which is just a shorting pad so they are electrically connected.
BKL_EN should be high at the junction of R7731/R7715, and you need a valid BKL_PWM signal as well - you will only get these with a display connected. If you don't have an oscilloscope, this should at least be a non-zero value with a DC meter - you could do a PRAM reset to ensure brightness...Leave a comment:
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If you want to manually rebuild the BIOS, you download the EXE from the Dell support site, and extract it using Biosutlitlies from Github.
https://github.com/platomav/BIOSUtilities
There are two BIOS for this model relating to platform ID I think
BIOS-UEFI [0x015A457F-0x025A457F].bin
BIOS-UEFI [0x0030BB4E-0x0130BB4E].bin
Both files are identical though when compared in HxD and 16,384KB in size. Since this is a AMD platform, there is no ME region to care about. Copy in your DMI and Windows key info (check here) and you are set.
...Leave a comment:
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U7701/L7701/D7701 is a boost converter circuit using PPBUS_G3H voltage via F7700/Q7706. If you have 8.6V volts for the backlight, then there is no switching coming from U7701. As I said, if your enable is there, and the IC isn't switching, then your problem is around U7701 itself or the connections to it.
There is often corrosion under this IC as the bottom of these boards are exposed to the rear and cop it from the air intake. In some cases, ball A5 (the feedback pin which takes the most current) is often badly corroded and you need to run a jumper from the test pad nearby. Diode...Leave a comment:
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Just as a follow up, this machine sat on my shelf for a few days blinking away. When I put it on the bench (and plugged in the charger), it went though a CMOS reset and booted ok. When it got to Windows, battery percentage was 89%. I thought, why was it going through a CMOS reset then if battery had charge?
So my +3V RTC voltage is derived from your typical dual diode arrangement between the CMOS battery and the +3V LDO (which is derived from the main battery). The CMOS battery for this machine is within the main battery itself and subsequent tests showed this battery died very quickly....Leave a comment:
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There is no enable pin on the connector for the BMS so you should have voltage on the main terminal at all times. As its 0V that means the internal cells are below threshold and it's been disabled by the BMS. Battery has been on the shelf too long and the cells have discharged.
So just a faulty battery....Leave a comment:
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Hot air is the easiest. Heat from underneath with a large nozzle and high air flow. In confined spaces with plastic nearby I mask those areas with kapton tape and then cover it again with copper tape. I replaced an EC on a Lenovo board that was right in between two ZIF connectors with this method. Copper tape makes it much easier.
You can use low melt solder on the pins to make it a bit easier. Chipquik is the best but expensive. You can get rolls of low melt alloys though - not as good as Chipquik but cheaper. Then I use hot air and a manual solder sucker to clear the holes. Some...Leave a comment:
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Show a pic of the SVOD4 log. If the EC is being detected,. that eliminates the connector pin out etc. Press Read ID, Config Nuvoton twice before you do the read. If you only do this once, then you won't get data - that is the bug I reported.Leave a comment:
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If you have 8.6V on the output, it means the backlight inverter isn't working. Should be around 25V. If BKL_EN is high, it's often a bad U7701 or corrosion on pin 1 of that IC.Leave a comment:
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I reported this as a bug for SVOD4 for NPCE68BPA0DX on L14 GEN 2 last year. AFAIK, it's not been fixed but I found a workaround for it to read quick with valid data:
1. Config Nuvoton (select read size)
2. Read ID
3. Config Nuvoton (select read size again as the software will reset it back to it's default - for this model I need 384kb)
4. Read
IIRC, had to have the battery connected on this model for it to read the EC as well, in addition to USB-C power. You need the RTC battery connected otherwise it will attempt to auto-boot from a CMOS reset....Leave a comment:
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Check continuity of FU2
...Leave a comment:
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I had an A2442 in recently where it would not power on after it was shutdown. Same behaviour, it wouldn't restart till the battery BMS cable was removed or SYS_DETECT was temporarily shorted. The behaviour I saw was 5V>20V>0V looping on USB-C. It would boot perfectly fine after BMS removal/reinsertion, charge fine, and run off the battery. If you shut it down, it would continue to charge until you pressed the power button or opened the lid. I also noted that it wouldn't power off after shutdown with battery disconnected (and would restart on its own). I replaced a battery on another A2442...Leave a comment:
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I don't waste too much time on Lenovo's with this kind of behaviour as it's usually bad balls under the CPU. This is particularly true on Legion laptops. Do an initial board inspection for corrosion, loose pins on RAM slots and then observe input current without battery, with RAM and without. You only need one bad ball for it to hang or not POST.
It's not something unique to Lenovo, as I see it on other brands too, but not to the extent I see it on this brand. Lenovo also put black glue under the corners of most of their chips, and it's not an easy thing to remove without board damage....Leave a comment:
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From that boardview/schematic, 3CL2 is a decoupling capacitor. It smooths out fluctuations on the on the +VBATA supply rail so it's not cause of your issues.
Faulty devices off eBay are a mixed bag. If it's from a refurbisher/repair shop, it will often have more than one fault since it will have been used to repair other laptops and faulty parts swapped into it. Resolve all unknown devices in Device Manager first before troubleshooting first. With regard to the GPU, if it's bad balls etc it should still be identified under display adaptors even if the driver isn't loaded. More likely...Leave a comment:
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Boardview is correct, RE49, RE56, RE77, RE52 are 0 ohm and are just copper pads on the board instead.
RE32 is a 100K pullup to +3V for the LID_360_SW_N logic line. If it's low, the machine will be in tablet mode I would surmise. So the problem is either the sensor is faulty in the lid or a damaged LCD cable.Leave a comment:
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From the boardview, I don't see how that IC is related so I am not following your logic. What is the voltage at RE32/RE56? To me, this is a logic low if the tablet mode sensor is triggered.
In WIndows 10, there used to be a button in Action centre to display whether it was in tablet mode or not, but it's been removed in Windows 11 and the function is automatic. You might try installing Windows 10 to confirm the issue is indeed Windows converting to tablet mode before you go down a rabbit hole.
I note there is also a tool for Yoga laptops called 'Lenovo Yoga Mode Control...Leave a comment:
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The EC code is usually in the first padding block in the BIOS region when you examine it in UEFI tool. You can extract that section and trim it to 192kb with a hex editor. Or just use ECfinder to extract it from the BIOS. You can compare what it extracts vs manual extraction with UEFI tool to see if you got it right
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