I have an 820-3435-B bought in by a customer that is not turning on. I have PP3v42 @ 3.292V, PPBUS_G3H @ 8.48V and PP3V3_S5 @ 3.298V. I do have amber light on the charger. All the other voltages are pulsing including PM_SLP_S4 as well. Any have any pointers where to start looking because, it can be caused by a horde of issues. Schematics attached.
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Schematics -
This is too low. Remove all power. Meter in resistance mode. Measure the resistance to ground of PP3v42.PP3v42 @ 3.292V
Attach the power adapter and review the voltage to ground of D7005 (each leg of this dual diode).Comment
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mon2 Resistance of PP3v42 to GND is 91.7 kOhms. A small correction PP3v42 is 3.37V. Pin 1 of D7005 is 8.48V. Pin 2 of D7005 is 0V.Last edited by bridges_4u; Yesterday, 12:39 PM.Comment
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What is the voltage to ground of ALL_SYS_PWRGD? If this signal is NOT high, then there is a fault with at least one of the monitored power rails. Is this line pulsing?
Could be a PCH / CPU fault:
https://boards.rossmanngroup.com/thr...lp_s5_l.61139/Comment
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Pulsing is either a short on one supply (or one is missing) or BIOS is not loading. Check CPU Vcore to see if comes up (as it's presence indicates all the others are ok) and if so, then check resistors around the BIOS IC for corrosion etc.
Can also be crap under the SMC or a faulty SMC too.Comment
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Hi guys ! Hope you are having a lovely day. This macbook pro came to the shop not powering on. Board is 820 - 00138. Its a macbook pro 2017 15". After disconnecting everything from the board and puting it on a charger i got 25-30mA. Right when i connect the charger i hear a click on the board. when i disconnect the cable i need to wait like for 5-10sec so the click happens again.If i put it back right away no click can be heard. I thought there may be a short somewhere but i cannot find it. so i checked power rails from the schematic. All the S5 rails were there. I think when i cleaned the... -
Hello All
I'm just starting to work on a MacBook Air 820-00165 that will not start up, I have the following measurements. Some voltages are steady while others are pulsing. There was a tiny bit of liquid spill on the board but I believe that I have cleared it up. There doesn't seem to be an obvious short on the board. The board is out and not connected to any of the normal hardware.
STEADY VOLTAGES:
PPBUS_G3H 8.59V
PPBUS_S5_HS_COMPUTING_ISNS 8.59V
PP3V3_S5 3.32V
PP3V3_SUS 3.32
PP3V42_G3H 3.41V
PPVRTC_G3H 3.32
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Hello everyone!
I have this board that got slightly water damanged and it is stuck at S5 state. It pulses once every 5 seconds.
When connected the magsafe 2 to the bench psu, the current goes from 0.02A to 0.10A when is pulsing.
When using the genuine magsafe 2 charger, the light turn on and it became green and then amber. The fan is not spinning.
When I tried the SMC bypass mode, the fan spins a quarter every 5 seconds and the pulsing is still present every time the fan spin.
The pulses are present in the CPU Vcore rails on L7320 and L7310.... -
Hi everyone!
I have a 2018 MacBook Pro (with Sequoia OS) that I've been using for years with no problem. I recently received an M2 MacBook Pro so I'm mostly using it and not the 2018 one, but since a friend of mine needs a computer, I thought I could restore my 2018 and give it brand-new-like to my friend.
I tried using the built-in tool to restore the MacBook (Settings > General > Transfer or restore > Delete) but it got stuck when trying to remove the Find Device configuration (it asked me for the password for my old Apple ID -now I use the same account but...06-27-2025, 08:54 AM -
Hi Guys
I Have this Samsung smart tv that needs repair.
with everything connected i get pulsing A5V at the PSU connector. if i unplug the main board then all voltages pulse on the output connector.
I dont get any voltage on the LED connector.
there is also an audible click around the mosfet marked below
The connector to the Buttons all voltages pulse (3v)
I have searched and found a similar problem but there was a stable 14v, but was also not repaired.
I checked and replaced the mosfets with no effect.
Any ideas where...
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