A1502 820-4924-A, e, no liquid, stop working suddenly. Yesterday, I've plugged magesafe, light green and then orange without battery,3 beeps, not turning on, CPU warm and at some point fan was spining but nothin on screen, .. no chemie.
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What is the voltage to ground of PPBUS_G3H?
Also share the voltage to ground of each pin on D7005 which is linked to the critical PPVIN_G3H_P3V42G3H and PP3V42_G3H rails. -
How could it make beeps if it's not turning on…?
https://support.apple.com/en-us/102210OpenBoardView — https://github.com/OpenBoardView/OpenBoardViewComment
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Hi
On the D7005 I have :
pin 1 - 16.13v
pin 2 - 12.54v
pin 3 - 15.86vComment
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I get 3 short beeps, a two second pause, and then 3 more beeps like before and it repeats over and over againComment
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I have already tried reflowing all the RAMs as in the video, but the problem is still there, 3 beeps.
Unlike the video on my motherboard there are 4 memory banks I unsoldered 3 leaving 1 and the problem remains. I also unsoldered the last one and the problem remains I think because without ram. I reballed 1 chip but nothing same problem.Comment
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Could it be a CPU problem? or corrupted Bios?Comment
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Remove all power. Disconnect the battery. Meter in lowest resistance scale (if manual type) or AUTO. Measure the resistance to ground of the CPU VCORE power rail. You can locate the multiple inductors (L7310/L7320) that will feed this heavy current power rail.
What is the resistance to ground in ohms at either of these inductors?Comment
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I did have an iMac once where I had 3 beeps. Initially thought it was RAM, but turned out to be a shorted PP3V3_S0 power rail from the headphone jack board. So check all your switched S0 power rails for shorts before blaming RAM itself.
These boards won't boot without all RAM IC's fitted and working. If known good RAM's and switched power rails check out, then this would be a PCH issue I would think.Comment
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Can you confirm that you are measuring the resistance to ground WITHOUT power to the board? It is not possible to measure the resistance if there is power (adapter or battery) to the logic board.Comment
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Hello again,
got an MacBook Pro from 2015, model A1502 and motherboard version 820-3476-A.
Device died over night on charger.
Currently I did the follow things:
1. Checked visuell the board, test with another MagSafe-Charger and with another DC-IN-board too
2. Measured 16,5V on PP18V5_DCIN_FUSE but 0V on ADAPTER_SENSE and 0V on PP_3V42_G3H and 0V on PPBUS_G3H but 16,5V goes to U7090
3. Because of corrosion and bad resistor values I changed these components: U7090 / C7094 / C7095 / R7095 / R7096 / L7095 / C7099 -> But further... -
Dell Vostro 5490
Service Tag: G8T7NW2
Motherboard Model: Mantis CML 18778-1
Schematics: Attached in the Google Drive folder.
BRD File: Attached in the Google Drive folder.
Video of the issue: https://youtu.be/bIXaiiub664 (Also on Google Drive)
Google Drive link: https://drive.google.com/drive/folde...j_?usp=sharing
I've attached Resistance Readings at 200ohms range. Voltage Readings, with and without power button being pressed. Detailed board pictures. Old and new BIOS files attached.
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I've got an issue with my Z820 that I'm having trouble working out the root cause of.
More often than not it'll turn onand fans will blast for a moment before stopping and I'll get 4 beeps that will repeat forever (at least the power light will keep flashing).
What I can't understand is sometimes it'll just work and I can use it all day but other times it'll boot then reboot then reboot and 4 beeps for the rest of the day. Sometimes it'll work fine from cold for hours, sometimes it'll do the 4 beeps from cold.
Another oddity is the fans. Before the 4 beeps...Today, 08:05 AM -
I've got a dehumidifier that has stopped working. Plug it in, press the power switch, and it beeps 5 times. Nothing showing in the display (which is just two 7 segment displays) apart from the two decimal points flashing. The model is a MeacoDry Arete One 18L, which seems to be a rebadged Deye (all the boards are marked Deye). Here's what I've got so far (details in case anyone else in future should need them).
Starting with the power board. Mains power comes in at the red connector top left. The compressor is powered by the orange connector to the right of that and is switched by... -
I very rarely work on macs... Received this mac, i dont know history...It seems everything is working but i have no fan spinning...I tried different fan but same thing. The problem is on FAN_RT_PWM signal... there is no voltage. On connector J6050 pin 1 and 4 voltage present, but pin 2 nothing. I checked q6060 and on r6061 the resistence seems ok. Tried nvram reset and smd reset but same thing. Also, i used the thermal camera and temperature goes to 85 C on CPU in several minutes but fan is doing nothing.
I have only two more ideas..either q5159 or something associated with cpu thermal...
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