https://photos.app.goo.gl/Xg2jZmAocXDU6XgUA here is a video. I completed a visual inspection of the logic board and did not see any obvious faults. I have checked for PPBUS_G3H @ C8008/1 and I find it cycles from 13v - 0v and back. For reference, I'm unaware there is a schematic and boardview available for the 820-00928 So I'm using the BV and schematic for 820-00281 as mentioned somewhere here on Badcaps. Where should I go next?
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Remove all power -> measure the resistance to ground of each inductor. Checking for a lower than normal resistance measurement. -
Remove the fuses (F7000 & F7001) on PPBUS_G3H and then power up again. Check if the PPBUS_G3H rail is then stable and with which voltage?Comment
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Removed F7001 and F7000 and I have steady 12.6V on pin 1 of both, and steady .6V on pin 2 of both.Comment
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Remove all power. Measure the resistance to ground of pin # 2 of the removed fuses. What is the measurement?
Next, place one meter probe on pin # 2 of the remove fuses. Other meter probe to any inductor on the board. Checking for a low resistance between the 2 points of measurement. Continue to test other inductors on the board using the same process. If you find a low resistance reading then this means the high side mosfet which functions with the ppbus_g3h rail has shorted on that buck regulator (lower voltage) rail.Comment
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Power removed, Pin 2 of both fuses resistance to ground is 38Mohms. Resistance to grond from Fuse pin 2 to inductors was ~32Mohm on all but the largest, near the battery connector, which was 22Mohm. Why does the reading change if I swap the leads' positions? Red lead to fuse pin 2, black lead to battery charging coil, .7Mohm, switch them, 22Mohm.Comment
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I got two Macbook's Pro 15" A1707 both fully working except no image on internal LCD.
I've checked and it looks like it's problem with U9850 (on both pin 1 on screen connector is 0.007 or 0.050 in diode mode)
My question is if this IC can be ordered from Aliexpress (will it work) ?? or it needs to be taken directly from donor (a1707, a1990, a2141) ?
Is this IC interchangeable (on my board i have 6142E and i found that there can be also HD3SS212) are this chips same ? ? Is it possible to find this IC on some other Macbook 13" (air, pro) ?? i have...04-25-2025, 07:55 AM -
Hi sorry to Hijack this thread, I have an A1707 820 281 which jumps from 5v -16v on amp meter then restarts, I have checked big coils for shorts, ppbus and all seems ok. Im thinking there is a short which is causing it to reboot but I'm out of ideas? Also another A1707 where the internal SSD is not showing in terminal or disk utility? No excessive heat from SSD chips?
Thanks in advance for any suggestions... -
Hi,
I'm having an issue with an A1707 MacBook Pro—there's no audio output. Initially, the MacBook came in with a no-power problem, and I found a faulty U6400, which I've now replaced. The laptop now powers on, but there's still no sound.
I've also replaced U6300, but the problem persists.
Here are the current voltage readings:- PPV18_S0: 1.8V
- R6402: 1V
- R6405: 1V
- R6403: 1V
- AUD_SPKRAMP_RESET_L: 1.3V
- PPBUS: 12.6V
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Macbook A1707 - Guys, please help newbie confirm if chip on picture is a bios one? -
Hello everyone,
I'm currently diagnosing a MacBook Pro A1707 motherboard that does not power on. I've gathered some data but am stuck and need expert advice.
Note that i'm a beginner in electronics and i'm trying to learn while trying to repair this macbook that my work gave me. I'm really curious and love understanding how thing works and i already learned so much.
Only one usb c port is taking 20v and have 12.5v on PPBUS_G3H. when trying other ports, 2 are not going to 20v and one is going to 20v but the CD3215 is getting really hot.
Observations...
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