Patrick501
Member
Last Activity: 04-17-2025, 01:36 AM
Joined: 10-29-2024
Location: west
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Thank you for the confirmation.. sad, but it's kinda like what I expected... -
Thanks for your answer. Do you mean another rail instead of PPBUS_HS_CPU to measure?
PPBUS_G3H is conntected to PPBUS_HS_CPU by the R5400 (pic in my first post). So this should always be about 0 ohms. That's why I removed The R5400 yesterday to make figure out which rail causes the short.
Is the U7420 the high side mosfet you mean? The L7420 shows 8 ohms to PPBUS_HS_CPU. You're probably right that this Mosfet is defective or leaking....Leave a comment:
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I removed the cooling shields of the GPU/CPU and when I inject 1V into PPBUS_HS_CPU, the CPU heats up.
Doesn't look too good thoLeave a comment:
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MacBook A1990 PPBUS_HS_CPU short
Hello everyone,
I have a A1990 which had a blown inductor next to the display connector. There was no short at this spot, so I replaced it.
I noticed that the big coils above the GPU/CPU (PPVCORE) had a pretty low resistance (2.2Ohms). I already talked about this with mon2.
PPBUS_G3H, PPBUS_HS_CPU showed 1.8ohm to gnd. So I removed the R5400 to seperate the two rails. PPBUS_G3H is fine again but the short is unfortunately on PPBUS_HS_CPU. Sounds like a no fix to me.
Plus I can't find any particular spot which his heats up when I inject 1V@max2A
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The EC came today and I replaced it. Unfortunately still not powering up, no 20V.
5V@0A
I don't wanna give up on this one, so I would appreciate any help I could get.Leave a comment:
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Same thing with the right inductor. So the U8100 needs to be replaced.Leave a comment:
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I replaced the inductor by a wire. The PP5V_BSTLQ_VOUT_MPMU has 3.7V (instead of 5V) now and the U8100 is heating up.
To me, it seems like it has an intern short. The other caps are ok. I desoldered them to check but still 20ohms.
Only a bad cap would've been too easy...Leave a comment:
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I have 3.8V going into the inductor but around 0.3V coming out. It should have a very low resistance but 14K is far away from being an inductor.
I just removed the cap which became hot. Now I have 20 ohms instead of nothing..Leave a comment:
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damn, good one [USER="295753"]mon2[/USER] ...PP5V_BSTLQ_VOUT_MPMU is 0 ohms
and the L8300 is a cap instead of an inductor. That's weird.
EDIT: I turned the brightness a bit down. The color of it is slightly different. It's an inductor but I measure14K. There's definitely something wrongmon2...Leave a comment:
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120K / 0.357V diode
I checked it again. The U8100 not heating up....Leave a comment:
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I have a question before I start trying to do this.
Does it even make sense when there's no VCC voltage at the U1970?...Leave a comment:
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Unfortunately, I couldn't find a cheap similar board.. But if I find someone around here with an adapter, I will try to flash the firmware tho. Since it's not my own macbook, I'm not gonna spent 200 bucks on the adapter for this one time job which might not have a positive outcome.
I hate to give up on repairs, so that's probably why I'm still on it. I recently had a macbook where repair wiki said it was a no-fix and I almost send it back to the customer.. It's working now...Leave a comment:
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thanks for the link. I might give it a try.
Do you know if the DFU mode is only possible when the S2 rails are present since it wasn't possible for me to get into DFU by a second Macbook?...Leave a comment:
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I assume the only possibility to do this is the way it was done here?
[URL]https://www.youtube.com/watch?v=u4-66f6RFPM[/URL]https://I assume the only possibilit...6RFPM[/URL]I assume the only possibility to do this is the way it was done here?
[URL]https://www.youtube.com/watch?v=u4-66f6RFPM[/URL]...Leave a comment:
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I know what you mean, t's an unidirectional. I use it either with adapters or put it straight into the USB power supply to keep it in the right direction, 5.1V@V0,00A...Leave a comment:
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for anyone who has the same issue. I don't have a solution yet but meanwhile I checked the power sequences to get 20V.
Everything is fine until it reaches the U8100/U7700. There are no output signals, so apparently the sequence ends there. I also checked resistances of the missing output rails./ second step in diode mode.
35 ohm seems low but for a cpu rail it should be ok....Leave a comment:
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mon2[USER="295753"]mon2[/USER]
thanks for the schematics. Unfortunately is has no numbers for the sequence like the one for the A2338 but I will try to figure this out.
For some reason I get private messages without text. Do you know what's wrong there?...Leave a comment:
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I have the voltage (green) on the coil like in den video but no standby voltages in the red area.
Only the PP3V8_AON_VDDMAIN seems present...Leave a comment:
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[B]I2C_SMC_PWR_3V3_SDA: 3.3V
I2C_SMC_PWR_3V3_SCL: 3.3V[/B]
3.3V both
yes it's 3.43V on both now. I just double checked with another multimeter.[B]I2C_SMC_PWR_3V3_SDA: 3.3V
I2C_SMC_PWR_3V3_SCL: 3.3V[/B]
3.3V both
yes it's 3.43V on both now. I just double checked with another multimeter....Leave a comment:
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according to this link and the one for the A2337 it could be a bad U8100.
PPBUS_AON is also a bit low by 12.28V /diode mode 0.527V
I did a DFU twice, but this one won't connect. I also tried different USB ports. I think you can only use the two ports connected straight the logic board. Not sure though... neither of them worked
there are the voltages of both CD3217. (USB-C connected to UF 400 first, then UF500)...Leave a comment:
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