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[SOLVED]820-4929 running slow

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Fizzl92

Member
This 820-4929 turns on. It starts and boots normally but after the bar under the apple logo has reached ~50% it gets really slow. If i wait a few minutes the bar completes but it stays at the apple screen forever. The customer provided a picture of an error message. This includes the message

AppleUSBHostPort::InterruptOccurred: overcurrent detected

and other (for mee) confusing numbers. There was a little bit of flux by U7200 but besides this and a warranty sticker the board looks fine. It also shows the same behaviour when i try to boot from a USB drive. I have no idea where to start on this one.
 
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Fizzl92

Member
Bios chip looks like new. Diagnostic gives me 2 warnings. The battery should be serviced and there may be a problem with the fan - even if the fan is working fine...
 
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Fizzl92

Member
Same thing with battery unplugged. It also needs really long (~30 sec.) after i turn it on until it "dongs"
 
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Fizzl92

Member
ok, thank you. I had no idea as this is not the case with the older boards... I ordered a battery for this one as i have no one here because they are still pretty expensive...
 
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Fizzl92

Member
New battery arrived today but no change. I also still get the Battery warning if i run diagnostic. The battery i ordered was 100€ and from a vendor i know and trust so i think ist pretty unlikely that the new battery is also bad.
 
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dukefawks

Administrator
Battery warning is common and usually does not have any effect on performance. Can the machine boot from only the battery?
 
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dukefawks

Administrator
Is the only error reported in the onboard test the battery one? How does the battery report in OSX or does this not boot into OSX at all?

Only other thing I can think of is corrupted ME region. Read the original chip and post the dump here.
 
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Fizzl92

Member
It also says that there may be an error with the fan - but fan works normally as far as i can tell. The problem is that it never finishes loading. If its off and i press the power button it needs around 30 sec. to chime. Then the apple loads normally up to ~50% and from there on it loads really slow until the bar under the apple is full. But it never finishes loading. It stays in the Bootscreen with the full bar under the apple. Should i try new Bios to see if something changes?
 
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Fizzl92

Member
I removed and saved the old Bios. After that i took a Bios IC from a china board, erased it and programmed the file you send me to it. Now the device boots up normal. I also uploaded the Bios File from the original IC here.

https://drive.google.com/file/d/0B5EhUh5agFcuU3E1WFdLek9rbUo3OHZPY3BqYmpDYmxHZFY0/view

Unfortunately one USB Port is not working and its J4600. So the warning from the beginning

"AppleUSBHostPort::InterruptOccurred: overcurrent detected"

the customer told me about was really a board issue. Could this kill the BIOS?
In guest mode it once gave me the warning that i should unplug the USB device that is draving to much power. But there is nothing plugged in to J4600. The port looks fine and i get 5.16V at Pin 1.
 
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dukefawks

Administrator
Download link does not work.

USB over current has nothing to do with the BIOS. Check all 4 USB current sense input to the PCH at XDP_USB_EXTA_OC_L same for EXTB,EXTC,EXTD. One of them will be low
 
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Fizzl92

Member
I have no idea why but the link only works if you copy it and paste it manually in the browser. Sorry about that.

is pulsing between 0.9 V and 1.3 V
XDP_USB_EXTB_OC_L is 3.3 V
XDP_USB_EXTC_OC_L is 3.3 V
XDP_USB_EXTD_OC_L is 3.3 V

As i was measuring i found what is shown in the attached picture. Seems like someone else messed with it before... R1580 (XDP_USB_EXTA_OC_L) is one of the resistors in the picrure...So i fixet that mess, run a jumper, put a missing resistor back on and J4600 is working again. THANK you very much! So if it gets back its original Bios this one should be fixed!
 

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