Hi to all i have a faulty a1990 from 2018, no liquid damage, died during update, now on configurator i see recovery not dfu, and i get error 9. caps around u7701 show short after removing u7701 and shorted caps still short. can any help.
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With your meter in the lowest resistance scale -> what is the exact resistance to ground of the caps noted with a short condition? If it is a low power rail, the resistance will be low by design. -
Also, be sure that you are using a quality usb cable for the dfu process. Keep it short as possible but quality- we use a cable rated for 40gbps sourced from Amazon.Comment
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I'm getting 195 omsComment
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I have use a short type c still same resultComment
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195 ohms is fine for a RAM rail. T2 has to boot before you even get into the Intel power sequence where these rails are activated.
Review the power sequence for CD3215/CD3217 on Logi wiki. If the T2 firmware is corrupted, it stops at PMU_PVDDMAIN_EN. USB C consumption should be 5V 300ma if that is that the case. Rule out T2 firmware corruption before messing with hardware!Comment
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One reason DFU will fail is shorted SSD power rails as these are quite common on A1990. Most common failures are C9091, C9093, C9087, C9098 on one side, C9586, C9588, C9589, C9593 the other. The caps are exposed to high air flows from fan intakes and often corrode.Comment
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Thanks, ive check all caps mention all good. this is a 2tb so it has all ssds populated.Comment
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on PMU_PVDDMAIN_EN, im geting 3.3vComment
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As it's in recovery, something failed in the loading of the Intel EFI process. Make sure you have 2.5V etc on power rails for the SSD's on either side. You should force it to DFU and then attempt a revive, then restore if that doesn't work.
If that all fails, you likely have an issue around the T2 PMU, the T2 itself, or bad NAND's.Comment
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