Hi All.
Just wanted to see if I can get some assistance with a A1708 I'm working on. Board while looking clean had it's liquid marker tripped by U2890. Board started off as fluctuating between 0.0157A @ 5.1762V to 0.0132A - 5.1751V 0.190A. Went through and checked the CD3215 bootup table on logiwiki. Found all LDOs (step 2) are present bar P1V1_UPC_XA_LDO_BMC which is completely missing regardless which USB port I use and P1V1_UPC_XB_LDO_BMC which is 0.280V, Logiwiki noted that's likely a faulty TBT rom, and judging the sticker near it had tripped I decided to remove the rom and low and behold there was junk under it. Replaced it and now the boards up to 0.0230 with a short dip to 0.01 and a short spike to 0.04 than rinse and repeat.
After replacing the TBT rom it shortly did get warm, not hot but it was evaporating IPA after maybe 40 sec or so, but after leaving it on for a minute or so and power cycling it's no longer doing that. Nothing else seems to be getting hot. Confirmed all traces between the TBT rom and the CDs are ok, as logi also mentions they often break.
What else could be causing PP1v1 to be missing? Besides bad CDs hopefully because I do not have replacements.
Thanks for your assistance.
Just wanted to see if I can get some assistance with a A1708 I'm working on. Board while looking clean had it's liquid marker tripped by U2890. Board started off as fluctuating between 0.0157A @ 5.1762V to 0.0132A - 5.1751V 0.190A. Went through and checked the CD3215 bootup table on logiwiki. Found all LDOs (step 2) are present bar P1V1_UPC_XA_LDO_BMC which is completely missing regardless which USB port I use and P1V1_UPC_XB_LDO_BMC which is 0.280V, Logiwiki noted that's likely a faulty TBT rom, and judging the sticker near it had tripped I decided to remove the rom and low and behold there was junk under it. Replaced it and now the boards up to 0.0230 with a short dip to 0.01 and a short spike to 0.04 than rinse and repeat.
After replacing the TBT rom it shortly did get warm, not hot but it was evaporating IPA after maybe 40 sec or so, but after leaving it on for a minute or so and power cycling it's no longer doing that. Nothing else seems to be getting hot. Confirmed all traces between the TBT rom and the CDs are ok, as logi also mentions they often break.
What else could be causing PP1v1 to be missing? Besides bad CDs hopefully because I do not have replacements.
Thanks for your assistance.
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