Hello, I've got an issue with 820-00928 (15" 2017), it came to me dead. Board has no corrosion, but someone obviously reflowed or maybe replaced U7000 and CB704 - I guess that's because Louis did this in one of his videos (it's funny how often I'm getting boards from other repair shops where they did exactly the same thing that Louis did with the same board... even if it's a completely different issue, only with similar symptoms). However there is no problem with PPBUS_G3H, so I guess this part is fine.
I measured and found a short on PP3V3_TBT_T_S0 through UB000. After removing UB000, the short is gone, the board boots and partially works. However when I soldered "new" UB000 (from 820-00840 as I don't know where to buy a whole 820-00928 with this chip, or the chip itself), it shorted again after connecting the power supply. So I removed UB000 again and measured every pin of UB000 - nothing is shorted in there. Area around U5670 looks untouched. PP3V3_S0 works flawlessly with UB000 removed (and with bad UB000 it's partially shorted, that's why the machine cannot turn on I guess).
I've got one last UB000 from 820-00840 and I don't want to waste it the same way as the first one, what else should I check?
Thank you
I measured and found a short on PP3V3_TBT_T_S0 through UB000. After removing UB000, the short is gone, the board boots and partially works. However when I soldered "new" UB000 (from 820-00840 as I don't know where to buy a whole 820-00928 with this chip, or the chip itself), it shorted again after connecting the power supply. So I removed UB000 again and measured every pin of UB000 - nothing is shorted in there. Area around U5670 looks untouched. PP3V3_S0 works flawlessly with UB000 removed (and with bad UB000 it's partially shorted, that's why the machine cannot turn on I guess).
I've got one last UB000 from 820-00840 and I don't want to waste it the same way as the first one, what else should I check?
Thank you