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820-00850 5V On Charger

brunomotter

brunomotter

Member
Hello. Got this board here. UB300 was boiling hot, so I replaced it. When I removed the chip PAD number 4 was ripped off, so I ran a jumper wire through it. Some other pads have been ripped, they are 7 and 8, but no big deal, since pins 6 and 18 which are connected to them are integer and conducting well. No I get 5V on all ports, but all of them except the one I replaced UB300 is drawing around 250mA from charger. UB300 negotiates 5V but draws 0A from charger. I have no visible blown components and no shorts I could find. Any ideas?
 
2informaticos

2informaticos

Administrator
Staff member
Compare diode mode readings between UB300 and other chips.
Can have bad solders, or bad/fake chip; if bought "new" from China.

BTW, can you put the machine in DFU mode?
 
brunomotter

brunomotter

Member
If tested on each respective fuse, all of them give 0.168 on diode mode. Machine enter DFU, but does not complete restore.
 
brunomotter

brunomotter

Member
I gave some reflows to UB300 and now all ports behave the same. 250mA power consumption with 5V. I noticed something strange...
PP1V8_UPC_TA_LDOA is giving me 3.3V instead of 1.8V
 
brunomotter

brunomotter

Member
Replaced UB300 AGAIN from donor board. Still same thing... It's not possible I got 3 CD3215 with literally the SAME defect. The strangest thing is that UB300 corresponding port communicates with charger and requests 5V but if I reverse the cable it does not negotiate anything with charger. I don't know what to do anymore.
 
brunomotter

brunomotter

Member
I noticed something strange here. All ports, except for the UB300 port read the same on CC1/2 respective lines, which is around 1.6V on their respective RB. For example, on RB650 I get 1.6V and RB660 0V, when I reverse the cable, RB650 gets 0V and RB600 gets 1.6V. On RB640 and RB630 on the other hand, I get 5V on RB640 and 1.6V on RB630 and reversing the cable I get 0V on both. I think the problem may be there.
 
2informaticos

2informaticos

Administrator
Staff member
You may have bad UB300 , or problem on the corresponding USB-C terminals.
Remove the USB-C port from shell and inspect the terminals.
 
brunomotter

brunomotter

Member
All terminals are good, already inspected them... But this is the third or fourth UB300 I put on the board... Tried with new and donor ones... All behave the same
 
brunomotter

brunomotter

Member
What would you suggest then? I'm out of ideas already... Thinking about throwing this piece of shit on the litter bin.
 
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