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820-3437 liquid on u7501 and u1900

I

ielectron

Member
i replaced u7501 (new chip)and u1900 (from donor board), there is green light, i can do SMC reset
-the board takes 0.380A when i connect the charger, than that goes back to 0.200A and stays there

i see no water else where, only on those 2 chips, and some resistors around, i replaced all of them, no here is the measurement for

u7501
[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[TD="width: 64, align: right"]1[/TD]
[TD="width: 64, align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]1.245[/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]5[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]1.998[/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]9[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]10[/TD]
[TD="align: right"]1.998[/TD]
[/TR]
[TR]
[TD="align: right"]11[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]12[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]13[/TD]
[TD="align: right"]1.998[/TD]
[/TR]
[TR]
[TD="align: right"]14[/TD]
[TD="align: right"]5[/TD]
[/TR]
[TR]
[TD="align: right"]15[/TD]
[TD="align: right"]1.96[/TD]
[/TR]
[TR]
[TD="align: right"]16[/TD]
[TD="align: right"]1.01[/TD]
[/TR]
[TR]
[TD="align: right"]17[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]18[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]19[/TD]
[TD="align: right"]1.99[/TD]
[/TR]
[TR]
[TD="align: right"]20[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]21[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]22[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]23[/TD]
[TD="align: right"]8.57[/TD]
[/TR]
[TR]
[TD="align: right"]24[/TD]
[TD="align: right"]4.01[/TD]
[/TR]
[TR]
[TD="align: right"]25[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]26[/TD]
[TD="align: right"]8.33[/TD]
[/TR]
[TR]
[TD="align: right"]27[/TD]
[TD="align: right"]1.1[/TD]
[/TR]
[TR]
[TD="align: right"]28[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]29[/TD]
[TD="align: right"]5[/TD]
[/TR]
[TR]
[TD="align: right"]30[/TD]
[TD="align: right"]4.8[/TD]
[/TR]
[TR]
[TD="align: right"]31[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]32[/TD]
[TD="align: right"]0[/TD]
[/TR]
[/TABLE]



u1900
[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[TD="width: 64, align: right"]1[/TD]
[TD="width: 64, align: right"]0.135[/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]3.27[/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]0.004[/TD]
[/TR]
[TR]
[TD="align: right"]5[/TD]
[TD="align: right"]3.28[/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]1.19[/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]1.19[/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]0.34[/TD]
[/TR]
[TR]
[TD="align: right"]9[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]10[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]11[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]12[/TD]
[TD="align: right"]0.125[/TD]
[/TR]
[TR]
[TD="align: right"]13[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]14[/TD]
[TD="align: right"]3.29[/TD]
[/TR]
[TR]
[TD="align: right"]15[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]16[/TD]
[TD="align: right"]0[/TD]
[/TR]
[/TABLE]
 
I

ielectron

Member
in the meantime i found another good board, the measurement for this
[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[TD="width: 64"]u7501[/TD]
[TD="width: 64"] [/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[/TR]
[TR]
[TD="align: right"]1[/TD]
[TD="align: right"]5.5[/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]5.1[/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]1.25[/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]3.33[/TD]
[/TR]
[TR]
[TD="align: right"]5[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]1.996[/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]9[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]10[/TD]
[TD="align: right"]1.996[/TD]
[/TR]
[TR]
[TD="align: right"]11[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]12[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]13[/TD]
[TD="align: right"]1.996[/TD]
[/TR]
[TR]
[TD="align: right"]14[/TD]
[TD="align: right"]5[/TD]
[/TR]
[TR]
[TD="align: right"]15[/TD]
[TD="align: right"]1.97[/TD]
[/TR]
[TR]
[TD="align: right"]16[/TD]
[TD="align: right"]1[/TD]
[/TR]
[TR]
[TD="align: right"]17[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]18[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]19[/TD]
[TD="align: right"]1.996[/TD]
[/TR]
[TR]
[TD="align: right"]20[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]21[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]22[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]23[/TD]
[TD="align: right"]8.59[/TD]
[/TR]
[TR]
[TD="align: right"]24[/TD]
[TD="align: right"]3.59[/TD]
[/TR]
[TR]
[TD="align: right"]25[/TD]
[TD="align: right"]3.34[/TD]
[/TR]
[TR]
[TD="align: right"]26[/TD]
[TD="align: right"]8.44[/TD]
[/TR]
[TR]
[TD="align: right"]27[/TD]
[TD="align: right"]0.38[/TD]
[/TR]
[TR]
[TD="align: right"]28[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]29[/TD]
[TD="align: right"]5[/TD]
[/TR]
[TR]
[TD="align: right"]30[/TD]
[TD="align: right"]0.38[/TD]
[/TR]
[TR]
[TD="align: right"]31[/TD]
[TD="align: right"]10.17[/TD]
[/TR]
[TR]
[TD="align: right"]32[/TD]
[TD="align: right"]5.1

[/TD]
[/TR]
[/TABLE]


[TABLE="border: 0, cellpadding: 0, cellspacing: 0"]
[TR]
[TD="width: 64"]u1900[/TD]
[TD="width: 64"] [/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[/TR]
[TR]
[TD="align: right"]1[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]1.2[/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]1.09[/TD]
[/TR]
[TR]
[TD="align: right"]5[/TD]
[TD="align: right"]3.33[/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]1.19[/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]0.56[/TD]
[/TR]
[TR]
[TD="align: right"]9[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]10[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]11[/TD]
[TD="align: right"]0[/TD]
[/TR]
[TR]
[TD="align: right"]12[/TD]
[TD="align: right"]0.391[/TD]
[/TR]
[TR]
[TD="align: right"]13[/TD]
[TD="align: right"]3.4[/TD]
[/TR]
[TR]
[TD="align: right"]14[/TD]
[TD="align: right"]3.3[/TD]
[/TR]
[TR]
[TD="align: right"]15[/TD]
[TD="align: right"]1.66[/TD]
[/TR]
[TR]
[TD="align: right"]16[/TD]
[TD="align: right"]0[/TD]
[/TR]
[/TABLE]
 
I

ielectron

Member
so my u1900 is not giving 3.3V on the leg 1, so the crystals are not working? the leg 1 was corroded, i removed it, pad cleaned, chip replaced, but still no 3.3
 
2informaticos

2informaticos

Administrator
Staff member
Did you check resistance to grounat pin 1/U1900?
If OK, then check for 3V at pins 2 & 13 of U1900.

25MHz will not appear untill board starts.
You must get first 32KHz at pin 12.
 
J

JohnB8812

New member
If you have a short on pin 1, you need to remove U1900 first to see if it goes away. If not, the cap next to it can cause the short. If not that, there are 4 other big caps on the board for RTC. If you remove all 5 caps and U1900 and it’s still 1 ohm, then yes dead CPU
 
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