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820-2936 green light with liquid damage

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protocold

Member
Board has liquid damage with obvious corrosion around C7272/C7273 and also around F7040 area. Green light. No fan spin.

U7200 generates PP5V_S5 and has 5V when measured at pin 1 of C7273.

However, when measure the same PP5V_S5 at C7801, it is only 3.05V. But when I tried to measure the continuity between pin 1 of C7273 and pin 1 C7801, they dont seem to be connected. When looked carefully the test point/circular pad that is next to pin 1 of C7273 is gone.
 
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P

protocold

Member
I have put in a jumper between and now the fan spin but stay high speed, I have got mouse led too.

But C7272 actually came off with corroded solder pad .... is it OK to leave that removed?
 
2informaticos

2informaticos

Administrator
Staff member
The board can work w/o C7272.
Shouldn't be so difficult to replace it; you can find another point to use in the same rail.

Did you test external video and USB activity?
Check CPU VCORE after 10-15 seconds; it should drop to 0.7V aprox.
 
P

protocold

Member
Yes PPVCORE_S0_CPU is 0.7v. I didnt have the heatsink on so maybe that's why it was on high speed fan.

USB mouse led only works on 1 port.

I checked L4610 was bad. Pin 3 and Pin 4 are open. However, I have replaced L4610 still no good. PP5V_S3_RTUSB_B_F = 5v.


Bad D4610 or U2600? The diode mode between the 2 data pin is 117 vs the other working port 1150
 
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2informaticos

2informaticos

Administrator
Staff member
Compare diode mode to ground readings between both ports.
Remember, red probe connected to ground; black probe at data pin.
 
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P

protocold

Member
Verified that it booted up fine with linux on usb via the good USB port [with a usb hub and mouse/keyboard attached] and also connected LCD panel and display is OK.

Diode mode reading to ground:
L4600 (good port): Pin1&2: 440 Pin3&4: 435
L4610 (bad port): Pin1&2: 459 Pin3&4: 458
 
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P

protocold

Member
I think it turns out that D4610 is bad as I was getting intermittent result... removing D4610 then the USB port is working....

Let me replace it and see what happen
 
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