820-2796 Green Light, No Fan

Older board but still good for practice! There is no sign of liquid damage however some test points look corroded. Its been through the Ultrasonic. Nothing gets hot to the touch or even warm.

PPBUS_G3H 8.37v
PP3V42_G3H 3.24v
PP3V3_S5 3.245v
PP5V_S5_LDO 5.026v
PP5V_S3 0v

U7201 Looks good and the voltages seem to check out except that pin 4 has 0v.
 

larossmann

Administrator
Staff member
What points are corroded? What is the resistance to ground on PP3V42_G3H? Is PPVRTC_G3H present?
 
The 5 Test points above the Y2810 are corroded, around the LVDS, by the lower SPKR AMP connector, around the sec there are a few. They are scattered around the board mostly near the edges, doesn't seem like spill damage at least not directly spilled on.

Resistance to GND PP3V42_G3H: 4.323 kOhms
PPVRTC_G3H: 3.221 @ R1920

Y2810:
Pin 1 3.221v
Pin 4 0v
 

larossmann

Administrator
Staff member
That resistance to ground combined with the location of corroded probe points leads me to believe trashed MCP89u
 

dukefawks

Administrator
There is crap under the MCP that is pulling up pin 1 of Y2810. Clean board and apply some flux and heat to the MCP. Do not reflow just let the flux cook to clear the crap. Voltages on Y2810 should be less than 1.6V.
 
Now that you mention it under the Microscope it looks like someone may have tried to reflow the CPU and MCP. Most likely they F'd it up and it needs the flip chips replaced. Gotta love some peoples attempts to repair things!
 
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