[SOLVED]MacBook Pro 13" 820-2936 Early 2011 both USB ports dead - no liquid damage

[razorwoods]

[SOLVED]MacBook Pro 13" 820-2936 Early 2011 both USB ports dead - no liquid damage

[h=2]Working on a MacBook Pro 13.3" - Early 2011 logic board that has both USB ports dead.[/h] Everything else seems to work properly and it's otherwise a very normal A1278. Inspection under a scope shows absolutely no signs of liquid damage, obvious burns on the board or probe points.

I've already tested the usual L4600 & L4610 suspects and have both have good continuity. Any tips on where I should look next would be much appreciated.

 

[dukefawks]

Is there 5V power from the ports? USB HDD spinning up? Diode mode on both data pins of the ports?

 

[razorwoods]

5V is not present on either USB port.

 

[dukefawks]

Check around U4600, is 5V getting to it? Is the enable present? Is there a short on the 5V rail after U4600? Could be just a bad U4600.

 

[razorwoods]

U4600 has 5V present on pins 2 & 3 and 2.3V present on pins 6 & 10

 

[dukefawks]

pins 4 and 5 are 3v? No short on output pins 8/9? Probably bad U4600.

 

[razorwoods]

Yes pins 4 & 5 are 3V , pins 2 & 3 are 5v, no short on pins 8 or 9. Bad U4600 ?

 

[razorwoods]

Replaced U4600 and both ports are working normally now. Thanks for the guidance.