[SOLVED]820-2850A shorted out on the u7000

[nate8organic]

Hi just got a computer in from a customer. he said he was changing the battery and left his screwdriver on the board it touched pin 17 on the u7000 and he said it was cherry hot by the time he found it. the chip was fried and the tab pulled up i reconnected the tab and replaced the u7000 but every time i plug in the charger it starts to fry the power io and the charger. any ideas?

Many thanks
Nate

 

[aprendiz]

Resistance to ground on F7040??

 

[nate8organic]

okay yeah the F7040 i changed out and its no longer burning up the power io. i get a green light now. but no fan or power. is it possible the u7000 i changed out got fried again from the f7040?

Thanks for the help aprendiz

 

[aprendiz]

Voltage on pin 1 from F7040???

 

[nate8organic]

f7040 .55 Volts

 

[aprendiz]

OK, Voltage on pin 2 from U7000, resistance between pin 27/28 and 17/18.......

 

[nate8organic]

u7000 pin 2 18.60v

27/28 res 10.1/10.1

17/18 res 7.0 and dropping

 

[aprendiz]

Resistance between pin 27 and 28 should be 20ohm and between pin 17 and 18 should be about 3ohm, check again.... Also check voltage on pin 3 from U7000...

 

[nate8organic]

shit yeah your right i messed up there. getting 20ohms pin 27/28

2.8-2.9ohms 17/18

 

[nate8organic]

oh also pin 3 on u7000 is 4.47V

 

[aprendiz]

ok, for me is a bad U7000 or not properly soldered

 

[nate8organic]

okay very possible its bad. donor boards ya know. i will pull it off make sure it was on good and try another one.

 

[nate8organic]

checked the u7000 and swapped it out. still the same green light no power.

 

[aprendiz]

Resistance to ground on F7040'???

 

[nate8organic]

what should it be if there is no res to ground?

 

[aprendiz]

If there is not low resistance there is somethig wrong on ISL, maybe bad or not soldered properly....

 

[dukefawks]

Using the correct ISL 6259 not 6258?

 

[nate8organic]

Yeah no i def did not have it soldered good. checked it out real quick and one of the tabs was not connected. cleaned it up and re seated it and alls good. Thanks for the help Aprendiz and thanks for dropping in duke, that answered a questions i had about using a dif ISL.

Thanks again!