hp elitebook 6930p short

[waqas]

hello dear experts...
i have hp elitebook 6930p
when i was working on it for a usb port problem system was on position suddenly my screw driver touched on Debug port and it shorten and went off..
now its not powering on...
plz help me i m new in this field

[sanehdeep2012]

Re: hp elitebook 6930p short

PL UPDATE
either system is fully dead or powering on but no display

is there is adapter voltage is there or not,
check for shorting on all coils nr power mosfets

[waqas]

Re: hp elitebook 6930p short

system is fully dead..
no power with battery or with adopter ...
even none of led on...

i will try to check voltage give u report about that...

[Life Goes On]

Re: hp elitebook 6930p short

I think you gone need the schematic to solve that problem.

[cephei328]

Re: hp elitebook 6930p short

Hi there, have u solved the issue with your elitebook ?

[waqas]

Re: hp elitebook 6930p short

Sory for the late reply ...
I m still haveing same problem
I checked mosfits U2 and U3 working fine...
But i foun an ic UC752 near usb port section is heating up as i plug charger...
Plz guide me....

[loser18]

Re: hp elitebook 6930p short

Can't find any uc752...
What's the mobo number...

[cephei328]

Re: hp elitebook 6930p short

Hi mate, as you know laptop motherboard has standby voltages like 3.3, 5 and sometimes 12 Volts. Using lab power supply you can get greater idea of whats happening - First check 19 volts power rail (if there is a short then you will not get 19 volts out from the charger controller IC) If yes now check 3.3 and 5 Volts ALW - You noted that one of the USB controller is getting hot so there is some problem in 5 Volts rail. Remove that chip and test whether you are getting the ALW's voltages.

*If you have 19 Volts rail short then you need to check FET's and CAP's on the MAIN power rail, you can narrow down your test by simply putting your Multi tester in Ohm's range and start testing on all FET's Source's to ground - the lower the ohms gets you are getting near your target area*

Cheers

[waqas]

Re: hp elitebook 6930p short

Well thank u so much for u guidance ....
As i m new in electronics field..
I m confused how to check volts ...
Plzi guide me step by step procidure of this....
I have schematics, board, multimeter, but i have not lab power supply...
Plz guide me as i m ur student....

[fddizon]

Re: hp elitebook 6930p short

remove the chip that heats up then retest without it if it will power up

[cephei328]

Re: hp elitebook 6930p short

Well thank u so much for u guidance ....
As i m new in electronics field..
I m confused how to check volts ...
Plzi guide me step by step procidure of this....
I have schematics, board, multimeter, but i have not lab power supply...
Plz guide me as i m ur student....

Ok then! Go to page 51 :charger controller circuit - find R81 (shunt resistor) on the motherboard (usually big one) insert charger and set your multimeter to 20 volts range check 19 V on both ends of the resistor : If yes the charger controller circuit is GOOD. Next go to page 46 : System DC/DC 3.3 and 5 Volts section - find U99 IC on the motherboard Check pin 22 for 19 volts input if YES find Coil L54 (which is usually near by the chip) check for 5 ALW voltage : If no voltage at that point (remove the USB controller which is getting hot and again check whether you have that 5 Volts) Try this first and write your findings

*Well to check voltages in motherboard you need find a ground or negative rail on the board : easiest way is to put your probe in any holes provided for screwing (its copper)*

Good Luck

[cyberhack]

Re: hp elitebook 6930p short

http://www.youtube.com/watch?v=ox7kZSxKJfk have a look at this

[dabinson]

Re: hp elitebook 6930p short

pls pals help me on hp 6930p. if i switch it on, it will on and display hp logo and off. some times it won't power at all. any idea?

[LP_tekh]

Re: hp elitebook 6930p short

If you have spare parts like hdd, memory, cpu, try to swap them or start removing one by one.