Compaq Presario C300 no power to inverter?

[yamada]

Hi everyone in need of some help in sorting out my laptop a Compaq Presario C300 the fault is that the left Hinge broke which cut thru screen cable and shorted out the inverter wire's orange/yellow/black, which in turn as damage the supply voltage to inverter but unable to locate which part of motherboard supply's the power and have tryed inverter in other laptop and is working ok. any help would be very helpful as i like this lappy and like to get the light back on again

[gabik111]

Re: Compaq Presario C300 no power to inverter?

Do you have schematic diagram?
Check Q31 , Q32 and Q33.
Schematic here: http://search.4shared.com/postDownlo...00_-_COMP.html

[yamada]

Re: Compaq Presario C300 no power to inverter?

Hi gabik111
thank's for your reply could you tell me where to find these's on the motherboard
thank's

[gabik111]

Re: Compaq Presario C300 no power to inverter?

Look near LCD connector.

[yamada]

Re: Compaq Presario C300 no power to inverter?

Thank's gabik111 for all your help i have found them so now need to find the part's but lease i'v got closer with your help agian thank's

[gabik111]

Re: Compaq Presario C300 no power to inverter?

Main power to inverter runs thru two coils L24 and L25 , check conector INVPWR_B+. If you got multimeter and schematic that should be easy.

[yamada]

Re: Compaq Presario C300 no power to inverter?

Hi gabik111 is the coil's in the inverter itself and not on motherboard but have checked for any power from the new ribbon that connect's to the inverter socket and did not find any volt's as the old one was damaged,inverter work's ok so the fault is on motherboard i expect from Q31 , Q32 , Q33 as you mension in last post

[gabik111]

Re: Compaq Presario C300 no power to inverter?

I did not check schematic but usually there is a fuse that securing power to the inverter.

[yamada]

Re: Compaq Presario C300 no power to inverter?

i have looked at the schematic you kindly gave but unable to see or locate a fuse on there relating to the inverter power it look,s as if Q31 as the main 5

[yamada]

Re: Compaq Presario C300 no power to inverter?

main 5v?

[gabik111]

Re: Compaq Presario C300 no power to inverter?

Right , it look like there is no fuse on inverter power source. Main power to the inverter runs thru those two coils mentioned above. This is pin 1 , 3 , 5 , 7 on LCD connector on mobo.
Q31 supply VDD voltage so it can be possible that is shorted/open.

[david34]

Re: Compaq Presario C300 no power to inverter?

Hello gabik sorry about delay in reply but think Q31 , Q32 and Q33 is what power's the screen not the inverter i will have to try to track where the inverter power come's from

[gabik111]

Re: Compaq Presario C300 no power to inverter?

Hello gabik sorry about delay in reply but think Q31 , Q32 and Q33 is what power's the screen not the inverter i will have to try to track where the inverter power come's from

Compaq C300 schematic - compal LA3342P , look at page 16 . B+ goes thru those coils and as INVPWR+ runs to LCD connector. But I'm not sure that LCDVDD+ (pin 11 , 13 , 15) is not partially connected with inverter.
I also found that two signals comes from U24 chip (page 31) , those are: INVT_PWM and DAC_BRIG and can be found on 35th and 37th pin of LCD conector (page 16).
Best Regards , gabik111