 |
 |
PB G4 Alu 1,25 LCD inverter problems, no backlight.
|
|
|
|
|
Fresh-Faced Recruit
Join Date: Jun 2006
Location: Norway
Status:
Offline
|
|
Hi I was wondering if anyone knows what voltage that should be on the input and output of the inverter board. I have tried to reset the PMU,NVRAM and so on. Also tried to boot it from CD but still no backlight on the LCD. So I thought the next logical thing to do, would be to check the inverter. I have backlight on the kb so I dont think it is a logic board problem.
Thankfull for any tips,
Regards,
Kenneth
|
|
|
| |
|
|
|
|
|
|
|
Moderator  Join Date: Oct 2001
Location: San Jose, CA
Status:
Offline
|
|
The backlight for the keyboard is completely different from the backlight for the LCD. I highly recommend *not* trying to mess around with the inverter. It generates high voltage and is definitely not for a user to play around with. Chances are you've blown the fuse for the power to the inverter, which is on the main logic board. You'll need to send this in for repair or replacement.
Steve
|
|
|
| |
|
|
|
|
|
|
|
Fresh-Faced Recruit
Join Date: Jun 2006
Location: Norway
Status:
Offline
|
|
Hi Steve thank you for the advice, but I want to be sure it is the mainboard before i send it in, so I guess the safest way to measure if it is ok is to measure the voltage that comes out of the mainboard. If that is ok inverter is bad. If not the mainboard must be busted, wouldnt you agree? I am a sertified audio/video repair man, so I am not a total newbie when it comes to electronics.
Thank you
Best Regards,
Kenneth
PS: sorry if my english is bad
|
|
|
| |
|
|
|
|
|
|
|
Moderator Join Date: Oct 2001
Location: San Jose, CA
Status:
Offline
|
|
The only signals into the inverter are 5 V, GND, the PWM signal for modulating the backlight brightness, and PBUS, the main power bus for the entire system. PBUS is fused going into the inverter connector on the main logic board, so that's the fuse that probably blew.
Steve
|
|
|
| |
|
|
|
|
|
|
|
Fresh-Faced Recruit
Join Date: Jun 2006
Location: Norway
Status:
Offline
|
|
Ok thank you for the tip, is this a normal problem on the PB alu? I mean why should the fuse blow under normal use? I have not opened it yet or done anything that would qualify for a short circuit.
Best regards,
Kenneth
|
|
|
| |
|
|
|
|
|
|
|
Moderator Join Date: Oct 2001
Location: San Jose, CA
Status:
Offline
|
|
The fuse is just a safeguard to prevent bringing down the whole machine. They don't normally blow. I'm just guessing on the fuse, but it's really easy to check with a multimeter. If you don't see the PBUS voltage (I forget how much it is but it's at least over 10 V, probably around 12 to 15), and the rest of the machine is still working, it's the fuse. There's really no way to know what caused the fuse to blow.
Steve
|
|
|
| |
|
|
|
|
|
|
|
Fresh-Faced Recruit
Join Date: Jun 2006
Location: Norway
Status:
Offline
|
|
Ok a little update, I have 11.8v(PBUS) on the red wire, 2.8v on the green wire(when brightness is set to full), and 45.5mv on the yellow wire. Now I would think that the yellow wire should have 5v, so a diod or something must have blown. Ill see if I can fix it myself, will post an update. Thank you for all your help Steve.
Best Regards,
Kenneth
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
 
|
|
|
Forum Rules
|
|
|
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
|
HTML code is Off
|
|
|
|
|
|
|
|
|
|
|
|
|
Top
