PowerBook G4 1,67 Hires no video output on LCD

[Nameci]

I have a powerbook g4 1,67 hires that the screen has been damaged. I bought a replacement panel from ebay. It was declared as a pull from a working system.

After installation, I only get the backlight on but there is no video coming out from LCD panel. Do I need to reset the PRAM in this case?

I am using an external monitor and it boots into the desktop fine.

 

[MacForScience]

I have a powerbook g4 1,67 hires that the screen has been damaged. I bought a replacement panel from ebay. It was declared as a pull from a working system.

After installation, I only get the backlight on but there is no video coming out from LCD panel. Do I need to reset the PRAM in this case?

I am using an external monitor and it boots into the desktop fine.

Did you consider the fact that you bought it from Ebay, from a total stranger, who may not have been totally honest or was sloppy on the care of the screen etc.?

Your PRAM isn't your issue. Did you carefully check the wiring harness on the screen etc. You could also try running hardware test to see if it tells you anything. My guess bad hardware.

Cheers

 

[Nameci]

I am still in contact with the seller. I tried everything I can, reopened it and reseat the connectors, still blank black screen with the backlight on.

 

[666sheep]

Original screen was mechanically damaged or had the same issue as replacement one? Product numbers are matching between them (i.e. are you sure you did buy the right one)?

You can try to check if it's properly recognized by your PB.

copy followed text to Terminal (in one line):

ioreg -lw0 | grep IODisplayEDID | sed "/[^<]*</s///" | xxd -p -r | strings -6

It should spit-out LDC model, like this:

LP171W01-A4K2
Color LCD

NVRAM reset via OF also shouldn't hurt

 

[Nameci]

Original screen cracked during shipping. Replacement screen issue is different. Replacement screen is just black with backlight on.

I have contacted the seller and he is sending me a replacement one. He told me that they have tested it to be working but I doubt.

Yes I am sure I did buy the right one.

 

[Nameci]

Original screen was mechanically damaged or had the same issue as replacement one? Product numbers are matching between them (i.e. are you sure you did buy the right one)?

You can try to check if it's properly recognized by your PB.

copy followed text to Terminal (in one line):

ioreg -lw0 | grep IODisplayEDID | sed "/[^<]*</s///" | xxd -p -r | strings -6

It should spit-out LDC model, like this:

LP171W01-A4K2
Color LCD

NVRAM reset via OF also shouldn't hurt

It spits;
LTN152W6
Color LCD

How can I go to open firmware main LCD is not working. What will I do to make external as main monitor?

 

[666sheep]

How can I go to open firmware main LCD is not working.

Sorry for late answer. Just press cmd-opt-n-v (like PRAM reset) at boot.

If all tricks will fail and all connections, ribbons cables etc are OK - nothing more to do IMHO. Wait for another screen if seller wants to send you one.

 

[Nameci]

I am on the field right now, so I cannot install the replacement screen. I wil see it in a couple of days.

 

[Nameci]

So the replacement arrived. Installed it and it is with the same result. No video on the LCD panel, the backlight is on. And video is out on the external DVI.

I guess it could be the logic board? In the system profiler it identifies the LCD with the correct resolution. If there is something wrong with the LCD, or with the LVDS for that matter I don't think that the gfx card would identify the LCD panel. The thing is that, there is no output coming from the gfx to the LCD panel. Would that be a connector issue?

I don't think that the LOBO has some issues since when the cracked screen is connected it would output the video to the screen.

 

[Nameci]

I just wanted to bump this thread and ask for opinions before I would spend to buy a replacement logic board. Is it the way to go?

 

[666sheep]

I'd triple check all cables and connectors before that.

 

[Nameci]

I'd triple check all cables and connectors before that.

Yahoo! Fixed it, finally.

This is what i did;

1. I have disconnected the LVDS cable to check condition of the screen without the video signal. It showed a white screen with no dead pixel and backlight on. The video output is all sent to the external monitor via DVI. That is when I concluded that there is no problem with the screen, there is just no video signal sent to the LCD screen.

2. I then inspected the header on the Logic Board and I deem it to be okay and everything is normal.

3. Next thing is I have scratched the ends and pins of the LVDS connector that mates with the headers on the Logic Board, maybe just maybe, I suspect that there are contaminants that prevented contact on the mating parts.

4. Removed the outer RAM and let the inner remain on the Logic Board.

5. Booted in, and lo and behold, boot screen with apple logo appeared.

6. Shut the PB down and reinstalled RAM, reboot and all is working as it is.

As a matter of fact this is posted using my PB G4 Hires 1.67GHz with 2GB RAM.

Thanks 666Sheep for the advises, PPC ain't dead yet.

 

[WF19]

Hello. Could you help me please? I have the same problem with my powerbook, but I really don't understant what did you mean when said "4. Removed the outer RAM and let the inner remain on the Logic Board." Maybe just because english is not my native language) I dont understand *what is the outer RAM and the inner RAM) I've two RAM modules and what I should do with them? Thanx for any help)