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01-04-2012 08:47 AM
Thanks for the information. I'll study the disassembly instructions and then decide whether to expend the effort & cost to tackle the problem. When I booted into the Bios screen (as you suggested) I didn't get a normal display but when I took a flashlight and held it at an angle, I could see a very faint image on the screen.
Thanks again. You've given me enough information to pursue the issue further.
01-19-2012 07:57 PM
I pretty much had the same setup and problem. It happened 4 days after my extended warrantee ended.. after reading numerous other entries, I decided to change the back light driver. This did not help, but was a cheaper item to try first. Then I bought a new display and that resolved the issue.. Total expense was around $200. Which was cheaper than getting a new computer. Especially one with all of the features this has. One other good thing is my old display had 5 dead pixels. I have not found any on this new one.
This is my 2nd week with no problems.. So I consider this resolved...
01-19-2012 09:41 PM - edited 01-19-2012 09:45 PM
I think my 2.5 yr old HDX 16t-1200 is suffering the black screen issue. I did the flash light test and I can the display content. So I think the video cable and the system itself works fine. I suspect the inverter is the culprit here.
When I used my part number (NK133AV) + S/N I got the return of 2 parts for the inverter and I am not sure which one I should pick. Hopefully someone has had experience with this.
488317-001 In stock
Display panel power inverter circuit
RoHS: Modified $56.81
496467-001 In stock
LCD panel power inverter circuit board
RoHS: Modified $42.28
If I click on the first one I see the list of part number where this part is used, but NK133AV is not one of them.
If I click on the second one (496467-001) I also get a list and NK133AV is one of them so I am thinking that the second part is the right one.
The first one does say circuit while the second one says circuit board. I assume they are the same.
Should I go ahead by ordering the second one?
Thanks in advance.
Edit: I did a searct for HDX16t-1200 inverter and I found this (significantly cheaper):
I wonder if they are the same thing?
01-19-2012 10:42 PM - edited 01-19-2012 10:45 PM
The difference between the two are is one is for a single lamp and the other is for a dual lamp arrangement.
From experience here on the forum, all have been with dual lamp arrangements in which case you need 496467-001.
However the only way of knowing for sure is to take the machine apart. The dual lamp screen will have 4 wires coming out of the bottom of the screen plugging into one end of the inverter while the single lamp will only have two wires.
These wires a totally separate from the video cable and are connected directly to the inverter.
The connection to the low voltage end of the inverter is integrated into the video cable itself.
So from your research, I would go with the dual lamp inverter.
When I am on my other computer it has some links to videos and you service manual on how to disassemble your machine. It's a big job, so be prepared.
01-20-2012 07:15 AM
Thanks! I will order the part and study the procedure before trying. Luckily this is not our only computer so I can take my time.
It does look like a big job but I have done similar type of DIY so hopefully I don't screw it up.
01-20-2012 07:37 AM - edited 01-20-2012 07:40 AM
Here's the HP Video Media Services Library.
and Maintenance and Service Guide.
When using the video library make sure to sign in to the forum before clicking on the link, give the pages time to load and if you have any problem getting to it, post again.
When you get there, there will be a list, don't jump to "Inverter". You have to start at the top of the list and work your way down _ you will see what I mean. Obviously you can skip the simple things like "How to remove the Battery"
Make sure you are statically discharged before opening up your machine, don't shuffle across a rug in some wool socks and zap your circuit board with the end of you finger.
You will be fine, there are allot of screws to keep track of so be warned. Work on it where it's quiet and some pet or little kid isn't going to get into it.
03-03-2012 08:21 PM
I finally got the part from HP and installed the inverter. I did have the dual lamp set up. Reinstalling the laptop was not hard but unfortunately it didn't fix the problem. The lamps still don't power up. When I shine a light on the display I can still see the content but they just don't light up.
I wonder if the inverter is bad or could it be other issues?
One question I have is that when I follow the video instruction, it said that the red/white inverter cable is in the outer connector while the blue/black one is for the inner connector. Is that correct? I seem to remember differently but I want to check before I take it apart again.
03-03-2012 09:42 PM
Well, in a few instances after I replaced the inverter, I could see the screen flash when I open the laptop after closing it (waking it from sleep.) The screen flashes for a fraction of a second and then goes back to black...
I think the lamps are okay. Could the inverter they sent me is bad?
03-03-2012 09:55 PM
It's unlikely the new inverter is bad, but rather the lamps are gone on the screen.
You can try changing the connections around, but it shouldn't make a difference. The red and white wires are for one lamp and the blue and black are for the other. With that said changing them around will not make a difference, but feel free to try it, you're not going to damage anything.
Note that you don't have to fully assemble the laptop to test things out each time.
Also when you boot up is the HP Logo light lit up on the back of the case, the same low voltage source that supplies that LED also supplies the voltage to the inverter ?
If you choose to test it partially disassembled be careful of the wires going to the lamps (red & white - blue & black) there is a fair amount of voltage there. None that's dangerous because there is virtually no amperage involved, but enough that you will feel it. Like if you grab a frayed spark plug wire in a car while the engine is running.
It is also possible that the video cable is not supplying voltage to the inverter, but unlikely, in your case if a new inverter does not cure you problem, the screen will have to be replaced.
Although the lamps can be replaced as separate units, the job is very tricky. The new lamps are extremely fragile and difficult to handle. Removing the old ones with out damaging the screen is possible, but quite difficult.
It is easier to replace the screen.
I have come across this sort of problem before, most times the inverter, the cable and the screen end up being replaced.