DV9000 - dim LCD - not inverter or ccfl

[Lumberjack777]

OK, I've had a few of these with the no graphics issue and it was always a reflow or reball of the GPU.
Basically, I can barely see the "HP Invent" logo when I power it up. So I tried a known good LCD screen and it was also dim. No Backlight. I tried another known good one and it was dim also. So I'm absolutely sure it's a motherboard problem.
I do notice something interesting. The backlight will flash for an instant when the AC adapter is plugged in. It hasn't even been turned on yet and the backlight flashes. I believe that is some short of short since the power button hasn't even been pressed yet.
Any ideas?

[heavymachines]

Re: DV9000 - dim LCD - not inverter or ccfl

this is a new one....probably will need schematic for this model..., see if there is anything obvious on motherboard....

[ben7]

Re: DV9000 - dim LCD - not inverter or ccfl

Maybe low supply voltage to the inverter?

[Lumberjack777]

Re: DV9000 - dim LCD - not inverter or ccfl

You both were right. Thank you. After examining the motherboard I finally took a jeweler's loupe and looked inside that thin black LCD connector on the motherboard. On the very end I could see some melted plastic inside that would have blocked the last few thin metal connections. Apparently what had happened was somebody plugged in the LCD and didn't snap it all the way in, and it arced and shorted the inverter circuit.
I do have a harvest motherboard. But replacing that connector requires some micro-soldering. There must be at least 28 legs within 3/4 of an inch. Wish me luck, and thanks for the input. ~L-J-7~

[ben7]

Re: DV9000 - dim LCD - not inverter or ccfl

You both were right. Thank you. After examining the motherboard I finally took a jeweler's loupe and looked inside that thin black LCD connector on the motherboard. On the very end I could see some melted plastic inside that would have blocked the last few thin metal connections. Apparently what had happened was somebody plugged in the LCD and didn't snap it all the way in, and it arced and shorted the inverter circuit.
I do have a harvest motherboard. But replacing that connector requires some micro-soldering. There must be at least 28 legs within 3/4 of an inch. Wish me luck, and thanks for the input. ~L-J-7~

If it shorted the inverter then it would have not worked, and possibly been damaged. I think it was just a bad connection (high resistance) which dissipated enough power to get hot. (the high resistance also limited power to the inverter, so it got dim)

I'm not an expert on the tools side of SMD soldering, so I can't help you there

But if you want to replace this, we could try to find a replacement online. I think it might be tricky, as this could be a custom connector. It would be helpful to have a very good macro photo of it, and it's dimensions (lay a metric measuring stick next to it for some size comparison).

You could (if you had the tools) get a donor board, which could have something else on it that is broken, and use it for parts. You would have to de-solder the connector from the donor board, and solder it onto the board you are working on right now.

-Ben

[opamp]

Re: DV9000 - dim LCD - not inverter or ccfl

You both were right. Thank you. After examining the motherboard I finally took a jeweler's loupe and looked inside that thin black LCD connector on the motherboard. On the very end I could see some melted plastic inside that would have blocked the last few thin metal connections. Apparently what had happened was somebody plugged in the LCD and didn't snap it all the way in, and it arced and shorted the inverter circuit.
I do have a harvest motherboard. But replacing that connector requires some micro-soldering. There must be at least 28 legs within 3/4 of an inch. Wish me luck, and thanks for the input. ~L-J-7~

Very simple to do with a hot air rework station with, a 5mm tip and some solder paste. If you only have a soldering iron you will need chipquick to remove the connectors safely.

[Lumberjack777]

Re: DV9000 - dim LCD - not inverter or ccfl

OK Ben: I have a donor board and have removed the lcd connector from the current board. Thanks for your help.

opamp: I have never used the solder paste before. But I checked it out, and it looks like the ticket alright. I ordered some Chipquik solder paste from Newegg.

I'll report back when the solder paste arrives and I give it a go. Thanks for your advice! ~L-J-7~

[ben7]

Re: DV9000 - dim LCD - not inverter or ccfl

OK Ben: I have a donor board and have removed the lcd connector from the current board. Thanks for your help.

opamp: I have never used the solder paste before. But I checked it out, and it looks like the ticket alright. I ordered some Chipquik solder paste from Newegg.

I'll report back when the solder paste arrives and I give it a go. Thanks for your advice! ~L-J-7~

Best of luck!

[Lumberjack777]

Re: DV9000 - dim LCD - not inverter or ccfl

Very simple to do with a hot air rework station with, a 5mm tip and some solder paste. If you only have a soldering iron you will need chipquick to remove the connectors safely.

OK, I do have a hot air rework station and the 5mm tip. The solder paste also arrived from Digikey. I have never used this method before so I'm a little unsure about the temperatures needed.

1. What temperature should I set the hot air at to safely remove the connector from the donor board? Most likely that solder is lead free.

2. Once I apply the solder paste, what temp should I use to solder it back into place with the hot air?

Or anybody that knows.

Thanks. ~L-J-7~

[opamp]

Re: DV9000 - dim LCD - not inverter or ccfl

It's a connector it won't get heat shock. Use your soldering iron for the outer welds then concentrate on the pins with the hot air.