CF-30 LCD backlight only lights for 2 seconds

I am working on a Toughbook CF-30 model # CF-30KTPAX2M.
When you power it up, the Panasonic logo lights up for 2 seconds and then the backlight turns off. Also when Windows starts, the screen once again lights up for 2 seconds and again turns off. I can see faint images on the screen, but the backlight is off.
A connected external monitor works perfect all the time. When you press the Fn + F3 key to switch between internal and external displays, the internal LCD WILL light up for 2 seconds each time it calls for the internal display. If you press the keys repeatedly (very fast) the LCD will still light up for 2 seconds at each key press that call for the internal LCD display.
I ordered a new inverter board from Heartland and that made no difference, I still have the problem. I set the bios to the brightest display level and always on.
I read in other posts about an inverter fuse on the motherboard, but don't think that could be the problem as the LCD does light up, even though it is only 2 seconds.

Has anyone experienced this problem? Any solutions that I can try?
Any help will be much appreciated.

Thank You
Hansbo

 

I would first check the cables to the CCFL and be quiet to listen for any sparking sound between the cables and the chassis, while u start the laptop. The second check would be to connect another CCFL from an other display to verify, if the CCFL is bad or good.
And the last try would be to check the PWM-signal with an oscilloscope or multimeter, while u change the brightness via Fn-F1/F2.

 

Thanks for the tips. I replaced the LCD harness and that made no difference.
Next I found that the inverter has two sockets for the ccfl bulb. I connected one of the connectors to the ccfl plug on a used dell screen. To my surprise, BOTH backlights lit up, the one on the Dell screen and the CF-30 screen. So I disconnected the dell screen and did not reconnect the plug back to the CF-30 hoping that the CF-30 would still light up.... no go.

The CF-30 will not work unless I plug a good ccfl bulb into the upper socket of the CF-30 inverter and plug in the bulb from the CF-30 into the lower connector on the inverter.. The CF-30 screen will NOT light up if I reverse the upper and lower inverter connections to the dell lcd and CF-30 lcd.

Now, for my next question. Has anyone replaced the ccfl bulb in a CF-30. The wires from BOTH of the output plugs on the inverter go to the same place on the side of the LCD. Do the wires then go to bulbs on the top and bottom of the LCD internally? Is it possible to remove and replace the ccfl bulbs without destroying the LCD panel?

Thanks again onirakkiss for your help
Hansbo

 

How many hours does ur TB have?
I would exchange the defective bulb and probably the other one too, if u have more than 17000hours (2years working) on the TB. Quick google found this one: MS20275 . But I'm not sure, if they will fit exactly.
On the other hand; if u open everything in the display and u want to use ur TB the nxt 5y, why not move to LED? I have done this 2 times
And one hint: shoot pictures from every step while u disassemble the screen; for ur self and for the forum

 

I was waiting for the led solution to be mentioned by onarakkis. He's the pioneer that brazed this pathway. I await suggestions from another scary smart guru here..Driller

 

I'm with Driller, I want to see about the LED solution, while I don't have any backlight issues right now, I do have Toughbooks that have more than 17000 hours on them.

 

Had u found the threads about it?

Laptopdisplay auf LEDs umrüsten. - Mobil & Portabel - LedStyles.de

http://forum.notebookreview.com/panasonic/471036-changing-ccfl-led-display.html

But keep in mind, there are better solutions out there today find ur own

 

You don't need to design or create your own inverter for this mod. There is now a few seller on ebay, selling an led backlight couple with an inverter. But the question is! are you really want to do this without damaging the LCD? I am not questioning your abilty but it must be done with extra care. I am planning to do this on my personal M34 unit. But its a bit pricey and I don't have $ right now. It cost around 90+buck ( Led backlight and inverter).

ohlip

 

Was there a solution to the original post, I have a cf-30 with exactly the same problem. I like the led conversion but don't have the time to pursue it.

 

I am not 100% positive, but I think some CF 30's have 2 CCFL tubes inside the LCD. (most LCD's only have 1 tube)One of those CCFL tubes is bad. It's the same as one bulb burning out in a fluorescent light fixture with 2 bulbs. Neither bulb lights until you replace the bad tube.