Problems? See this thread at archive.org.
Hello all,
First time poster...just found this forum this morning. I read most of the threads here and there is great information...by far the most informative forum I am a member of. When my CF-28 boots up the Panasonic logo comes on then quickly flickers and the screen dies. The computer boots up and is visible on a remote monitor. I checked all angles and cannot view anything on the laptop screen. The interesting thing is that when I got the computer it had Windows 2000 on it. It would not boot up and kept restarting, and was not visible on a remote screen. I installed XP and is now visible on the remote, but not the laptop display. Can someone point me in the right direction. Sorry for any redundancy and I look forward to learning alot more. It is a CF-28 800 MGZ PIII with 256 RAM and CD/DVD ROM. 13.3 touchscreen monitor.
Thanks again
Kevin
-
-
-
-
Grav -
One thing to consider when looking into a flickering screen to look for signs of arcing around the CCFL high voltage power leads & metal LCD frame. A smell of ozone when the unit has been running a while is a dead giveaway; though with the sealed LCD on these TBs, I dunno if enough would be able to escape for you to smell it.
I've had more than a few where I was able to fix this simply by applying heat shrink tubing to a lead that had gotten nicked by sharp metal or pinched.
Also look for evidence of arcing or burning around the transformer on the inverter; obviously, these issues usually require inverter replacement.
Remember that these units use a CCFL/mercury vapor lamp that operates at high frequency/high voltage. As those tubes age they require more current to operate, often eventually overloading the inverter (as with a number of Compaq & Gateway models you see inverters advertised & bid on heavily @ eBay) & damage the inverter. If you've ever seen a fluorescent lamp that flickered forever because of a bad bulb with a black end, then quit because it finally blew up the ballast, you have the exact same thing only shrunk down to fit inside your LCD.
If the display is dim to begin with AND flickering, I'd consider replacing the CCFL tube first (I know, not necessarily an easy project); it may very well be causing your inverter to go into shutdown because of excess current load. If you try a new inverter and your screen works but is still dim, I'd replace the CCFL to prevent having a $8-$16 tube ruin a $40-$80 inverter (Plus, you get a nice bright screen in the bargain).
I've never done one of these TB LCDs so I don't know how hard it is to replace the CCFL; because of varying designs some laptop models are merely a pain in the arse, while some are nearly impossible to do without damaging the LCD.
Be very careful as you'll be handling the raw LCD glass and several layers of refractive plastic. Try no to unstack the layers, as it almost guarantees getting dust between the layers, and look for the cleanest area with the least likelihood of airborne dust particles you can commandeer for the same reason.
You have to disassemble your LCD and remove the CCFL & reflector before you can order a replacement - there is no such thing as standard sizes. Remove the CCFL from the reflector carefully so as to not damage the rubber endcaps & the tiny clear o-ring spacers - you'll need these for the new tube if you can get them off in one piece. If the endcaps tear, you'll need to repair with clear silicone sealant (Let it cure fully before powering up) when you reassemble the tube or they'll leak high voltage and eventually arc out.
Use a caliper to measure diameter, you simply cannot measure these with any type of ruler. Most modern models use a 2.0mm diameter tube, but I've seen 1.3, 1.8 & 2.6 mm as well.
You can use a ruler to measure the tube length; you need to consider not only the length of the glass part, but also the length of the leads on the end. 6-8mm shorter on the glass part won't make any noticeable difference in the light diffusion, but 1mm too long (including the leads) and you'll break the tube installing it. New raw CCFL tubes have a lead approx 2-3mm long on each end; keep this in mind when calculating length.:GEEK:
As soon as you have your CCFL diamter x length calculated, write it down then place EVERYTHING inside a plastic bag and seal it shut. This helps keep dust from getting inside the layers while your LCD is disassembled waiting for your new tube to be delivered. I place the LCD face down on a piece of cardboard, then some paper, then all the loose bits & keep the screws & small bits in a ziplock baggie.
Oh and one last thing - DON'T EAT OR DRINK ANYTHING while you're working with these tubes;
just like a fluorescent bulb, they contain a small amount of mercury vapor & if they break it will get on your hands, even though you can't see it. 5 minutes later you're distracted and you reach for that last half of a sandwich & BAM! you're eating mercury like a carp from the shores of 3 Rivers Stadium.
Good luck,
mnem
"Mrs K, I'm afraid it's bad news. Your son was born with... THE KNACK."
"Isn't there anything we can do?"
"I'd say start with a socket set, and maybe a good multimeter..." -
I wonder if I can use the same excuse. I've just been getting fat from all the pizza and beer though, and the lack of excercise in the winter.
I do inhale alot of metal dust though (Iron and aluminum), so maybe I can just use that one for now
CF-28 screen flickers then dies
Discussion in 'Panasonic' started by bugly, Jan 14, 2008.
