cf28 backlight function

backlight stopped working on my cf28s tried another fully working screen on it still no backilight is the re a possible software conflicy or something more serious ???

anybody at my wits end with it


Rehgards Alex

 

It could be your inverter... Or did you change the inverter also?

 

inverter was my first thought but changed the whole top section for a working one just to make sure and still no joy ??? anybody

 

is it JUST the backlight? in other words, if you hold it at the right angle, you can see all the correct video display? If you have a working motherboard sending a signal to a working LCD with a bad backlight, you can angle it just right and be able to see (barely) the display.

 

Did you try to an external monitor?

 

What exactly where you doing when it quit working?

 

Where were you the night of the 15th?

 

working the night of the 15th sorry,,,,

was removing the lid running wireless ariels when it quit working,,

and yeah runs fine on external and also is just the backlight not working can see the panasonic logo on start up


Any ideas ????

 

Its your inverter board check it. it may be loose connection. Ok! if not, check the very tiny fuse on the motherboard before the connector on the lcd port, backlight supply area. You can be mistaken that is ceramic capacitor or diode. Also to remind you when you're doin on the potion area like on the lcd make sure that you have taken out the battery and Ac plug before you proceed to work it maybe the coz of all this trouble.

 

Could the backlight connector have come loose while you were running the ant.? Connector c-2 inside the LCD?

 

I killed one of mine by unplugging the LCD before the laptop turned completely off.
I was switching back and forth trying to see which one was brighter and powering off before each try but got a little impatient waiting and just unplugged thinking no big deal and it never worked again.
Both LCD’s still work and the mother board still works with an external monitor but will not power the LCD. Must be a fuse I’m guessing as I never looked into it any further just replaced the mother board.
This is why I ask what you where doing, because if you where unplugging the LCD without completely powering it down first then you just confirmed my belief this was what killed mine.

 

Ohm out the motherboard fuse....I am a gambling man, and I put my money on that....I bout 2 CF28's off ebay really cheap for "parts only" opened them up, threw in a new fuse on the motherboard, BAM!!!!! Working 100% like new, sold one, and still have the other one up and running all my radio programming software........bet it is the fuse.......

 

Ohlip... Do you have a reference number on the mobo for that fuse? Like F202 or something like that?

 

It is a white color with tag "SOC 63V, T 1A" same fuse used on Backlight inverter board. Do you know that the inverter board of ARMADA M300 can be use on cf-28? that right! but you have to retrofit its input connector. The inverter board of cf-28 is hard to find and it is an alternative one( for your information guys out there)

 

I still don't see it. Does someone have a picture?

 

Ok! here where it is located on mbo. you know the connector of cmos battery, followed by mic connector and another connector in front of it there is small white tiny little brick and thats it! a fuse on mbo. when you flip it upside down that is a part of circuit for backlight voltage supply to the inverter.

 

Does Radio Shack have these. (Yeah... Dumb question... I know...) They don't come up on Google. Gee... I guess a nice piece of copper wire would do!

 

radio shack! I don't think so! at one point that i don't have any source i just place a small resistor from dead mbo. the green color flat one with a rectangular shape and it works prfectly or if you have dead inverter boards even from other notebook you can harvest their fuses and use it. they are almost the same value. I guess!

 

Have you tried Digi-key???
http://www.digikey.com/
I know the only problem is a minimum 25$ order... but if you need alotta stuff...

 

I just ordered a bunch of ribbon cables from them. They were VERY helpful. It looks like they don't stock them.

 

I R&R'd the LCD cable on a CF27 while turned off but plugged in. Imagine my surprise when I got a SPARK at the motherboard connector! The ribbon connector had a burn mark on it! i thought for sure I broke something. lucky for me though, it all was OK. I now remove all sources of potential energy and perform a full lockout before messing around inside any toughbook

 

I think I just ran into the blown fuse problem. I've got two screens, at least ONE of which I had previously tested out as good, but when plugged into a random CF28 motherboard I pulled off the shelf, they both came up with no backlight. After much bewilderment, I opened up another 28 with a known-good display. Both light up! It has to be something on the motherboard's end. I will look around for the fuse and see if it needs jumping.. oops, i mean replacing

 

Gravitar
Please let us know what you find.
This is where I left off.
I think it is fuse #3 or #6 that protects the LCD but I can only find fuse #3 and it test good on mine.
This is the PDF I used to help me find the fuses but it’s a bit like where’s Waldo.

Good luck.
Jim

 

Check the F4.

 

wow, lots of fuses on these motherboards

 

What Ohlip said check F-4, its bad on mine.
Checked it before and I thought it was good but it must have been the beer talking.
Rechecked after Ohlip’s suggestion without a beer in one hand and the multimeter in the other and F-4 was no-good, Thanks Ohlip.
Now I just need to replace “jump” it and see if my LCD will light up.

 

Okay... Dumb question time again...

What stops us from soldering in a 1 Amp, 63 Volt bus fuse in place of the little tiny fuse? There is plenty of space in there for it... Plus it would be easier to change if it ever happened again!

Word of the day is !@#*%!.... I just blew the same fuse you guys are talking about when I was swapping around my monitors trying to find a good one to work on my laptop. I must have unplugged it while it was off but plugged in! The power cord was out but the battery was still in. Is there a high cap in there somewhere that stores a charge? How long should you wait before you switch?

I have a spare motherboard and am harvesting the fuse off of it. If I run into this again I am going to try the bus fuse route.

 

!@#*%!.... How many times are you planning on blowing the same fuse?
If it where me I would just jump it and stop plugging and unplugging the monitor with power applied.:wink:
If this idea doesn’t work or you want to protect your test board that you will be using for testing deferent monitors then yes I would just bring some new leads out to a glass fuse that is easy and quick to replace.

Jim

 

Another 800 MHz mobo saved by the F4 jumper trick! I wonder where the corresponding fuse is on a 600. I checked all the fuses in the same general location but they all ohm'd out good.

Now my problem is how to get this 800 mobo (that must have been originally attached to a 13" screen) to work right with the 12" screens I have around here. What it's doing is, you know how when it boots up, it starts the image at a location farther in than 0,0? Well it looks like it's picking the same starting coordinates on the 12" screen so I'm losing a lot of picture. I wonder if it would be ok once I get into windows and can set the screen resolution higher

 

What is the "jumper trick"? Just jumping the monitor fuse? I saw ohlip mention checking F4 but that was it.

When visiting my Mom over X-Mas I raided my Dad's old shop and picked out all the 1A buss fuses...

 

Yeah, I bridged across the fuse with one of the leads from an old capacitor I had handy. I don't have any SMD fuses handy (did your dad?) and would have not really wanted to try replacing it, anyway!

 

They are actually very easy to replace... As long as you have one. Nope... No SMD stuff in my Dad's shop. Just old Buss fuses which will work like a charm. I don't think I would want to hard wire it... The fuse is there for a reason and the buss fuses would be even easier to solder in. And there is plenty of space for them.

 

i have a quick question
is the fuse solder in or can i use tweezers and remove it thxxx

 

Its soldered in and you need a tweezer for sure.

 

if i'm right the inverter board is part of the screen. also i have a cf-28 the the display is very very dim but a external moniter works on it ..thxxx

 

1.0:Its part but it is separated inside the panel, try open up the screen, you need to unscreww first the hinges cover and pop it out. 2.0:Its your backlight bulb need to be replace, but its cheap around 8 bucks.

 

Make sure all power sources are disconnected before you do anything though. If any power is attached (including battery) when you plug stuff in again, you could easily blow the backlight fuse on the mainboard they were talking about (assuming you haven't blown it already).

 

why not just piggyback another one on top of it, instead of trying to remove it from the board

 

Grav is right - you try and remove that fuse from the MB, you are as likely to delaminate the trace as remove the fuse. Just solder a length of thin single-strand wire to each end of the fuse & use that to bridge out to a GMA glass fuse, or if you have a SMD fuse just lay it on top of the old one & solder it down.

mnem
Why does everybody keep pushing the HARD button?

 

Well... I was having problems with an illuminated keyboard. It turns out the keyboard pc board under the plate on the bottom (Held on by 4 screws) also has one of the SOC 63V fuses too. But instead of 1A it is a 500Ma version. Now I can finally fix this keyboard that has been plaguing me!

 

back to the topic in hand has anyone found a source for the original fuse aprt from 600mhz boards

 

Yes... Substitute a BUS fuse! It does the EXACT same thing and there is plenty of room to install it! They work like a charm! No need for micro soldering or buying a $7.93 fuse when a .50 cent BUS fuse will work like a charm. Buy one that has 1A - 125V... It does the same job and works just as well!

And... They are available at Radio Shack! (The ones sold at auto supply stores might work but they may have 12V - 32V on the band and may not work correctly.)

I haven't been able to find a source for the original fuse.