• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Is there a procedure or general guide for replacing the CCFL tubes in backlights

Status
Not open for further replies.

jpoopdog

Member
I have a wacom cintique 24HD, an expensive monitor i got fairly cheap in a scam of sorts, i was sold a dying monitor, the tubes are on their last legs, they only really reared their weakness once it got really cold, which took a while since we had unseasonably warm weather from since i bought the monitor over a year ago until now. I cant send it in for repair because im poor and i have no warrantee, the thing weighs a ton, and i have to cover shipping, with no guarantee itle be fixed.

Anyway, monitor works fine (displays a picture) but the backlight, which operates almost completely independantly, often fails to start and leaks HV from the cables, indicating that the tubes are bad, i tried replacing the capacitors but it didnt work, although oddly heating the capacitors up sometimes helped it start i think this was just coincidence, or, causing leakage that helped somehow.

Ive opened the monitor several times. everything is attached to an aluminium plate which sits on the backlight i asume, which appears to have its edges all wrapped in something like packaging tape. There are 6 inverters powering 6 pairs of leads, i asume that there are 6 lights.

what do i do? is there a proper procedure for replacing the tubes? like, in general for backlights?
Ive been told i should be able to just yank it out and stick in a new one that its that simple. Is it?

if it comes to the point i cant identify the tubes ill just replace them with LEDs, when one tube fails it doesnt cause uneven lighting. The driver just takes PWM and has a single feedback port which outputs 5v as long as the inverters are running to indicate its ok.

So, how should i go about taking apart the backlight and accessing the tubes? This is actually a common problem, this model of monitor failing in this way after a while.
I forgot to mention that i need to do this non-destructively, ive spoken to wacom, they said as long as i dont cause damage suggesting i caused the failure, they will repair it. I want to keep that option open which is why im not just arbitrarily cutting and prying things apart. Ill post some photos if neccesary.
 

Tony Stewart

Well-Known Member
Most Helpful Member
I have replaced the CCFL's in a laptop once. After careful removal, I measured the length and diameter and ordered from Digikey and it worked. The ends were just a filament wire to be soldered. The clue they were bad was a warmer white in the electrode ends diffused on the edge lit display. Then they shutoff from over current sensed by the thin HV driver board and would work for a week or so when cool and shutoff once warm.

Removal procedure was difficult just because of space constraints in the laptop lid and fingers less nimble than they used to be and difficult laptop assembly methods, but were housed in a tiny U shaped reflector and had tiny O-rings to be re-used centered in the edge reflector assembly.

After a while my connections failed inside and I ran out of patience to disassemble and reassemble, so I set it for my wife as her personal web/email browser with a 25" external 1080p monitor and wireless USB dongle keyboard and got another 5 yrs life out of of it keeping it an inch off the floor for air circulation.

Good luck.
 

dr pepper

Well-Known Member
Most Helpful Member
Have a search around ebay, you can get generic ccfl driver boards, you might be able to get tubes the correct length.
If the ccfl driver doesnt communicate with the rest of the board you might be able to replace all of the illumination parts.
Might also be worth a scrounging session at your local computer rapir place, or e waste recyclers and see if you can get some more tubes that fit.
Changing them is incredibly fiddly, the only procedure I know is to struggle and swear a lot.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top