cf-28 screen noise on boot, inverter?

Hi, I get a whine from my CF-28 screen when I boot it, it goes away by the time the desktop is up.

Is this a concern?

I have been told I should replace the inverter, do you think this is correct?

If so do you know where I can get one?

Bill

 

Bill -

First off - Welcome to the forum!

This question really belongs in the general forum, not the BST.

MODS - can we please move this thread where it belongs? Thanks!

While it is possible that the inverter is failing, what is more likely is that you have an LCD with a lot of hours on it and the CCFL tubes are getting weak. When they are cold, they require quite a bit more current to operate; this loading of the inverter is what makes it whine. As the tubes get older, this cold current draw gets higher and higher, until eventually it either drives the inverter into shutdown from current overload or the tube simply fails to arc.

A couple things to look for as evidence of a failing CCFL:

The next time you've left your laptop off for a day, take it into a dark room and INTO BIOS SETUP and keep it there, observing the screen over time. If it is markedly darker at first then brightens up considerably as it warms up, then you probably have weak or failing CCFL(s).

If it starts up with a pinkish or reddish tint noticeable in white areas, which goes away after it warms up, this too is a sign of one or more (depending on model) failing CCFLs. If it stays pinkish or reddish, this is evidence of a leaky tube that has been contaminated with air and is a definite sign of impending failure.

Actually, the symptom of starting out pinkish or reddish is usually an early sign of air contamination as well, but sometimes it is a result of the normal burn of the electrodes inside the tube; if that burn releases some impurities in the metal of the electrode it can cause this behavior as those impurities oxidize.

In this scenario you may still see quite a bit of useful life out of the CCFL, years in some cases.

The CCFL CAN BE REPLACED; but it is NOT a project for the uninitiated. I would call this an EXPERIENCED (Don't try this unless you ARE Dilbert ) level repair; fragile LCD panel (Layers of THIN glass) disassembly, soldering and high voltage repair safety precautions are involved.

If you don't ALREADY KNOW what I'm talking about PRECISELY, then DO NOT attempt to replace your CCFL.

Investigate your LCD as described; I'll almost bet that as the screen brightens, the whine goes away.

mnem
ElectroZap. Squared.

 

Hi, thanks for the reply, I bought the cf-28 on ebay I will try to return it, but first I will try the bios test.

Looking at the forum you seem to have many similar issues, I will go away as you wish, but this seems to be more than just me.

 

Bill -

I didn't mean that you should go away; only that you had posted in the Panasonic Buy/Sell/Trade forum, and this technical question should be posted in the general forum. This means that many people who might have some valuable input on your question won't see it, since they may only look in on the B/S/T very rarely if ever.

I'll see if I can get one of the mods to move it for you; it's really no problem.

mnem
Lost. Unfound.