[wellylug] Faulty Monitor

Tony Wills ajwills at paradise.net.nz
Tue Aug 24 08:58:55 NZST 2004


At 07:33 24/08/04 +1200, Jethro wrote:
>A high pitched pure note.

Yep the flyback transformer then.

>I wouldn't try fixing it myself. Don't moniters store power in their
>circuit, like power supplies?

The usual worry is the screen cathode ray tube (crt) which has a connection 
that runs at thirty odd thousand volts, it can store a charge for quite a 
while.


At 07:46 24/08/04 +1200, Eugene van Wyk wrote:
>Better to have it seen to earlier rather than later.
>The whine is most likely from the line transformer, which is going
>faulty internally, and if it goes, can do quite a bit of secondary
>damage.

Yes the flyback or line-output transformer (lopty), maybe an internal 
fault, but often just a physical mounting problem allowing it to vibrate.

>I've also had cases of a whine being caused by damp dusty buildup inside
>the monitor providing an alternate current path, in one case
>particularly by cat hairs and dust getting nice and damp in a salty sea
>air environment.  In this case the board damage was too extensive too
>fix economically.

In that case you're hearing the wheezing sound of an electrical discharge 
(arcing) from that high voltage where maybe the insulation is cracked or 
there is a low grade short circuit as you describe.  You'd probably also 
detect an ozone smell.


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