Hi I have a 5 year old Sony GDM-FW900 CRT ,for the past month or so during warm up the monitor will emit a semi loud "snap" sound ,it always happens about 5 minutes after being powered on and then randomly after that but it usually only occurs during the first 20 minutes (maybe 3 or 4 times) then its fine the rest of the day, the picture quality is unaffected during these sounds and overall it still looks very good I was just curious if this is a sign of things to come or if anyone has any ideas on what it might be, Thanks.

I have a webcam server monitor running every night that has done that since i got it. No idea of the model but it does the same thing. It was found in CleanUp week in May on the kerbside and seemed ideal for the purpose.
After 5 mins it may momentarily fizzle the screen slightly as it snaps audibly.

Several months on and lots of use later, it does it less often and is perfectly fine, display wise!

I think the sound is dust build up related (5 years you say on yours too). I can envisage that the snap could be superhot dust on the back of the neck board, temporarily messing with the circuits when heated up after the 5 mins?

But suffice to say, if dust is minimal it could well lessen and return to full functionality.
If it was stored or moved then that could be why it now does it.
A more technically experienced member here will hopefully divulge the actual cause though

A while back, I had a similar problem, and it turned out to be the flyback. It is an easy fix on these monitors, as long as you have basic knowledge of electronics, soldering skills and access to the maintenance manual.

The part# is 145334811, FBT ASSY (NX-4504//J1D4), and it cost $98.18.

Hope this helps...

Sincerely,

Luis A. Grunauer, Jr.