Static/light popping sound & video instability

[Nipedley]

Hey guys, some of you probably remember me and the monitor from hell!!

For those of you that don't, this monitor has had every transistor replaced, every capacitor except the ones in the flyback area, and every IC on the board. The only thing that's left is the aforementioned caps, and the flyback.

The monitor worked great for a while and I solved the original problem, but its slowly been developing a loud popping/staticy sound and it's now affected the screen - the focus seems to change wildly, and the screen will sort of shrink inside and then return to normal and then shrink again everytime I hear this sound (which is continuous)

Can anyone confirm my suspicion of a dud flyback? Cause I've replaced everything else!

NOTE: Hantarex MTC9000

[Level42]

Does the sound come from the HV cup area ? What kind of plastic is it ? See-through ? If so, this has become too stiff over time to work well. It's a problem I have with two Hantarex 900's. Replacing them is the only real solution.

It could also be dirt around the HV cup area that makes the area conduct a bit to the dag.

Check this out:

http://www.jammaplus.co.uk/forum/forum_posts.asp?TID=10838&PN=1

[MonMotha]

A common cause of this is a short in the tube combined with a bum flyback.  If you know somebody with a tester/rejuvinator, they can check the tube for a short (and potentially clear it, if there is one).  Also replace the flyback if that's the cause.  May be just the flyback bad, too.

May also just be that your anode cap is loose, so check that.  Make sure there's no moisture in the area, too.  It's starting to get warmer/damper out, so that may be the cause.

[qrz]

don't overlook a possible faulty crt socket.

spark gaps can become clogged with debris, pins can corrode, etc...
corrosion can sometimes conduct 


qrz

[Nipedley]

Thanks for the replies, guys.. The anode caps black, and seems in pretty good condition last time I saw it.

What would you recommend I clean around the anode area with? As I seem to remember reading dag being soluble and that would be the last thing I want. I'll check the pins over as well however I'm fairly sure that's all good.. Which would mean either flyback or a short. I so, so hope it isn't a short. I doubt there's a rejuvinator within 100 miles of me either..

I'll probably replace the flyback just for the hell of it and see if that does the trick. If not, I'm shopping for a 20" crt? Not going to be easy nowadays

[SirPeale]

Why didn't you replace the caps around the flyback?  Those are pretty important.

Turn off the lights, turn on the monitor and look for arcing.

[Nipedley]

The caps around the flyback are surrounded by a metal shield which I couldn't seem to remove without also removing the flyback. When I get some more cash in I'm going to replace the flyback & all the caps around it, at least then I know my chassis is 100%..

Tempted to try and source a rejuvinator but i suspect it will be very difficult down in cornwall.

It may also be worth noting that the chassis has had the flyback replaced before I got it, shoddily, and the guy had to bridge a trace that he cut in the process. It's always worked fine until now however so I'm not sure how suspect that is?