CurtPalme.com Home Theater Forum

RVonse · Joined: 09 Mar 2006 Posts: 3152

Specifically what I am talking about is the loud high voltage snap followed by no video for about 1 second. We've all experienced this at one time or another but lately it seems more frequent for me and I think it may very well have to do with a different red crt installed 6 months ago. Or perhaps the new quad I put in about the same time? I just don't know. But I do know that the red crt (panasonic 9"er) came from a guy in Florida who had it stored idle for a number of years.

For a while I even thought I was having a video fault on one of my cards. The picture would fade out but I knew there was still high voltage because the crts were still lit if you looked directly into them. Until then one day a large amount of popping took place which seemed to correct the video dropout issues I thought I had. On some occasions, I see a flash of all red raster but most of the time it is just one single pop, blackness, and then video coming faithfully back. Scares the crap out of me.

So my question is, is this something that some crt's tubes can do more than others and could it be high voltage arcing in the guns?

It hasn't really been a huge problem but I can't help but think there might be something to do in order to prevent a disaster in the making.

Mark_A_W · Posted: Tue Jul 14, 2009 11:00 pm Post subject:

When you crack open a tube and see inside (they are basically empty apart from the electron gun assembly), you really do have to wonder.

My new P16 tubes did a couple of little pops, nothing major.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Its small pieces or dirt or contamination or phosphor that finds its way into the tube during the phosphor application phase. Tubes should be stored face down so none of those loose particles find their way to the Cathode,G2 or G1 grids. The pops are those contaminants getting fried by one of those components, some times tapping the tube neck after installation will shake these parts free and/or burn them off.

Athanasios

Mark_A_W · Posted: Tue Jul 14, 2009 11:49 pm Post subject:

What I'm trying to say, is when you crack open a tube, you have to wonder where these mystery loose particles come from..

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

You guys are forgetting the fact that this could be caused by a HV arc anywhere in the HV path, not just in a tube. I didnt see where he posted that he saw the arc in the tube. So he would have to look for the arc to see where his problem is. It is not just inherent to a tube, even tho it could be. Smile

Rdean · Joined: 13 Oct 2006 Posts: 258

Have you had the covers off and lights out and tried to see where arcing may occur? I had a similar problem. A pop followed by video going black then slowly coming back over a second or so.

Mine was arcing from the HV boot to the tabs on the deflection yoke. To fix I replaced the HV leads as in

http://www.curtpalme.com/HV_Lead_Removal.shtm

Age causes the boot's rubber to dry out and small cracks allow paths for the arcing.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Age and ozone. Have you ever tried to stretch on old rubber band and have it break. Ozone breaks down the chemical bonds in rubber.

http://scifun.chem.wisc.edu/CHEMWEEK/Ozone/ozone.html

Older Infinity speaker surrounds come to mind.....

Rolling Eyes

Cousin.It · Joined: 09 Feb 2007 Posts: 41 Location: Hurst, TX

I had a projector a while back that sat for a while and when I got around to turning it on again it had a bunch of crackling pops it kept doing. I tracked it down to tiny spiders and little spider web strands in the tube bell area. I just cleaned that area out and fixed it.

Mark

dturco · Posted: Fri Jul 17, 2009 3:24 pm Post subject:

What causes crt's to poop?= GOZER sauce Laughing

ecrabb · Posted: Fri Jul 17, 2009 4:15 pm Post subject:

DAMMIT! You beat me to it! I've been meaning to pop into this thread for the last two days and make some reference to never hearing or seeing my CRTs "poop" a single time. What does CRT poop smell like, anyway? Fried electronics?

SC

**AnalogRocks** · Posted: Fri Jul 17, 2009 5:20 pm Post subject:

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia