CurtPalme.com Home Theater Forum

**Curt Palme**

I have a possible issue in the field with a 9500 Ultra that burnt a line into all three tubes, indicating some sort of V failure. The set is working fine right now, so it's not a permanent component failure, but it could be something intermittent. I'm having the customer check to see if it could be a glitch in the setup, so I'm not postive it's phosphor burn, but for fun I tried something with my test 8500 chassis here to see if indeed the Marquee could burn the tubes.

I UNPLUGGED A V YOKE CONNECTOR WITH THE SET ON! Shocked

Do you know how hard that is to do, even when doing it on a set with text burn on the tubes? Really damn hard, when you spend all your time PREVENTING tube damage.. Thumbs Up

What I found is that despite unplugging and plugging in the red and green V yoke connectors, and the set showing a normal image, I could NOT get any of the three tubes to burn the phosphor, even after unplugging the V yokes about 20 times. I then went further and unplugged the V board connector from the motherboard to see if I could get a tube to burn. Nope, couldn't even get a line on the tube as the V collapsed. I did that 5 times.

Then (yes, I'm a sadistic bastard!), I pulled the CLM to see if the V would collapse. 3X I did that, and not even a spot, the set just shut down.

So the question for all of you Marquee owners, is have you ever had or seen a Marquee that had a tube with a line burnt into the tube face? (spot burn doesn't count, a disconnected G2 lead will do that). I want to know about a V deflection failure burnt into a tube face.

Thanks!

**Curt Palme** · Posted: Tue Oct 23, 2007 2:49 am Post subject:

OK, never mind, the customer says now that he can't see a line burnt into the tubes. Whew! Sounds like he needs a new setup...

So.. just FYI, it's really hard if not impossible to burn a line into a Marquee, even if you try.

WARNING: Do not try this at home, the above post was made by trained profeshunals!

Joust · Posted: Tue Oct 23, 2007 3:00 am Post subject:

good to know.

**AnalogRocks** · Posted: Tue Oct 23, 2007 5:09 am Post subject:

Wow did you do the HV dance Curt??

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I will tell you EXACTLY how to get a spot burn on a CRT installed in a Marquee.

Unplug the G2 line from the neck card.

Allow the tube to runaway and go to max brightness. While it's at max brightness and BEFORE the current limiter
circuit shuts down the HV, turn the PJ off with the wired remote control.

Bam. Spot burn. Oops. Shocked

I know...because it happened to me. And thus I wasted my first good tube. It was a pristine, I mean PRISTINE, GREEN
P16LNQ, if I remember correctly.

However, as long as the G2 line is connected, and the spot kill/current limiter circuit is working correctly, it is indeed
virtually impossible to cause a line or spot burn on a Marquee.

But I can't think of a single failure that would allow all THREE tubes to spot burn at once. You'd have to unplug all three
G2 lines or have three separate neck cards with a spot kill circuit failure at once.

Or...just maybe...check the supply voltage rail that feeds the spot kill circuit. If that rail were to fail, it MIGHT allow
such a thing to happen.

CJ

**Curt Palme** · Posted: Tue Oct 23, 2007 2:39 pm Post subject:

Been there, done that. Turns out the problem was banding, not a burn. The customer really had me going for about an hour though.. Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Ah, a happy ending. Good.

CJ