CurtPalme.com Home Theater Forum

Jim Inkelaar · Joined: 17 May 2006 Posts: 8 Location: Kansas

Marquee 8500 was working just fine last time I used it, turned on last night and had a red and green line from the top to bottom of screen. Shut it down and when you look in the lenses at tube faces there is a line on the tube face from top to bottom like it was drawn with pencil on all three tubes. Any idea what caused this? I would hate to lose another set.

**AnalogRocks** · Posted: Sun Apr 21, 2013 4:41 am Post subject:

Ughhh Ohhhh that sounds like deflection burn. Do not power the set up. Curt will jump in here to help.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Certainly doesnt sound good, gonna be hard to wear level that if it is too...

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

It really sounds like horizontal deflection error, it seems you already loosed all three tubes. Remove the lenses and post a picture about the tubefaces. Pull out the P14 (the heater voltage) plug near to the blue tube, and try to power up the machine, and let's see if it throws an error (H defl) or shuts down itself.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Hello

I have some new 8500 tubes here for cheep, PM me if necessary. First you have to find out why Scan Fail didn't protect your existing tubes.

.

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

Yeah it sounds like Deflection Burn. Do as Gjaky says.

I might have a used set of tubes. there not great but better than spot burnt tubes.

I wonder why the Spot burn fail circuit didnt kick in? that is strange.

Nashou

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Guys

Possible VIM or Control Board issue, or the HVPS did not process the G2 slam off command. This problem is almost unheard of in Marquees.

.

**Curt Palme** · Posted: Sun Apr 21, 2013 1:06 pm Post subject:

At this point you've already lost the set. Sad

I have to say, this is the first time I've heard of deflection burn on a Marquee. I've pulled the H and V connectors off the boards while the set is live and have not had deflection burn occur. The others are right, there is a fault on a board that is not shutting the G2 voltage down when the set turns off. Install another set of tubes before you cure the initial problem, and you'll burn the new tubes.

Which tube face(s) have the pencil line on them? If one doesn't have it, then you don't need to replace that tube.

Best thing is to send in the HDM, the CLM and VIM to me or someone else for testing. Price out tubes in the meantime (I've also got brand new R and B for cheap, greens not so much, but have good used greens as well.

Or, replace the set with a refurbished tested one with new tubes for $1500 from me.

Also, if you want a slight upgrade, I do have this G70 here for $600, which almost guaranteed will be cheaper than the cost of tubes for yours and repairing whatever original issue you have:

https://www.curtpalme.com/forum_archived/viewtopic.php@t=33770.html

mp20748 · Posted: Sun Apr 21, 2013 1:23 pm Post subject:

Like Tim said, that is a very rare problem for a Marquee. I've had similar, but not to the point of tube damage.

Here's what you're going to have to do if you want to fix this problem.

The VIM has to be replaced...not repaired - do not repair.

The protect circuit should have prevented this from happening, because when the horizontal deflection collapsed. The HDM has a sense circuit that detects the deflection failing before complete collapse. This circuits sends signal to the CLM and VIM to blank out (turn off) the neck boards. This of course is done very very fast, and that is one of the best circuits features in a properly working Marquee, because it usually responds so fast, if you would even disconnect any of the deflection connectors, that circuit would shut down the neck boards and protect the tubes before complete collapse.

Here is the most common problem found with this circuit. usually, it is a single neck board that its shut down circuit fails or is failing. It still for the most part protect the tube from spot or line damage, but it will do so letting you see that its not doing its job so well. You would begin to notice this failure when the failing neck board would start to loose its muting ability. For instance, when you turn off the set, the failing neck board would show up on the screen, showing a flash or wide strike. It's letting you know it's time to replace that neck board.

When one or more neck boards show the same problem, they are fine, you then move to the VIM and CLM as Tim also indicated. And since the CLM also controls the G2, it too should be suspect, but the other circuits should have prevented complete tube failure.

What I've found to be a cause for this problem has been glycol contamination on the mother board and connector pins. The pins that carries the control signals for the boards mentioned operated at very high impedance, therefore any substance or change of resistance on any of those pins would (not could) effect the precious operation of those sensitive circuits.

If the tubes are damaged and you're looking at replacing them, start by solving the problem first with that same set of tubes still in the set. Start first by replacing the VIM, while at the same check for any appearance of a liquid or glycol leakage on or near any of the mother board sections of the projector. And also remove both LVPS and HVPS and inspect those connectors (on the supplies themselves and the area where they were removed).

**Curt Palme** · Posted: Sun Apr 21, 2013 1:33 pm Post subject:

Mike's answer was more concise than mine. If you do want to repair your set, feel free to send whatever boards you want to me for testing/repair/replacement. I do have a Marquee chassis with worn tubes to test potential bad boards like this in, it's already sacrificed its tubes for occasions like this.

mp20748 · Posted: Sun Apr 21, 2013 1:39 pm Post subject:

Curt, your answer was better still. It would be more cost and time effective to go with the G70.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Naaah...

Send it here and I'll fix the spot kill problem and install nine inch tubes Smile

You wanted a 9500 all along, right?

.

Phoenixed · Joined: 13 Oct 2011 Posts: 514 Location: The mitten

You can also pm me to if you need parts. I have an entire working 8500 not being used with under 500 hours on the tubes, but I say go with the G70.

Jim Inkelaar · Joined: 17 May 2006 Posts: 8 Location: Kansas

Hey THANKS guys for the replies. WOW you guys really got right on this one. Pretty much what I was afraid of. The good news (for me) at this point is I am a bit of a pack rat. I have a skelliton 8000, a complete 8500 (rough), 3 almost new tubes and a new blue tube. Thats the good news. Craig no glycol in these sets, what would it cost me to have you test the Boards. And do you think you would be able pin point the culprit. As for the offers on the G70 and the recon Marquee I'd be dreaming, one I'm too poor to pay attention, two the only thing I Know is Marquee and three what would I do with all the parts i've stashed. Thanks again guys if it was not for your help I would probably still be watching one of those little TV things instead of an 8' X 10' screen.

**Curt Palme** · Posted: Sun Apr 21, 2013 7:57 pm Post subject:

Jim, since you've already got nuked tubes in the set, and spare parts, why not keep the burned tubes in the set and use them to test the boards with? That's the simplest thing to do.

Most likely the tubes got nuked at shutdown. When you turn the set off, you should get NOTHING on the screen. A tube burn as you describe takes literally a millisecond to happen, so turn the set on and off a few times the way it is, and see if you can spot that H deflection collapse. It may be consistent, it may happen once every 100 times. If one of the existing tubes has no burn mark (the red may be clean I'm guessing), then pull the red CRT socket/video amp off the back of the tube, or take out the red HV lead going to the red tube out of the splitter. that will disable the red tube, and you'll save the phosphor. Heck, if you got really lucky, your green tube is intact, as they are the hardest to find in good shape.

If you see no burn line at shutdown, fire the set up, and start tapping boards and the chassis to see if you can get the set to collapse in the H deflection. Another possibility, though unliukely is that one of the white H yoke connectors is arcing. You should see burn marks on the white yoke connectors, or a charred connector.

If the burn shows at shutdown, start swapping the boards mentioned by various people above. Once you find it. THROW IT OUT so it doesn't make its way into anyone's set.