CurtPalme.com Home Theater Forum

[deewaan1]

Hi all! My projector was faulting (LVPS fault light would click on and off) and would not power up. I trouble shot it and found that it would power up when I removed the focus board. I just replaced the shorted focus board with one I got from Curt (so it's good). So now with this new focus board in the projector powers up fine but the tubes won't come on. No crackle. Any idea what I might look at now? Thanks in advance!

[Tim in Phoenix]

Hello


Losing a focus board suggests a tube has arced high voltage from the tube glass to the focus yoke. Sometimes, a cracked chip can be seen on the failed focus board which may suggest which tube arced. Other yokes may also have been hit, so you could have a damaged horizontal board, vertical board, stig amp board or convergence board. Pop the front grill and see if any lvps diagnostic leds stay lit. They could help narrow down the failed board, or the lvps itself may have issues.


.

[draganm]

if it is indeed a HV arc or leak then it almost always blows one of the 2N7000 FET's on the HDM. HV leaks on the early marquee's are not uncommon, those early HV anode lead boots were sh*t.

[deewaan1]

[Nashou66]

The clicking isn't relays powering up the tubes, its selecting a the proper caps to switch into the circuit for the selected frequency that the CLM is sending it I do believe.
Disconnect the umbilical cord and G2 from each VNB one at a time, if one of the tubes has arced or it is internally shorted it could be causing the protection circuit on the VNB to send a signal to the HVPS to not come up. Aslo disconnect the HV lead from the tube your working on. Not sure if this will help any but its worth a try while waiting for a responce from curt. I had a faulty VNB and my LVPS light came up on the back lights too while i was recently moding a VNB for a sony tube. Pulling the Umbilical off let the HV come up for the other two tubes.

Athanasios

[deewaan1]

OK, 25 days without my home theatre! I've replaced the focus board like I said before, projector powers up but tubes don't. I replaced the HDM and no change. And I tried another LVPS and still no go. I also tried removing each high voltage line from each tube and powered it up one at a time and that had no effect. I guess I'll wait to hear from Curt as to which tube might have taken out the focus board. He mentioned to me that the grounds on one of the tubes might be a cause if one is not connected properly. I checked them and they are fine. Maybe it is the vert or conv board. Anyone else that may have any suggestions is more than welcome to throw them my way. Thanks.

[Nashou66]

did you try my suggestion in my last post? Removing the black umbilical cord from one VNB at a time? Also try removing the ribbon cable from the CVA board NOT the VDM,its the one on the left if your standing behind the PJ with the rear heat sink flipped down(floor mounted), unplug that from the mother board and see what happens. Try that first before moving to each VNB. Also when you power it up are there any lights lit up on the LVPS leds on the front of the PJ? And is it floor or ceiling mounted?

Athanasios

[deewaan1]

[Nashou66]

It could be , but also if the HDM board is not seated firmly in its slot it wont power up and you wont get an error. Are the covers in good shaper for the FCM and HDM, that is, is the foam on the inside of the cover there, soem ahve it some don'd. I put some of thet foam with one side adhesive on the insdide of the cover so it pushes and hlds the HDM in place while ceiling mounted.

Nashou

[deewaan1]

Yes the covers are in good shape and I replaced the foam tape in them awhile back. The boards are seated well in the slots. One thing I also did try today was to try powering up with the video input boards pulled and the projector didn't even try to power up the tubes.

[Nashou66]

[Ohmess]

I have a whole series of stuff I go through if I can't get my projector to fire up.

I reseat the HDM, try it, pull the HDM and reseat the daughter board, try it, reseat the LVPS, try it, reseat the HVPS, try it, reseat the HDM, retry, recheck all the connections on the CVA, VDM, try it, reseat the focus board, try it, reseat the HDM, try it. etc. etc. No matter what I try, I reseat the HDM about every third try. With a ceiling mounted projector, keeping the HDM seated is a problem.

I am not sure how much time you spend on checking connections and the like but I will spend 45 minutes or so, and then knock off for a day or two. After that, its another 45 to an hour.

Keep at it.

[Curt Palme]

A no pix condition on a MArquee most commonly is the HDM or the HVPS. Less common is a bad connection under the red tube where the HVPS connects to. A shorted/imploded tube. A shorted splitter that arcs the HV to ground. A bad VIM or a bad CLM. A bad neck board can do it too, I'd say that's also less common than the others listed above.

All of the above parts are best tested in a known working set, or subbed out with good known working parts rather than trying to troubleshoot without a s/manual, scope, meter and a whole lot of knowledge.

[Curt Palme]

A no pix condition on a MArquee most commonly is the HDM or the HVPS. Less common is a bad connection under the red tube where the HVPS connects to. A shorted/imploded tube. A shorted splitter that arcs the HV to ground. A bad VIM or a bad CLM. A bad neck board can do it too, I'd say that's also less common than the others listed above.

All of the above parts are best tested in a known working set, or subbed out with good known working parts rather than trying to troubleshoot without a s/manual, scope, meter and a whole lot of knowledge.

[deewaan1]

Thanks, I'll continue troubleshooting and let you know if I get it going. I guess I'll borrow a HVPS and then try other pieces (high voltage splitter, neck board etc.) if that doesn't solve it. Thanks again for all the help.

[Ohmess]

I'm also on my third HVPS in the five years I have had my Marquee.

Sometimes it helps to put your location in your posts. Then you can find out if there are local resources to help

[deewaan1]

Hey all! Just following up. It was the HVPS that was giving me the problem. I don't know if IT took out my focus board or visa versa. Anywho, problem solved. Thanks everyone for all the help. As soon as I get a new HVPS I can watch movies again. YAAAAAY!!

[draganm]

[Ohmess]

Yeah, I had the same thought.

The first one was an older 34 kv power supply, so I was not surprised (or particularly concerned) when that one went. After the second one went, I obtained from Curt an LVPS modified with a huge reostat to enable consistent filament voltage.

I measured it at 6.31 volts at P14 on the motherboard last month.

[draganm]

[Nashou66]