CurtPalme.com Home Theater Forum

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

Hey people!

Since I got a Marquee, it's been hell of a bumpy ride for me. This time it's not that minor though, the thing died. So, I've let it sit for a while. I accidentally broke 2 VNBs while doing a cleanup so I bought a set of them. (Not the broken spares, if you're reading Curt) I set it up, powered on but I got nothing. No diag leds nor even power led.

I went ahead and removed pretty much everything from the machine: VNBs, 2 ribbon cables on convergence and vertical board, Focus board, HDM, HVPS and event went ahead and checked that the fans run normally. I get a faint flash of LVPS diag light when turning on but there are no error lights lit in front of the LVPS.

Man I'm puzzled. Thanks for any assistance!

Cheers,
Eemil

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

You have a failed LVPS. It's far from a rare occurrence.

Curt has spares. Or if you have the time, the patience, and the soldering iron, you can recap the LVPS and
bring it back to life for about 3 hours of labor and some 50-odd caps to replace.

**Curt Palme** · Posted: Mon Sep 04, 2017 9:30 pm Post subject:

Pull the LVPS, and see if the standby fans spin with it sitting out of the set, as they should. That only means that the standby supply is working, there are many voltages and separate power supplies in that one box.

Feel free to open the supply and look for blown fuses or blown parts. Once in a while a capacitor will explode, take out a fuse, but everything else is OK. Other times some of the MOSFETs will short out, and smoke a bunch of parts, in which case it's cheaper to replace the supply.

I do have late model (2006) spare supplies here.

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

Alright thanks for the tips!

So it's safe to say the fault is in the LVPS and not in any connection inside the PJ? I checked the LVPS, gave it a little clean up with alcohol and checked for bad solder joints. Can't see any visible damage like burnt components or bulged caps. Also checked the fuses and they should be ok. I also think the standby works as the fans run and CLM gives me a standby light. Is there any way to diag it further?

One note tho! When the machine was working I remember hearing this high pitched whine coming from the LVPS when raising contrast somewhere over 50.

Thanks!
Eemil

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

Any Marquee with an LVPS that is more than 10 years old should be considered to have a weak power supply.

The electrolytic capacitors in it are drying out and not working efficiently and it is only a matter of time before one or more
voltage rails are weakened to the point where the projector will malfunction.

At this stage actual complete component failure is unlikely. You won't find exploded caps or leaked electrolyte on the PC boards
in the LVPS yet. But it can't deliver the current and voltage it's designed for anymore due to those caps.

Cleaning weak caps only makes them clean. It can't restore lost efficiency.

The high pitched whine from the LVPS at high contrast is merely more supportive evidence of weak/failed caps.

Get a replacement LVPS from Curt, swap it in, and watch movies.

I have seen this SO many times. A general failure to start and run without error lights on the diagnostic LED row on the CLM
is almost always an LVPS. It's more common by far than any other single cause.

Look in the cutout window in the front of the LVPS at the row of LEDs and you will see that the LEDs are indicators for the various
voltage rails, and they're labelled. Any of those LEDs that flicker or light up indicates a problem. A happy healthy LVPS shows no lights
when powered up.

**Curt Palme** · Posted: Tue Sep 05, 2017 1:51 pm Post subject:

Most likely it is the LVPS, but you can do one more test:

Remove all modules and disconnect all wiring harnesses in the set, thereby disconnecting all modules except for the CLM and the LVPS (and the LVPS wiring connector that goes to the motherboard). Disconnect the internal keypad as well.

the CLM standby light should go from yellow to green when you turn the projector on via the remote. If not, then the LVPS is bad... unless the IR sensor is bad, which is extremely rare compared to the LVPS.

If the set turns on with everything disconnected, and the belly fans come on, and the standby light goes to green, then you have a short somewhere in the set. Start reconnecting the boards and connectors until that function doesn't work any more.

The LVPS whine may just be 'singing' laminations of an internal transformer, and wasn't necessarily a sign of the LVPS failing.

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

Yeah the LVPS doesn't really blink any lights except when I pull out the power. And I've pretty much stripped the whole machine except the wires inside as I don't wanna bother taking the tubes out etc. but I'm fairly sure now that LVPS is the culprit.

Anycase, I made a move and just purchased over 60 caps Laughing

Dunno if there was any partlist available but counting and marking them was surely one of the most annoying tasks by far. Can't wait to spend a day in front of a soldering station!

Also thanks for the quick answers!

**Curt Palme** · Posted: Wed Sep 06, 2017 12:51 am Post subject:

Not to rain on your parade, but had caps aren't known in the Marquees overall at all. But.. give it a shot! Smile

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

I've recapped more than one failed LVPS and returned it to service, and it was nice and electrically quiet, too.

Nothing was done but recapping. Worked great!

**Curt Palme** · Posted: Wed Sep 06, 2017 4:09 am Post subject:

Really! OK, I stand corrected. May have to pull caps out of an old one some day to measure them.

mp20748 · Posted: Wed Sep 06, 2017 7:21 am Post subject:

The only caps I've ever experienced going or being bad were the 22uf (2 each) on the neck boards.

And it's been one of the wonders of electronics, in that all or most of those blue electrolytic's should be either bad or off value by now. And they are all on radical high frequency switching power rails. Where the switching power supply itself eats up the caps. And to add to that, most if not all are 85 temperature...they usually go bad from age and are the worst thing to use in a switching power supply because they don't handle high frequencies well at all.

barclay66 · Posted: Wed Sep 06, 2017 8:15 am Post subject:

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

Even caps that are not part of the "bad" lots, which fail prematurely, are still devices that are considered by the manufacturer to have a 10 year lifespan. They tend to last longer as their physical size increases but electrolytic capacitors are limited in their service life.

Yes, some will last 20 years. Or 30, and still be working well enough. But they do age and at some point they're going to fail to meet manufacturer's specifications and eventually they will fail.

With Marquees having been made since 1994 or earlier, and even the very youngest of them having been made five years ago, it should come as no surprise to find that some of them are having capacitor issues.

If you go into an LVPS for cap replacement, replace all the smaller ones because they're cheap and once you get started it doesn't take a lot more effort to do the rest of them.

When I recap an LVPS I use two sharpie markers. I tally up the caps and mark them with a red sharpie when they're counted.
As I replace them, I mark the new ones with a green sharpie. I recheck my work when I'm done, looking for only green marked caps,
or caps with no marks that I have decided not to change. (Or I mark those in a different color.)

Use only 105c rated caps where available.

It is acceptable to slightly increase the voltage rating if the proper rating is not available. Can't find 160v rated parts? Substitute 200v rated caps if you must. But don't reduce the capacitance value. And don't increase the capacitance value, either, unless you can't find the right parts. Slightly over-rating the cap value is better than under-rating it.

**Curt Palme** · Posted: Wed Sep 06, 2017 1:37 pm Post subject:

Well, the first projector I sold Kal back in... 2000? Was a Barco 800. He recapped the supply.. and remember, back then the set was only 9 years old.. and that stabilized the convergence drift. ONe day I will need to recap my two 909 SMPS and the H, V and convergence tray boards to see if that stabilizes the stack.

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

Thanks for the suggestions! My parade is soaked right now though, Curt was absolutely right. After around 4 hours and 56 caps later there's absolutely no change at all. Crying or Very sad

I think my choices are running low and just get a completely another LVPS unit. I'm becoming more paranoid too though, what if the problem is somewhere in the mobo or even clm after all? Recent changes I've made there was throw Curt's SWB in, which worked perfect while the fun lasted.

Cheers,
Eemil

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

Did you try to pull out the LVPS, plug in to mains, and found no fans spinning?
Then most probably the stand by section of the LVPS is faulty, have you checked Fuse F5 ?

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

In any case I'd take a look at that +24V line in the projector as well...

Meemil · Joined: 25 Mar 2016 Posts: 96 Location: Finland

Hmm you mean by testing the LVPS connector on the motherboard with multimeter? I'd definitely like to diagnose this further if possible!

Thanks,
Eemil

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary