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chillman
Joined: 09 Apr 2007
Posts: 134
Location: Germany, Bavaria
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| Posted: Wed May 26, 2010 5:04 pm Post subject: Marquee killed its HVPS ... again |
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Hi everyone,
yesterday the spare HVPS I bought a few weeks ago, died too.
When powering on the projector you can hear a fast ticking sound, then the RCD will shut down
power to the room. As I was told when my first HVPS died, the ticking sound means there's a short in the potted
section or something like that. At least there's gotta be a short somewhere as the RCD kicks in.
So my question is: Which parts in the projector can kill the HVPS? When I got the Marquee it was at least on it's second HVPS, as it had a HVPS from 2004 in it.
Or do you think that's a coincidence?
Greetings!
Tillman
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Wed May 26, 2010 6:42 pm Post subject: Re: Marquee killed its HVPS ... again |
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| chillman wrote: | Hi everyone,
yesterday the spare HVPS I bought a few weeks ago, died too.
When powering on the projector you can hear a fast ticking sound, then the RCD will shut down
power to the room. As I was told when my first HVPS died, the ticking sound means there's a short in the potted
section or something like that. At least there's gotta be a short somewhere as the RCD kicks in.
So my question is: Which parts in the projector can kill the HVPS? When I got the Marquee it was at least on it's second HVPS, as it had a HVPS from 2004 in it.
Or do you think that's a coincidence?
Greetings!
Tillman |
I would replace the LVPS because that's what drives the HVPS and there could be a problem with the 385VDC delivery? I can't think of any other reason for HVPS to repeatedly fail, especially a newer one from 2004
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chillman
Joined: 09 Apr 2007
Posts: 134
Location: Germany, Bavaria
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| Posted: Wed May 26, 2010 8:02 pm Post subject: |
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Out of curiosity I chipped away some of the sealing.
There's a spot on the upper PCB which is totally burned (see picture).
I guess there once was a connetion between the upper PCB and the transformer.
So, could this be caused by a faulty LVPS?
Greetings!
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed May 26, 2010 9:13 pm Post subject: |
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perhaps paul butler still has his lvps for sale on ebay, its a modified lvps with silent fans filament mod and a lot of parts replaced.
_________________
1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Sat May 29, 2010 6:56 pm Post subject: |
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| chillman wrote: | Out of curiosity I chipped away some of the sealing.
There's a spot on the upper PCB which is totally burned (see picture).
I guess there once was a connetion between the upper PCB and the transformer.
So, could this be caused by a faulty LVPS?
Greetings! |
That's a common failure, bad diodes in the potted section
| draganm wrote: | | Hi Scott , Mike and Tim. A few months ago I and a EE friend embarked on a mission to repair the Marquee HVPS. Yesterday we made a breakthrough. It appears that the Achilles heel of this unit on the potted side is Resistor R95. This guy spans the gap between the fly-back trans. and the row of Caps which sequentially charge the Anode out. after excavating the silicone we found R95 had burned up pretty badly, it was a really all charcoal and ashes.The trouble is we could not identify the values of this part. the schematic I have has only a Question mark here. |
| mp20748 wrote: | When that resistor burns, it's an indication that one of the multiplyer diodes is shorted. Replacing it with another resistor, would yield the same results.
There are better diodes that could replace the ones in there, but they are so hard to get to.
mike |
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