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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Sat Oct 17, 2015 6:15 pm Post subject: NEC PG9 does strange things |
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Does anyone have a hint on this? I already changed the big deflection board, but no improvement.
Projecting a black picture, photographed directly onto the tube face. The green looks the same.
 
Now with some window on the screen. The red tube is dim because my VGA-BNC cable has a loose contact.
Don't worry about that, using another cable doesn't have an effect on the pic.
Regards, Julian
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Marquee 9500U edgeblend P43 | NEC 9PG
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sat Oct 17, 2015 7:17 pm Post subject: |
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The first question regarding the plain PG always have tobe: are the capacitors still original in the machine?
-If yes, then -unfortunately- you most have to replace A L L the 300+ capacitors in the set if you want to ensure further reliable operation from the machine. Because the original capacitors are leaking out for now...
Just for a quick testing however you can try to pull out the POINT PWB to see if it helps for now.
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projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Sat Oct 17, 2015 8:48 pm Post subject: |
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Yeah 100 points for gjaki. I switched the point board with another one (before reading the reply) and boom! that works.
Strange thing is: The projector did this image distortion for the last 8 or 9 months everytime i switch it on.
But: After a few minutes of running with distorted picture, i used to switch it off and back on. Usually the pic was normal then.
But how can the point board cause this problem? I thought it might be some strange deflection error.
I think i will replace the caps on the point board (10 caps there) and see if everything runs fine then.
Thing is that i want to sell the PG9 and i want to sell a running pj. Thats why i want to fix this now, didn't bother me in the past,
i had enough to do with the marquees.
Thank you, regards Julian
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Marquee 9500U edgeblend P43 | NEC 9PG
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Sun Oct 18, 2015 1:10 am Post subject: |
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Leaking capacitors cause this on the point board. I've seen this a few times, I never bothered tracing out why, as I don't have the extender cards needed to get the board accessible while it's turned on.
I don't support PGs any more here due to the massive leaking capacitor issues. I have now gotten rid of all parts except for some new old stock tubes.
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hansilili
Joined: 09 Mar 2007
Posts: 302
Location: Köln, Germany
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| Posted: Mon Oct 19, 2015 10:15 am Post subject: |
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| gjaky wrote: | are the capacitors still original in the machine?
-If yes, then -unfortunately- you most have to replace A L L the 300+ capacitors in the set |
I tend to disagree with that part of the quote. I have been lucky with the caps on my NECs so far. But yes, the exact same failure of the point board happened to me too. If you want to recap it, DON'T PULL THE LEGS OF THE OLD CAPS but CUT THEM! I learned it the hard way myself.
CHeers!
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HansA, alles andere ist euer Bier!
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Oct 19, 2015 11:14 am Post subject: |
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I learned to use desolder wick to completely remove the solder from the legs and than remove. Else you might end up damaging the board.
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701s->runco933->8500ultra->cinemax->9500mp->919 splitpack + cinemax
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Mon Oct 19, 2015 7:32 pm Post subject: |
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I desoldered two caps (had only two fitting values laying around), it's kind of bugging, but totally doable.
And yes, they were leaking. But the pj runs fine now and since i don't want to really use it myself i won't rip it further apart
just to solder some money and time into it :=)
But thank you guys for the tips.
Rgards, Julian
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Marquee 9500U edgeblend P43 | NEC 9PG
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Oct 19, 2015 11:01 pm Post subject: |
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| hansilili wrote: | | gjaky wrote: | are the capacitors still original in the machine?
-If yes, then -unfortunately- you most have to replace A L L the 300+ capacitors in the set |
I tend to disagree with that part of the quote. I have been lucky with the caps on my NECs so far. But yes, the exact same failure of the point board happened to me too. If you want to recap it, DON'T PULL THE LEGS OF THE OLD CAPS but CUT THEM! I learned it the hard way myself.
CHeers! |
And we did tell you too 
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Oct 19, 2015 11:05 pm Post subject: |
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| redfox001 wrote: | | I learned to use desolder wick to completely remove the solder from the legs and than remove. Else you might end up damaging the board. |
You dont do that on these NEC boards, the best way is to pull the caps off the board leaving the legs behind and solder the new cap to the legs.
Desoldering the legs on these boards is asking for trouble, and now youve all been warned again, but anyone may feel free to think they know better if they really want to
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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Rattanee
Joined: 18 Jan 2015
Posts: 193
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| Posted: Thu Oct 22, 2015 8:32 pm Post subject: |
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I desoldered every single cap on my first PG9, didn't pull a single trace. Then again I have 20+years of experience with PCB desoldering and a good desoldering station  Unfortunately in my case my point board has some other misterious problem... probably a dud RAM.
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gregstv
Joined: 27 Aug 2007
Posts: 628
Location: Australia
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| Posted: Thu Oct 22, 2015 8:46 pm Post subject: |
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Pre-warming the board before removal and replacement of through hole components makes the process very easy.
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Rattanee
Joined: 18 Jan 2015
Posts: 193
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| Posted: Thu Oct 22, 2015 9:04 pm Post subject: |
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| gregstv wrote: | | Pre-warming the board before removal and replacement of through hole components makes the process very easy. |
Exactly. I don't have a preheater, but a hot air SMD gun in one hand, desoldering iron in other, works flawlessly even for boards with several layers. A hairdryer works in a pinch if it's hot enough.
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tschaeikaei
Joined: 08 Apr 2013
Posts: 490
Location: Germany/Saarland
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| Posted: Fri Oct 23, 2015 9:38 am Post subject: |
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It seems to be a problem that occurs often these days. Someone soldered on a motherboard or graphics card?
Crazy sh*t. These multilayer (more than two layers of copper) need so much heat to melt a small solder point,
you will most likely destroy any through-hole part you want to lift off.
So for the NEC, i agree that cutting wires and soldering new parts to the left wires is the easy and safe way.
The other way requires much more heat and effort, but the result looks better.
Too much heat could loosen the copper layer from the substrate.
Question is: do PCBs have to look good?
I think no. And in the future i will just cut legs go the easy way.
Regards, Julian
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Marquee 9500U edgeblend P43 | NEC 9PG
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