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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Mon Apr 08, 2013 9:40 pm Post subject: Help with a malfunctioning runco dtv 991 (xg 75/85?) |
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I've been back on these forums for a few days trying to read up on an 1100 I just picked up. Its got me thinking about a 991 I got some years ago that was taken out of a cilents house due to a failed red. Been sitting in my parents basement for quite a while. I just went over and had a look at it again.
It powers on, but no red. The red tube "glows" and is lit at the tip, so evidently there's power there. I'm pretty sure that when I first got it, I sent curt an email, and he suggested trying the board on the end of the tube - which I got from him. I'm sure it wasn't much at the time, so was worth trying, but no go.
Anything else simple I can try or test, or should I think about just getting rid of this thing? Would be nice to put into operation if it could be done on the cheap.
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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: Mon Apr 08, 2013 10:54 pm Post subject: |
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Be VERY careful at this point. Turn the set on, look into the red tube. If you see a glow at the extreme top or bottom of the tube face, you have a defective vertical board, and running the set the way it is will almost certainly implode the tube. Even with the low hour count, the fact that you have green tube wear makes the set almost worthless at this point, unless you want to set it up and use it. It will throw a decent pix once the red is repaired.
If the red tube is completely dead, make sure one of the pins on the red CRT isn't bent over, that's common, and will cause no red output. Otherwise, if you've swapped the CRT tube socket/video amp, then the problem will most likely be on one of the boards in the card cage. Rare, but possible.
I assume that the red test patterns also do not work?
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Tue Apr 09, 2013 1:53 am Post subject: |
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Thanks curt. None of the test patterns work on red. Pictured is the "white" test pattern which should (I presume) simply output each tube full on.
I looked into the tube, and I don't remember seeing any glow top or bottom. You could tell it was "on", but it was even. I'll check again, and also look for any bent pins. I was just going to give this to my friend who's been using my old 1272 with 9000 hours for several years. Its picture is quite bad at this point.
I did find it strange to have visible wear with the low hours on the meter.
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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: Tue Apr 09, 2013 2:01 am Post subject: |
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OK, so it's a video issue. swap the neck boards one more time to be sure, but then it will be in the card cage, on the left side, one of the cards behind the BNC input connectors. Ive got all of them for cheap if you want.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Apr 09, 2013 2:15 am Post subject: |
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HOLD ON HERE!!!
Have you pressed KELVIN and wound up the red W and B settings to see what happens??
That is an XG75, and someone stole the black painted case...
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Tue Apr 09, 2013 2:41 am Post subject: |
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| CasetheCorvetteman wrote: | HOLD ON HERE!!!
Have you pressed KELVIN and wound up the red W and B settings to see what happens??
That is an XG75, and someone stole the black painted case... |
I didn't try that - does that function create a total fade out of the channels? Will try that before I do anything else. As I've said, the red seems to be "on" - just nothing to see.
Will post a follow up and go from there. I wish it did have the usual 991 black case. I guess they ordered white at the time because in spite of the room being a dedicated theater, they for some reason went with a white ceiling.
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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: Tue Apr 09, 2013 2:46 am Post subject: |
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If the red video amp isn't working, then it will do all sorts of weird things since the red tube isn't drawing current.
Swap the video amp one more time, and let me know.
Some Runcos did indeed come in white...
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Tue Apr 09, 2013 2:53 am Post subject: |
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Just to confirm - this is the piece I'm replacing, correct? I believe this is what I got from you way back - or the original rather.
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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: Tue Apr 09, 2013 3:02 am Post subject: |
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Yup. I've got more here if you need one. It is also possible for a bad tube to take out that board. Check for a burned resistor near the CRT socket. Might be an SMT one on the back of the board, I can't remember.
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Jeremy112
Joined: 28 Sep 2006
Posts: 2649
Location: Fond du Lac, WI
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| Posted: Tue Apr 09, 2013 3:19 pm Post subject: |
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| CasetheCorvetteman wrote: | HOLD ON HERE!!!
Have you pressed KELVIN and wound up the red W and B settings to see what happens??
That is an XG75, and someone stole the black painted case... |
Think the black case had ore value than the PJ? 
Keep working on the projector Baltor, The XGs are worth messing with, and I've already had a tube crack, replaced all 3 tubes, spent endless nights setting it up, but she is one nice machine, looks as good as a high resolution CRT monitor when using a PC on it.
If you DO get it going, and you DO use a PC... Set the "Phosphor saver" to ON, and lower contrast and brightness to the 50s, as this will prevent tube wear on the XG with PC signals.
I did this after burning up my tubes on a worthless video game, they have not gotten any worse since, so I WISH I WOULD HAVE DONE IT A LOT SOONER.
Make sure you do and you'll be a happy camper 
_________________
When I'm asking for a Model number, that doesn't mean I'm asking for a nude photo with your number on it 
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Jeremy112
Joined: 28 Sep 2006
Posts: 2649
Location: Fond du Lac, WI
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| Posted: Tue Apr 09, 2013 3:24 pm Post subject: |
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| Curt Palme wrote: | If the red video amp isn't working, then it will do all sorts of weird things since the red tube isn't drawing current.
Swap the video amp one more time, and let me know.
Some Runcos did indeed come in white... |
Call me nostalgic, but I love the old white look of the XG Projectors, they are very pointy and boxy, have lots of cooling "gills" I think the white gives the XG its character that I enjoy. When I retire it, it will be saved for retro-gaming. Even with tube burn it impresses 
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When I'm asking for a Model number, that doesn't mean I'm asking for a nude photo with your number on it
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RayN999
Joined: 25 May 2010
Posts: 207
Location: Minneapolis, MN
TV/Projector: Sony VPL-VW60 and Toshiba 65H84 CRT RPTV
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| Posted: Tue Apr 09, 2013 4:01 pm Post subject: |
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Here's what I saw at Jeremy112's place last fall...
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_________________
Ray Nelson
N9QBV
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Jeremy112
Joined: 28 Sep 2006
Posts: 2649
Location: Fond du Lac, WI
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| Posted: Tue Apr 09, 2013 4:11 pm Post subject: |
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Ray, I forgot you took that pic
The projector still sits exactly like that, hasn't moved a millimeter , just had to redo the tape a bit so I could access the insides 
I should note, unless you live without pets, this is not recommended for obvious safety reasons
Also, note how the projector mount is on the projector, but not on the ceiling
_________________
When I'm asking for a Model number, that doesn't mean I'm asking for a nude photo with your number on it
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Wed Apr 10, 2013 2:27 am Post subject: |
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Back again!
I spent some more time with the 'ol mule tonight. I checked the kelvin setting - it was halfway, so red should be on. Was a good thought.
It also turns out the 'video amp' I have isn't the same as the one in the projector. I could have sworn I swapped it, but I guess not. My memory is poor.
Here are some pics of the boards (the one I pulled off the projector is on the right - the one I 'thought' I had swapped out is on the left)
Whats availability like on these curt? I feel so close.
jon
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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: Wed Apr 10, 2013 2:38 am Post subject: |
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Guaranteed its a bad neck board. I've had a bunch of them die in the last year or two. You have the LC version of the neck board. Also found on XG85s and XG751s.
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Wed Apr 10, 2013 2:47 am Post subject: |
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Ok. Will send you a PM.
One other thing. I noticed while the menus/test patterns were up, the imagine had a very slight "jitter". I don't remember that last time I fired it up.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Apr 10, 2013 3:25 am Post subject: |
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@Jeremy112, the black case and big glowing RUNCO sign certainly look WAY better than the standard XG cover. Also easier to keep clean
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baltor
Joined: 06 Apr 2013
Posts: 14
Location: Toronto
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| Posted: Wed Apr 17, 2013 12:32 am Post subject: |
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I sourced a neck board locally, and still no go. I did try swapping the "p0gr" red and blue which caused the cutoff to be reversed. Blue had output, and would shut off when the red cutoff button was pressed. Hope I didn't wreck anything! I seem to remember someone suggesting that before. Anyway, not sure what else to try.
The tube is definitely powered, and "flickers" when I hit the cutoff button... so there's something there. I just don't know enough about how these work to make an educated guess.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Apr 17, 2013 3:58 am Post subject: |
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Interesting...
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Wed Apr 17, 2013 10:46 am Post subject: |
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| baltor wrote: | I sourced a neck board locally, and still no go. I did try swapping the "p0gr" red and blue which caused the cutoff to be reversed. Blue had output, and would shut off when the red cutoff button was pressed. Hope I didn't wreck anything! I seem to remember someone suggesting that before. Anyway, not sure what else to try.
The tube is definitely powered, and "flickers" when I hit the cutoff button... so there's something there. I just don't know enough about how these work to make an educated guess. |
I don't know if it is legit to swap only 'POGR' and not swapping the rest of the connectors, as the tube current is always monitored, and confuses the projector if the driving is different from the measurement. If you swapped RED and BLUE neckboards with all of its corresponding connectors, and the problem does not follow your neckboards, then the problem is coming from either the VIDEO OUT board or GAIN CTL board.
_________________
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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