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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Mon Jul 15, 2013 2:08 am Post subject: Marquee 8500: skewed blue tube |
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I just installed "new" tubes in this Marquee 8500. The tubes were complete, with all of the magnetics mounted so it was supposed to be a drop-in replacement for some dead tubes (killed by P14 overvoltage). The issue looks like magnetics or deflection related, but short of me randomly poking around I would like to ask the experts: what could be wrong with this? The G2/drive adjustments seem to behave different on the blue tube than the other tubes, which may not be related to the faint skewed pattern shown attached to this post.
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Mon Jul 15, 2013 2:24 am Post subject: |
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Without the G2 set this high, I was not able to get any image - the entire raster is lit with a faint skewed image or it's just black.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Jul 15, 2013 2:50 am Post subject: |
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Adjust the center line H skew in the convergence...
Turn the G2 down...
Turn the white level up on the blue.
Have you got the yoke connections the correct way around?
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barclay66
Joined: 27 Jun 2011
Posts: 1304
Location: Germany
TV/Projector: Marquee 9500 Ultra
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| Posted: Mon Jul 15, 2013 8:28 am Post subject: |
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Hi,
Before working on the electronic controls, I would suggest tuning in the mechanical components first. The less work You leave to geometry/convergence circuits the less heat they will produce and therefore less drift.
It is not uncommon that a replacement tube could show a slightly tilted picture. After all, the factory pre-alignment often is long ago and external environment conditions (e.g. magnetic field of earth) and deflection settings (e.g. reversed vs. normal) have an influence too.
We discussed yoke rotation before: http://www.curtpalme.com/forum/viewtopic.php?p=340858
Regards,
barclay66
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Mon Jul 15, 2013 11:50 am Post subject: |
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It doesnt really look like a yoke rotation issue though, the horizontal lines are tilted within the raster
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Tue Jul 16, 2013 3:46 am Post subject: |
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Thanks for the responses! I'll give those things a try in the next few days.
| CasetheCorvetteman wrote: |
Have you got the yoke connections the correct way around? |
Based on the colors of the wires/and the pinouts yes...but it's a distant possibility that the yoke connections are flipped on the manetics themselves, so I'll verify that as well. It is curious that the raster is being scanned correctly...so I'll work under the assumption that the magnetics are actually ok.
Thanks for the info barclay66 - I'll take that into account when getting the rest of the PJ up and running.
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jul 16, 2013 4:43 am Post subject: |
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Ive seen PGs do wierd things with the connections backwards.
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Tue Jul 16, 2013 5:20 am Post subject: |
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| CasetheCorvetteman wrote: | | Ive seen PGs do wierd things with the connections backwards. |
Yep like funky picture distortion not that behavior
The g2 is higher then it needs to be for sure on the blue tube(turn it down)
Look over the info curt has on here(under the marquee section) and find out what needs to be adjusted to get the blue tube back to regular brightness with the g2 at a normal level
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jul 16, 2013 7:29 am Post subject: |
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No ive seen that sort of thing happen too.
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Tue Jul 16, 2013 7:32 am Post subject: |
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| CasetheCorvetteman wrote: | | No ive seen that sort of thing happen too. |
It is mentioned in the setup and layout section on the nec 9pg(had to read it in order for me to change my pg from cealing mount to table/floor use)
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Tue Jul 16, 2013 11:41 pm Post subject: |
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| the big E wrote: | | CasetheCorvetteman wrote: | | No ive seen that sort of thing happen too. |
It is mentioned in the setup and layout section on the nec 9pg(had to read it in order for me to change my pg from cealing mount to table/floor use) |
You dont say? Ive done it a few times before ya know 
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Tue Jul 16, 2013 11:45 pm Post subject: |
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| CasetheCorvetteman wrote: | | the big E wrote: | | CasetheCorvetteman wrote: | | No ive seen that sort of thing happen too. |
It is mentioned in the setup and layout section on the nec 9pg(had to read it in order for me to change my pg from cealing mount to table/floor use) |
You dont say? Ive done it a few times before ya know |
Just thought I'd mention it
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Thu Jul 18, 2013 2:37 am Post subject: |
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Ok, I've got the G2 adjusted correctly based on the raster...but I am unable to get the brightness back. The original problem has disappeared - the image is aligned correctly (no skew) but is extremely faint at 100% brightness and 100% drive. Could the video level from the VIM or the CLM be too low? Could I swap the video lines (at the rear of the tubes) between the green and blue tubes for test purposes?
If necessary, I could measure the video inputs with an oscilloscope.
I haven't tried an external video source with projector yet - only using internal test patterns.
P.S. I couldn't find any tips on returning the brightness back to normal levels.
Thanks!
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Nashou66
Joined: 12 Jan 2007
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Location: West Seneca NY
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Perry
Joined: 04 Mar 2011
Posts: 25
Location: London, Ontario
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| Posted: Thu Jul 18, 2013 2:59 am Post subject: |
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It was 6.25 the last time I measured it.
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Thu Jul 18, 2013 3:03 am Post subject: |
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I agree with Nash over voltage will burn out the tube heaters quickly
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the big E
Joined: 20 Apr 2013
Posts: 1928
Location: speedwell Tn.
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| Posted: Thu Jul 18, 2013 3:10 am Post subject: |
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| Perry wrote: | | It was 6.25 the last time I measured it. |
Sounds like the tube heaters are not working or have burned up in the blue tube(it will cause this issue) try swapping around the neck boards and if the problem follows then its the neck board if not its the tube
Sorry I can't help otherwise given the tube heater voltage is normal
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