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SGIforever
Joined: 06 Jul 2009
Posts: 66
Location: Sweden
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| Posted: Fri Dec 14, 2012 6:08 pm Post subject: Increase scan rate on Barco Vision 701s? |
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I've found a Barco Vision 701s that looks interesting (from a price point of view  ), but some questions comes into my head.
Is it possible to increase scan rate on Barco Vision 701s to make it a Barco Data 701s?
Is there some "easy" board swap that make it scan to 50 Khz instead of 36 Khz ?
Otherwise, how capable is a BV 701s? I don't know how to calculate what a 36 Khz scanrate will give in terms of picturequality, but it guess it won't be enough for 1080i.
The BD 600 scans to 42 Khz and seem to be capable of 1080i.
Unfortunately the BV 701s is not in the "CRT Projector Specifications" nor "The Best/Worst CRT Projectors List", just the BD 701s.
Also, is possibly 10000 hours on the tubes something to stay away from? I haven't seen pictures, nor have I possibility to check the tubefaces.
Have a nice weekend
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fuchs
Joined: 27 Jun 2012
Posts: 153
Location: the NL
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| Posted: Fri Dec 14, 2012 8:53 pm Post subject: |
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10,000 hours likely means the tubes are toast.
You probably don't want to spend any significant amount of cash on it, nor drive any significant length to go and check it out.
Personally I wouldn't even bother, maybe if the seller makes some clear pictures of the tube faces.
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onkel fuchs' cheapskate cinema
NEC plain 9PG
Last edited by fuchs on Fri Dec 14, 2012 9:07 pm; edited 1 time in total
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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: Fri Dec 14, 2012 9:06 pm Post subject: |
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I agree, and without control board and deflection board changes, you can't change it from a Vision to a Data. I'd give $50 plus shipping for the HV quadrupler in it though.
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VideoGrabber
Joined: 09 Apr 2006
Posts: 933
Location: Michigan
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| Posted: Sun Dec 16, 2012 3:02 am Post subject: Re: Increase scan rate on Barco Vision 701s? |
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| SGIforever wrote: | | I don't know how to calculate what a 36 Khz scanrate will give in terms of picturequality, but it guess it won't be enough for 1080i. |
I'm not sure why you'd guess that (or why no one else here has disabused you of that notion), but the BV701 will handle 1080i just fine.
_________________
- Tim
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SGIforever
Joined: 06 Jul 2009
Posts: 66
Location: Sweden
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| Posted: Sun Dec 16, 2012 4:41 pm Post subject: Re: Increase scan rate on Barco Vision 701s? |
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| VideoGrabber wrote: | | SGIforever wrote: | | I don't know how to calculate what a 36 Khz scanrate will give in terms of picturequality, but it guess it won't be enough for 1080i. |
I'm not sure why you'd guess that (or why no one else here has disabused you of that notion), but the BV701 will handle 1080i just fine. |
Thank you. That is what I hoped. I have found this in avsforum "1080i is 33,7khz" , but also "It will do 480p, not 1080i"
The projector has been running in a plantarium for all these years, so I guess it has mostly displayed black/dark images of space. If that matters for the tubes.
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VideoGrabber
Joined: 09 Apr 2006
Posts: 933
Location: Michigan
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| Posted: Sun Dec 16, 2012 8:15 pm Post subject: Re: Increase scan rate on Barco Vision 701s? |
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| SGIforever wrote: | | Thank you. That is what I hoped. I have found this in avsforum "1080i is 33,7khz" , but also "It will do 480p, not 1080i" |
I'm not sure why they'd say that. I had a BV700 here (not 701, not 701s) for a while. It was stock, except it had Toshiba tubes in it, not Sony (I think they were higher output). It had no trouble with 1080i, though of course 720p was not possible. And maybe that's where the confusion arose... it can't do 720p which is "HD", and thus it can't do "HD", which includes 1080i.
The main limitation to the BV70x series was tied to one of their strengths... they were a very compact enclosure. That made it hard(er) to get in there to service, and crams the HV stuff into much closer proximity to the LV analog boards & signals.
| Quote: | | The projector has been running in a plantarium for all these years, so I guess it has mostly displayed black/dark images of space. If that matters for the tubes. |
Usage patterns make a huge difference in tube condition. Folks overdriving them on a too-large screen could fry the tubes in a few thousand hours. While on a smaller screen in a very dark room with lower max brightness, useful life could be well past 10,000 hours. By their nature, the wear on CRTs is a function of beam current and area illuminated. Small areas (star fields) can be adequately illuminated at much lower levels than trying to light up an entire screen. That doesn't mean though that the tubes might not have wear patterns that you will find objectionable on normal content. You'll need to either see them, or have the seller provide pictures.
_________________
- Tim
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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 Dec 17, 2012 2:41 pm Post subject: |
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Barco 700s used SD187 tubes
701 used the slightly sharper 07MS tubes
701s used brighter Toshiba 180 tubes
708 and higher mostly used even brighter and sharper P16 tubes. (early 708 still used the T180 tubes).
So each new model used slightly better tubes. In a planetarium condition where sets are mainly used to project black, I've seen high hour tubes be mint. THe overall focus will tell you how worn the tubes are, as the ES electron guns do wear over time as to focus just by being on. I'm guessing they will be usable, but will be a bit soft compared to lower hour tubes.
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VideoGrabber
Joined: 09 Apr 2006
Posts: 933
Location: Michigan
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| Posted: Mon Dec 17, 2012 3:59 pm Post subject: |
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| Curt Palme wrote: | Barco 700s used SD187 tubes
701 used the slightly sharper 07MS tubes
701s used brighter Toshiba 180 tubes
708 and higher mostly used even brighter and sharper P16 tubes. (early 708 still used the T180 tubes). |
Thanks, Curt.
So the BV700 I had must have had it's tubes replaced with T180's.
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- Tim
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