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 Post subject: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Mar Fri 29, 2019 6:48 am 
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Location: Granville Summit, PA
I think its better designated a 5-something-p16. No, I didn't happen to fall on a way to reevacuate and bomb it again, but i found another one that plays. The camera sees it a little different than i do, and both eyes dont agree with each other on what theyre looking at either. but it is something visible.

As I'm looking at it the darker shades are like a dark purple, and drops into the higher blues with higher beam intensity. I notice the blues more with the left eye since that has new hardware in it as opposed to the right eye, which I'm seeing the dark purples more and not so much the blues. Pre-op observation :wink: ive also noticed the blue component begins to diminish as the phosphor ages with use, as ive noticed when there is a solid field shown. Anyway, it plays, im happy with it, and what can i say, im impressed


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Mar Sun 31, 2019 10:01 pm 
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Location: Tyngsborough, Massachusetts
Brian,

Thanks for posting this. I just acquired a B&K 1076, and even though it's not intended to be used that way, I wondered what an image would look like on the 5BKPV-1 tube. After I go over mine for parts upgrading, I 'd like to try to put an image on mine, also.

Jeff


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Mar Sun 31, 2019 10:47 pm 
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If it helps i didnt use the b&k 1076 to play this on. Ive previously retuned something else to play the older crts without doing possible damage to them or having them throwing x-rays.


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Thu 18, 2019 7:35 pm 
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Joined: Nov Wed 27, 2013 5:59 am
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Location: Metzger Oregon
I was hoping there would be more discussion about this CRT, as I have one that I thought might be useful for a future project. Is there any risk of UV exposure? It looks like the phosphor is aimed toward that end of the spectrum. Also, are there any TVs where this would be a sub? I know of 7" and a few 3" sets, but I am not aware of anything in between - but that doesn't mean they don't exist. It would be nice if this could be used to replace a hard-to-find CRT. You don't mention much about your "something else" that you have it connected to.


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Fri 19, 2019 2:36 am 
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Joined: Aug Tue 04, 2009 2:15 pm
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Location: Elmira, NY
I would be interested to know if you could substitute a standard tube ,(with P4 ). Would the photo tube pickup the signal or does it only respond to UV.


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Sat 20, 2019 12:04 am 
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General purpose phototubes typically will respond to a pretty wide spectrum of visible light, though they favor the blue-violet end of the spectrum. I think the UV phosphor CRT used in B&K's scanner just takes advantage of the extra sensitivity, and probably also has a faster decay time for better resolution. But I haven't studied the response data for the CRT and PM.

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A collector of TV signal boosters and UHF converters -- God help me!
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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Sun 21, 2019 2:42 am 
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Location: Elmira, NY
I’ve toyed with the idea of building a home brew flying spot scanner with a standard p4 tube. One could reverse the deflection coil polarity of a crt set and place the photo tube , or even a SS photo-diode/transistor to pick off the video ahead.


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Mon 22, 2019 1:21 am 
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The tube is made for both the rapid decay and the photo tube. P4 would work for that application, like a 5ax, but p4 is slower decay which may be noticeable with a slide in place in front of it. I dont think the uv emission is hazardous. It will light up the crt faces in the monitors near it though.


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Tue 23, 2019 3:51 am 
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I just got an aluminized version of this same tube made by sylvania. It was listed as new in the box but i dont see any getter so im not too optimistic about it


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: Apr Tue 23, 2019 4:17 am 
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It doesnt look fishy. Its clean and has the pin cover on it. But i try to play it and its going bananas. first i have the whole neck lighting up like a christmas tree, then threw x-rays, then when i started it up again it seemed to have stabilized started playing then nothing but raster while g2 and a1 are glowing then starts playing again. It eventually goes bananas again throws x-rays and stopped there.

Well, my collection of duds just got a little bigger


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 Post subject: Re: The B&K 5BKPV-1 - Heres what it looks like
PostPosted: May Sat 18, 2019 5:39 pm 
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Location: Phoenix, Arizona
The primary reason the UV phosphor CRT was used in the B&K scanners was the very, very short persistence. If a P4 tube was used the video would smear so bad it couldn't be seen.

The Photo multiplier tube was upgraded through the various models of the scanner to a version that was a good bit more sensitive than the original 931A developed in the 1940's.

With a fairly dim raster the video output from the multiplier tube is a full 1 volt due to the gain of the PM tube without much noise.

The PM tube is responsive to a wide spectrum of light and regular indoor lighting will wipe out the scanned image if you lift the lid on your 1076.

The original version was called a DynaScan model 1000, so the TV installer could have a signal to test the new home TV when there was only one station that signed on at 5:30 in the evening.

Of course now days there are no station on the air any time of day with analog TV.

Jim


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