The Binocular

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Re: The Binocular

Postby Harry Dalek » Sat Apr 27, 2019 11:39 pm

Some thing i was not expecting was perhaps not all 3BP1 crts are the same different result same circuit .i might have better results on the first CRT if i connect deflection plates to A2 .... at first i was thinking it was the transformers but does not seem to be the case which is better ..i will try connecting the deflection plates beam centering seems way off on this one .
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Re: The Binocular

Postby Harry Dalek » Sun Apr 28, 2019 5:45 pm

Well today was more lets see if i can improve results for the first 3BP1 ,connecting A2 to all the deflection plates tamed the beam to least display it ,the result is slightly off the far CRT's nicer raster dot .
I am not sure still if the magnetic field or fields of the transformers are effecting this, if so seems it has no effect to its neighbour.
I will check with the bench Ac power supply next time i have time sit down to work on this again ,even swapping CRT positions would show one way or another.
IMG_0610.JPG

I increased the High negative voltage to the result in below's image -1380 volts it swings up and down a touch due to mains voltage ,very close to the 1400 original supply of the Anderson monitor .
IMG_0609.JPG

I do have up to -1770 volts to play with but i think there would be a sparking problem if i use all this due to the matrix board and circuit lay out on the power supply board so perhaps not wise to go higher and kill parts ,i recall lay out lack of grounding kept killing the 74 volt zener's again on the Anderson monitor ...at the moment it seems to work fine at the voltages i have used before.
A note to my self for future CRT monitors and any one listening if using over 1500 volts spread parts lay out, might also be better to not use matrix board on the CRT circuit more for 3Bp1's can go up to 2000 volts .
Below video adjusting beam brightness control on the scope tube the other has a trimmer at the moment doing the same thing but i only have 2 hands and can only film with one and control the pot with the other :wink:
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MVI_0613_x264.mp4
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Re: The Binocular

Postby Harry Dalek » Fri May 10, 2019 7:02 pm

Still working on this when i can ,i ended up remaking my deflection amplifiers which set me back a bit i think originally had a warn trimmer playing up any case this one is balanced better.
I just remade the video deflection amplifier for now and Testing this today with the ramp circuits they are free running which would be under NBTV standard ..have to adjust turn the tube .
Again looks a lot brighter to the camera and defocused the scope tube again for now ,just wanted to see if they would work together .
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Re: The Binocular

Postby Harry Dalek » Sun May 26, 2019 8:54 am

Been on holidays first chance to work on the monitor since last posting ,got all the deflection part going on the scope crt really either or both could be a monitor or scope.
Been taking it slowly on this monitor and being very careful the voltages are deadly and crt tubes rare ,every thing seems ok on long runs so might now swap over to getting video and or the scope part going .

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MVI_0635_x264.mp4
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IMG_0634.JPG
bit of a mess still on testing bits
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Re: The Binocular

Postby Harry Dalek » Wed May 29, 2019 6:04 pm

Very minor improvement today got some thing up but lots of little problems to fix .
i have syncing problems need to correct track down the problem ,have a lower focus on the scope crt and see why ,i had found out on this project same type of crt does not mean they are the same in every way ......any case i also need to connect its time base just using the line freq here as a quick look here .
So not great yet but you can see what i have in mind here .
IMG_0664.JPG


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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Steve Anderson » Thu May 30, 2019 12:07 pm

I would expect you'd need separate controls for each CRT for focus and brightness. The internal construction of the electrodes should be the same but there are mechanical tolerances that will affect deflection sensitivity, grid bias and best focus voltage as a minimum. These are shown in the datasheets.

However, the tolerances are much better than semiconductor devices where hfe for example (basically current gain) can vary from 125-700 for one particular type of device. This also then varies with temperature, current and quite a few other factors - in fact a lot of other factors!

In both cases there will also be differences between production batches and manufacturers.

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Re: The Binocular

Postby Harry Dalek » Thu May 30, 2019 3:16 pm

Steve Anderson wrote:I would expect you'd need separate controls for each CRT for focus and brightness.


Hello Steve , Yes sir i have 2 test brightness controls one for the scope one for the monitor ,the monitor one is no longer needed only there for the raster tests ..your test circuit for the opto coupler.

The internal construction of the electrodes should be the same but there are mechanical tolerances that will affect deflection sensitivity, grid bias and best focus voltage as a minimum. These are shown in the datasheets.


mmmm yes i have found testing some 3bp1's as far as the hv voltages need tweaking more than likely very slight differences as far as construction of the things ...i notice you mentioned to me in the past even the same batch run of today's parts is better when needing same power supply diodes and capacitors .

However, the tolerances are much better than semiconductor devices where hfe for example (basically current gain) can vary from 125-700 for one particular type of device. This also then varies with temperature, current and quite a few other factors - in fact a lot of other factors!


Its more interesting to me than the little problem it is on the CRT's it was not expected but now i know ..yes less of a problem with today's parts ,talking of this i don't know if resistor change value over time but i have found on old 60 year or older they were way off some 100k all over the place wonder any thing worked !
In both cases there will also be differences between production batches and manufacturers.

Steve A.
[/quote]

Some thing to always keep in mind ...and be expecting .

Today a slight improvement again least its in sync !
The sync slice trimmer it works right towards one end of its adjustment and had to lower the line resistor R724 or its out of sync locked or not ..i still have to have a good poke around there in case some thing was not connected up right ...your circuit has worked 3 or 4 times now with no problems as always have to think its me that has caused this .
Getting there...keeping safe and fault finding ...now Another Anderson is born ! Thanks to Andrew and your self ...Shes a bit wonky still but i will try and do better.
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Last edited by Harry Dalek on Wed Jun 05, 2019 10:26 pm, edited 2 times in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Klaas Robers » Fri May 31, 2019 7:32 am

Why is your video signal on the left screen upside down? I see sync pulses peaking up in stead of down. And then I have the feeling that if you make the brightness of the left screen less, much less, that you get a sharper image.

Success!
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Re: The Binocular

Postby Harry Dalek » Fri May 31, 2019 2:51 pm

Klaas Robers wrote:Why is your video signal on the left screen upside down?
I see sync pulses peaking up in stead of down.


Oh the scope side of it still has not got its its own time base connected yet and still using the line frequency for this which is really fine for showing a line of video really , the video will be either i think upside down or right side up depending on the input from what ever i use as the player and the invert or normal switch to the first opamp ...but really i have not looked into this problem yet pointing it out its on my mind now Klass mostly just using main laptop as a player so just flip the deflection plates next time I use my soldering iron.

And then I have the feeling that if you make the brightness of the left screen less, much less, that you get a sharper image.

Success!


Yes Sir that does help reducing the brightness control for focus to the good enough point ..

Its to the point where it will display 32 line but fussy with most videos still but display it does ,it does need more work...i am pretty happy to get to this point thanks Klass .

There's a slight bit of wave to the video which i don't think is magnetic fields but i don't have any shielding so never know , the 12 volt dual power supply the transformer was just 2 connection 12volt ac type so used idea as below but with regulators so might be that that's easy to also check with a spare supply ...could also be the hv negative there are a fair few stages in the multiplier perhaps reducing the capacitor values are reduced this way on the filtering ...but also testing this with wiring all over the crts with different supplies this could effect the scan as well ...i will see when its a bit neater what is going on .
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MVI_0669_x264.mp4
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MVI_0661_x264_001.mp4
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MVI_0662_x264.mp4
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IMG_0666.JPG
IMG_0667.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Klaas Robers » Sat Jun 01, 2019 7:08 am

In the video demo with the dual grey-scale I see on the picture display (right) far too much contrast. You should see a black bar and bars in 7 shades of grey. I see only 2 or may be 3.

Flipping the vertical plates of the wave form monitor (left) is the good idea. Then you get a standard video wave form with the sync peaking downwards.

By the way this dual grey scale is a perfect (test)picture to align the contrast and brightness of the picture display (right). Then mark the video amplitude on the left screen and for future NBTV-video the amplitude between black and white should be equal to your marks. Then automatically the grey rendering (contrast and brightness) of the picture will be optimal.

Good luck!
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Re: The Binocular

Postby Steve Anderson » Sat Jun 01, 2019 1:27 pm

Another suggestion...reduce the amount of light in the room, it appears quite bright in the photos. This will allow you to reduce the CRT brightness and thereby achieve a better focus. The rendition of the grey-scale should be improved too, even so, it may still not be perfect yet.

We're used to being able to watch TV in a sunlit living room, even from CRT TVs, but these little (and old) devices were not capable of that. Just like a mechanical disc NBTV monitor they're best viewed in subdued light. When used in an oscilloscope application mostly there's only one line, whether it be a sine-wave, square-wave, whatever. Here we're spreading out that same amount of light over 32 lines. Something has to give.

Going back a few eons, if you look at the snapshots of my 3" DG7/32 display you'll see that the ambient light is very low yielding a much better focus and overall picture quality.

Steve A.
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Re: The Binocular

Postby Harry Dalek » Sat Jun 01, 2019 8:35 pm

Klaas Robers wrote:In the video demo with the dual grey-scale I see on the picture display (right) far too much contrast. You should see a black bar and bars in 7 shades of grey. I see only 2 or may be 3.


The room light and my camera didn't help its better on lower light this camera always makes screen shots brighter its better to the eye ,its a touch better now but yes also Steve's reversing wav video good for testing the monitors .

Flipping the vertical plates of the wave form monitor (left) is the good idea. Then you get a standard video wave form with the sync peaking downwards.


I had all good intentions to do this today but its on my to do list but got stuck into testing and mounting pots today .

By the way this dual grey scale is a perfect (test)picture to align the contrast and brightness of the picture display (right). Then mark the video amplitude on the left screen and for future NBTV-video the amplitude between black and white should be equal to your marks. Then automatically the grey rendering (contrast and brightness) of the picture will be optimal.


I will tried that on the next test it ,always good to learn more on test these monitors , i did test it before i checked the forum today and i will post some stuff up.

Good luck!


DSCN63461.JPG


The monitor displays much better now even on very weak video , problem was a slight reduction in the value of R301this to bring the video brightness up a touch and then i could reduce the input volume to the monitor which was causing it to play up on the wrong signal levels thinking my problem was the sync side of it but it was working fine now .
3BP1 NBTV Video Drive 1.gif
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Harry Dalek » Sat Jun 01, 2019 9:43 pm

Steve Anderson wrote:Another suggestion...reduce the amount of light in the room, it appears quite bright in the photos. This will allow you to reduce the CRT brightness and thereby achieve a better focus. The rendition of the grey-scale should be improved too, even so, it may still not be perfect yet.


Yes this is very true Steve i have of late tried viewing the camera screen more than what it looks like to my eye as its always very to too bright on the camera as to what i see direct .
Yep its not perfect but it seems to be improving a bit more each time i look into it so this is good.

We're used to being able to watch TV in a sunlit living room, even from CRT TVs, but these little (and old) devices were not capable of that. Just like a mechanical disc NBTV monitor they're best viewed in subdued light. When used in an oscilloscope application mostly there's only one line, whether it be a sine-wave, square-wave, whatever. Here we're spreading out that same amount of light over 32 lines. Something has to give.


I had been just looking at old adverts for tvs in the 30s and 40s in the late 40s they were selling their models as viewable in day light so the earlier sets must of been very dim only good for night viewing .
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Going back a few eons, if you look at the snapshots of my 3" DG7/32 display you'll see that the ambient light is very low yielding a much better focus and overall picture quality.

Steve A.


Chris long was saying something similar that crt's should be crt models to work at about 1000 v or over or they have problems with displaying correct grey scale ,i suppose they still do but viewing conditions come into play .

Focus on the scope is way off need more work on that side of the project ,i was working on the monitor side today .
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Last edited by Harry Dalek on Wed Jun 05, 2019 10:32 pm, edited 2 times in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Harry Dalek » Sat Jun 01, 2019 10:05 pm

Checking as i have noticed using my ipad the normal Mpg4 videos do not play on the older ipad i have here it should play on both ipad and pc
I was adjust brightness on the video a bit if wondering why the difference in bits

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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Binocular

Postby Harry Dalek » Sun Jun 02, 2019 2:14 pm

Today i reversed the deflection plates on the scope and added its time base to show more than a line and an amplifier to adjust the signal amplitude tried to take a video still its better to the eyes.
Had a spare TDA7231to adjust the scope waveform used most of this circuit , the free running ramp generator is just a copy of the line version apart from a pot to adjust the frequency
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Last edited by Harry Dalek on Sun Jun 02, 2019 5:37 pm, edited 2 times in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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