PhonoVision Mechanical video recorder Version 3

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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Thu Jan 20, 2022 2:31 pm

Worked on the problem of holding the embossing Disc in place ,this ended up an easy fix as shown but when embossing can cause the disc to stall need to test it ,i also added a opto switch to the plater as a speed indication for a start so things may change ...also added plater and embossing lathe Pot knob Scale's should be easier to keep correct working speeds .
I haven't added the cartridge's yet just to keep them safe till testing ,i also need some very thin wires for the play back arm so they don't effect the play back arm's movement .
Getting there :wink:
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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Fri Jan 21, 2022 7:41 pm

Still a few more things to do on the to do list ,but today i worked on the control panel and holding the embossing and play back arms when not in use ,need to still add perhaps another little panel for the sound control inputting out putting such ..this is all trimmers and circuit board connections .
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DSCN6923_Segment_0_x264.mp4
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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Fri Feb 04, 2022 8:18 pm

Well may notice i have the old HD platter mount on the cork to help dampen any vibrations so lifted the bed a bit , i also got stuck into working out a way to monitor the platter speed on the scope with a reflective opto switch and a one platter rotation indication via a Hall effect sensor have a little cut rubber magnet you can find on fridge magnets and this case from a tiny bush less dc motor.
The idea came in handy for speed control on the mark 1 and 2 ,i wouldn't mind stable auto speed control but the sensors are what are needed in the first place ,i ditched the original one rotation opto switch for the hall effect sensor just due to the swipe arm bolt got in the way of the other opto switch mechanical problem .
So a little side tracked for the week thinking about and mounting testing these ,it will give me a way for a start to monitor and control the geared motor .
Attachments
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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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sun Feb 06, 2022 7:13 pm

Finished off the encoder circuits today and hooked up the ceramic cartridge's
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[attachment=0]A3144_Film-800x445.jpg[/attachment
The hall effect sensor used ,they are either south or north pole types so only work on one of these poles depending what you have ,just using the encoder disk and both sensors for now as a platter speed indicator using my scope ,there's a slight wobble does not take much for the sensor to pick this up it would be the paper encoder disk causing this with a pulse width varying i will have to remove more paper around the mounting ring .

There isn't really that much more to do just wire in the cartridges to the circuits test how well it will emboss a dvd i should call it a (AVD Analog Video) disk recorder player a lot has to have been done right for all this to work :shock:
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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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Thu Feb 10, 2022 2:54 pm

Ok on the record side of the project the disk embossing looks to be working ,i am happy with what i am seeing here so far ,need look into the play back side now .
Below the first test recording played around a little with speeds for a narrower track you can see in the photo the NBTV is recording on the tracks.... how well i will find out when i get my play back side operating .


I now need to test the Phono Preamplifier (RIAA Equalisation) circuit 2 of them circuit on page 2 , i vaguely remember testing them a year ago any case need to output these to a phono socket....below todays work hooking up the stereo amplifier transformers to the embossing cartridge and adding the AM/PWM switch which feeds the audio to the Lm1875 amplifier
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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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sat Feb 12, 2022 11:31 pm

Today working on the tone arm amplifier ,i had one built last year but found it a bit noisy so swapped to day to a LA4285 3watt amp, i had the ic in my junk box so made use of it .Seem to work well enough.
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b1223ba8567d92a0d9926d0d5e203d60.jpg (24.37 KiB) Viewed 1199 times
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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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sun Feb 27, 2022 12:27 pm

After some tests for stable speed on play back i had to change the design to rotate the platter number 3 infact !
i found the first idea worked well at a small speed change and i wanted to play back my past phonovision disks so change to this belt drive geared motor idea
DSCN7410.JPG


But i found on sstv and video the dc geared motor would not cut it as far as stable speed control .

Now i have swapped to a stepper motor to run off the mains frequency which cuts down the noise vibration and is a synchronous motor better than the last type i used a asynchronous motor .
So at the moment i will be stuck with one speed but at least i will know recordings and play back should be the same speed it has a lot of torque for the recording side .
Attachments
DSCN7415.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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Tue Mar 08, 2022 1:16 pm

Not posted for a while but i did get first results images ,the stepper motor does work on video record to correct play back speed but i think due to the tension on the pulley rubber its a bit wavy some thing i didn't get on fiction drive last time around .
Any case at the moment rebuilding the preamp and amplifier for play back as i think the current idea could be improved on .
I will work on it more Thursday .
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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sun Mar 13, 2022 5:48 pm

Today i realised a problem i had forgot about picking it up on SSTV recording so i will mention it here as its pretty important if any one wishes to try this .
The weight of the embossing arm head has to be correct and this has to be worked out by trial and error as what ever you use is going to be different ,it has to be enough to not effect the disk motor but enough to make the track groves on the record deep enough ..some thing i forgot was the weight will push up the needle into its cartridge to much so its not embossing correctly making the tracks pushing downwards ,the weight can drag the casing also , a tiny bit of foam between the needle arm and its holder fixes this problem ,some thing only needed on the record side .
There are a hell of a lot of problems trying this sort of project not an easy one !
I have been using a stepper motor on mains frequency which i can't really adjust the speed on the recordings for NBTV its showing swing on the line recording which makes me wonder if the mains frequency is varying ..voltage does .
A little confusing as with the Asynchronous motor on mark 2 i had a speed problem but i can't say it was as bad as swinging as much as here i checked the pulley tension this didn't effect it much .
Also explaining it here when you record on a record there is friction which ever so slightly effects the record speed i suppose depending on the torque of your motor ,the effect on play back you noticed it more on slower tv systems as in SSTV, 8sec is about half out of sync on play back but on slower sstv systems it just gets worse.
Below is a 8sec b/w but now out of sync on play back
DSCN7426.JPG

The program i am using has slew control after its recorded to fix it a bit
DSCN7423.JPG

If you look at the record lines lining up not to bad but not perfect if you speed things up to NBTV speeds these lines will look very wavy which i will show later below .
Back on SSTV here is what happens at slower higher line systems
robot 72 colour a fix of cause would be change the frequency driving the stepper motor to the correct play back speed ,any case it was very useful for a slow scan test today to see how it operated.
DSCN7429.JPG

Now on to NBTV results so far poor due to the record line fluctuation (lines not lining up pretty much ) and so you see what speeding up the problem looks like not very good at all but fixable in time got to show the good with the bad :roll: PhonoVision is not easy hopefully next time i post i have improved things .


This is the video i was trying to phonovision record
NBTVIDEO.WAV
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DSCN7452_x264.mp4
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DSCN7460_x264.mp4
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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: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Mon Mar 21, 2022 10:41 pm

I just working on some variable control of the stepper motor ,i have a micro step board on the way ,in the mean time i am working on an idea where i use a normal step circuit filter the control steps to a sine wave steps and then fed it to the driver so analog ...micro steps are just trying to produce this waveform any way ...
Reason found the stepper runs rather well on on sinewaves a variable one would be more useful on play back with any speed change due to recording .
Any results i will post
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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Fri Mar 25, 2022 6:29 pm

The sine wave idea just worked on the bipolar circuit but the unipolar motor circuit i am using the filtered square to sinewave was a bit low and didn't ...so again still wait and see what the micro stepper board does when it gets here ..
I can then compare the motor running at 50hz, my current board has 2 clocks a 555 and a crystal a 2 way bet ! i should by rights be fine with the crystal controlled stepper for record play back but just in case as every other case i was thinking fiction has slowed the recording a touch so then on play back will be a bit off then needing a variable clock for play back be very happy if i can stick with the crystal then it might of just been down to mains frequency was varying ?
The Stepper is running pretty smooth on 50hz vibration not to bad no worse than the mains frequency idea i was using to drive it before ,i will see if can do some recordings tomorrow when i remount the motor and see if there's any improvement.
.
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: PhonoVision Mechanical video recorder Version 3

Postby smeezekitty » Sat Mar 26, 2022 10:24 am

I highly doubt mains varies that much. Most likely you have some variance in the drive system or varying loads on the system
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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sat Mar 26, 2022 12:12 pm

smeezekitty wrote:I highly doubt mains varies that much. Most likely you have some variance in the drive system or varying loads on the system

Well testing mains on a HV transformer out putting 270v that can vary 10 volts since its swinging the frequency must as well ...not a perfect clock the old mains !
Having tested it on a SSTV recording on crystal clock motor control its still a touch off play back to recording ,easiest thing would be record a frequency and see what frequency it plays back at .
I am very happy with the record quality on the video side here on old 8 sec sstv i will try NBTV today as well i think i will still have the result but see how it go's.
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DSCN7474_x264.mp4
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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: PhonoVision Mechanical video recorder Version 3

Postby smeezekitty » Sat Mar 26, 2022 12:59 pm

Harry Dalek wrote:
smeezekitty wrote:I highly doubt mains varies that much. Most likely you have some variance in the drive system or varying loads on the system

Well testing mains on a HV transformer out putting 270v that can vary 10 volts since its swinging the frequency must as well ...not a perfect clock the old mains !

Mains voltage isn't that stable due to varying load but frequency is generally pretty stable because the power grid is made up of synchronous generators which have a lot of inertia and won't change readily.

That is quite a nice SSTV recording
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Re: PhonoVision Mechanical video recorder Version 3

Postby Harry Dalek » Sat Mar 26, 2022 3:10 pm

smeezekitty wrote:Mains voltage isn't that stable due to varying load but frequency is generally pretty stable because the power grid is made up of synchronous generators which have a lot of inertia and won't change readily.


Well yes the mains idea worked pretty much ok last time around so with only a little wobble on the frame,i can see the sine wave on the frame on NBTV which soils it ,must be external looking at tests today i must be either recording it playing it back both ,running this motor at 50 hz .
I know i had a felt cloth on the MK2 this one is disk to all metal a vibration might be making it to the recording i will look into that i can also change the speed now so could try a different record play back speed and check the results .

That is quite a nice SSTV recording


I tried robot 72 colour bit more fussy but got an image ,nbtv results no different so show results when i get it better.
DSCN7479.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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