Mindset "Televisor" kit

[Dave A]

I'm starting a new thread on this kit so as the Yanczer thread stays on course and add some explinations of what we are chasing. It is a science fair kit from Mindset UK that reproduces a 32 line mechanical television from the 30's and it is quite a good display to show the concept. Modern circuits and a plastic true-to-form copy in miniature of the Baird Televisor. it comes with an onboard "test" chart and an audio input from a CD with other NBTV 32 line displays. You will never confuse the two.

It looks like two of us working on the new version now. If anyone has the "old" version, please join in. The old version had a motor main board that was constructed in the old school with parts standing in the air away from the disc. Think a 1965 transistor radio. The new version moves the subminiature surface mounts to the disc side of the motor board. Think a tv remote control.

I have an original old version from the early offering but I managed to drop it and fracture most of the support plastic mounting. I set it aside and bought the new one when it appeared and it is not the same performance at least on mine. dtvmcdonald is chasing his new version also here.

Mine suffers from a sync (read speed) control that is running too fast. I can see sync trying to work but the speed is too fast and the control is out of range like your old H control just short of lock. I went back to my old unit and pieced it back together and it still works with full control. The control is even narrow enough to move the onboard test chart up and down for viewing framing. And by ear, it is running much slower than the new. It is hard to get pics of it so stay tuned as I figure that out.

[dtvmcdonald]

I got the CD ripped to 320K MP3s and can now see the waveforms
as generated using Audacity. I can also change the speed.

There are two copies of each short movie except 1 and 18,
the second ones being inverted waveform and you add 17 to the
track number. Using my computer the 1st set are correct.

At least most of them sync much of the time. It also helps
to change the audio volume from the computer.

However, it appears that the vertical (line) sync is exactly
off phase: the bottom and top of the picture and the black bar between
are right in the middle. I don't think this can be fixed without a new paper disk to glue in a different orientation.

I found that pushing the disk closer to the circuit board (and thus
the paper sync disk with black and white areas closer to the sync LED and detector) makes it work better,
but still not good enough. I can't make it closer as it would scrape the screw heads holding the LED and
screen. I will try to get some flatter screws.

[dtvmcdonald]

Dave A ... I forgot to ask: how well does your old one work?

Does it sync on all (or almost all or almost half) of the ones on the CD?

How long does it take to sync? Especially on the first few ones that
have the numbered countdown.

Is the image centered in the window? Mine is almost exactly with the
vertical blanking in the middle.

[Dave A]

Doug, I glued my old display back together with the old unit and it is working. The onboard test card is quite bright and stable and the sync(speed) control has enough room at the low end of its speed to fine tune the V framing to center it.

Then I went to the CD and it was mostly good and your note about audio level makes all the difference. I think it could use more gain to the unit. It was about 60% brightness at best. Could Audacity or same be used to increase the gain? Each new track took 3-5 seconds to catch up and I can see the countdown and the portrait head shots with a bit of V wobble. It also seems to video AGC a bit as the first few frames are bright then it drops to the 60%. I could not get exact frame centering but more gain might help that. It is definitly running slower than the new one and has the range needed for some frame centering. I tried photos but that was a fail.

[dtvmcdonald]

I changed the Frame Phase on the Aurora from 1 to 32. This moves the "reference output" transition one line earlier. The "reference output" itself is not used!

The effect is instantaneous: the sync control now adjusts the phase of
the horizontal blanking (i.e. the frame).
Its stable. Changing scenes or channels (this Televisor has a remote!)
doe not cause sync loss.

And even more amazing: on most channels the itsy 30@12.5p TV has actual entertainment value. Football is of course hopeless, but any show that is
mostly closeups or even waist-up shots is watchable. Cartoons are almost always fine.

Amazing!

All I need now is to make my own RGB amplifiers and make a three LED light board.

[Dave A]

Doug, congrats. You are well ahead of me with the Aurora. I just have the factory setup and trying to get sync from that with help here. Old works, new does not. I'll keep trying the CD's et al. and maybe some audio improvements here. The new needs work and advice. A remote? What are you using that is not the science kit?

[dtvmcdonald]

What am I using other than th Televisor? A cheap ATSC to NTSC converter box (with remote) and the Aurora.. And my stereo (connected to the NTSC box) for sound.
Doug

[Pio1980]

This is the coolest thing since the Wild Planet Radio DJ AM broadcast transmitter!
Pity that, like the Radio DJ, it's OOP.

[Electronic M]

Originally Posted by Pio1980

This is the coolest thing since the Wild Planet Radio DJ AM broadcast transmitter!
Pity that, like the Radio DJ, it's OOP.

I really dug that toy as a kid. I was really ticked when we couldn't find it in the boxes after the first move (along with a 4" 1964 Sony TV I had thrifted) a move later the Sony turned up, but 20 years later that radio DJ is still missing...I eventually found another at the thrifts.

[dtvmcdonald]

I got the gizmo working in color, with signals from my Aurora.

See the discussion and images in the British NBTV forum:

https://www.taswegian.com/NBTV/forum...php?f=1&t=3318

I'll post one picture here: the usual Dorothy. Note that the bottom of the picture is the bottom of her blue dress. It repeated at the top of the image, and the bottom of the picture is repeated at the top. The separator between pictures
is the green-magenta-red wavy line.

Of course this isn't the color forum, but this gizmo started out as black-and-red.
The original red LED is removed.

[old_tv_nut]

Nice!

[dtvmcdonald]

I thought that my batteries just must have been getting low, but it was still working fine. So I measured them and the sum of the four was 5.1 volts.
When new they are 6.65. Amazing that the batteries are lasting so long.

[dtvmcdonald]

Oh yes ... does anybody know where I can get a premade 7" disk for this thing thats actually flat. Like T-6061 aluminum or epoxy-fiberglass.

One could of course have one made to order by computer controlled milling
or spark erosion cutting if a suitable metal.

Doug McDonald