Introduction and Question

[Jeremy S]

My name is Jeremy Schotter and I'm a complete beginner when it comes to NBTV. I have a background in antique radio restoration and amateur radio; you can read about some of my projects on my webpage here: www.radiorestorer.com.

I have wanted to build a mechanical TV for some years now, but other obligations in life (engineering school at Purdue) put most of my projects on hold for a few years. I finally have time to build a TV project, and am doing so for my senior project class at school. I get to kill two birds with one stone! I found a design here to get me started: http://bs.cyty.com/menschen/e-etzold/ar ... ngdisc.htm

For those of you not familiar with that link, Mr. Etzold has done a spectacular job documenting his project and putting videos on youtube. I am going to attempt to build his design, a 32 line B&W television, but have ran into some obstacles with getting started. Per his schematic ( http://bs.cyty.com/menschen/e-etzold/ar ... onitor.gif ), I am trying to determine what a “7812” and “4046” are. Per the write up on that page, I know that the sync pulse is being compared to a reference pulse via the 4046, but I am still unfamiliar with this component. Is the 7812 some kind of DC regulator perhaps?

I am fairly certain that I can identify and order the remaining parts, but mainly was a little lost on the two mentioned above. Any and all help with me getting started will be greatly appreciated!!

Jeremy Schotter
KC9GIC

[M3DVQ]

The 7812 is a 12 volt linear regulator, the 4046 is a 4xxx series CMOS chip. Its function is a phase locked loop

[johnrpm]

Welcome Jeremy,
My advise would be to join the nbtva, the club shop have most if not all the things needed to get you started, pcb's, components etc,
but be warned, this hobby is addictive, once you start you can not seem to stop.

[Harry Dalek]

Hi every thing really to make a simple monitor and above is on the forum ..read and experiment
I would of started as i did with a simple monitor manual motor control via say a lm317....my early monitor used a a pwm kit from jaycar or dick smith this did the motor control manual speed ...and just used a small amp to drive the leds ...wonder they never died but it works.

[Jeremy S]

Thanks for the help so far! I will definitely let you guys know how my project turns out and I will more than likely have more questions for you.

Jeremy

[Jeremy S]

Well, I'm back with an update on my project and more questions on how to proceed from here.

I purchased a 12 inch, 32 line disk from Peter Yantczer. Never could get a hold of Peter by email, but he did answer his phone and was extremely helpful and friendly. I hope to deal with him again in the near future.

I built the circuits in the schematic below. I used a DC motor out of an old 8-track player which seems to do a great job of spinning the disk. The disk is mounted to a hub that I made out of a VCR head.

When I power my TV up without a video signal being inputted but all the circuits fully hooked up, the motor will spin up for a few seconds then shut down. If the video sync pulse is disconnected to the motor driver circuit (4046) with just the output of the opti-fork going to the 4046, then the disk will spin at full speed. The opti-fork pulse is roughly 3Vp, see the attached picture. I am guessing that my motor driver/sync board are working correctly, and that I need a sync pulse from the video input to make it fully work?

I have tried a few sample NBTV files, but my LEDs do not respond and I get no sync pulse out. I did double check my wiring to verify that I have it built correctly. With all of these pots to adjust, what might a good procedure be to get started or to test out my circuits?

I will take some more pictures this weekend of my project to post on here.