G'day all.
Back in 2017 I built a 32 line LP record disc synchronized televisor though never shared it at the time as it was for a secret ham radio club project. Anyhow I built the televisor using the NBTVA handbook circuits http://www.nbtv.wyenet.co.uk/beginners.htm . The set worked and did sync up though needed some coaxing and when playing motion videos did go off sync but still pictures and webcam without movement of the camera it stayed locked in sync. The record was of course hand drilled and accuracy of hole position was of course bad resulting in a cruddy crooked picture with unevenly spaced lines.
Fast forward to 2022 and I decided to order some manila Nipkow discs from NBTVA club and have converted the set from heavy record disc to light weight manila disc which was pretty straight forward. On firing up the motor spun too fast so I replaced the 10 ohm resistor with a 47 ohm resistor which fixed that issue. I had a variable LM317 power circuit connected to sync LED and motor boards which I had to tweak a bit to make the motor run close to correct speed. Anyhow the sync is semi working as it will occasionally lock onto sync after tweaking the LM317 power circuit but the picture will slowly bob up and down and go off sync after a while but often the picture doesn't sync. And when it syncs the picture is often offset too. Also adjusting RV1 on the motor board which I guess is a speed control or sync control seems to do absolutely nothing.
From memory I copied the circuits from the NBTVA handbook page mostly to the tee but for the opto fork sync system I am not using a TIL100 opto sensor but some sort of photodiode as TIL100s are not available at my local electronics store so I made do with a photodiode, the infrared light should be a LD271. I have taken scope readings from pins 3 (outputted opto sensor signal input), 13 (output to motor circuit) and 14 (sync input) and have photographed them which are attached to this post.
Anyhow I admit despite making mechanical sets since 2012, I am still pretty much a novice with only basic understanding of how the circuits work especially sync circuits and I call upon those more technically minded than me for help with getting this set synchronised. I would like to know what are the possible issues causing my set not to lock into sync? Could it be the positioning of the hole mask? Choice of opto sensor? The motor I'm using? The positioning of the opto fork relative to the LED matrix? Those wondering why I haven't light proofed the opto fork I do test the set in very low light too and it didn't make a difference in how it synced.
Anyhow I've made construction vlogs on this set which can be seen in the playlist link https://www.youtube.com/playlist?list=P ... vl6TkOzrus
Attached below are pics of the televisor and the scope readings