4046, the hoary old chestnut

[Viewmaster]

Just been looking at past threads on that old hoary chestnut of NBTV, the 4046pll.
As it's the time of the year for chestnuts thought I would raise it again.

Just over half way down this 3 year old thread........

http://www.taswegian.com/NBTV/forum/vie ... light=4046

a new motor control circuit was shown developed by Klass. ( Motor 2.gif ) There, a 220k damping pot is shown, replacing the 2 fixed 100k Rs. (Motor 1.gif) together with a push switch.

I see in the latest handbook that this new version with the pot is not included and I wondered why?

[Rydepier]

a new motor control circuit was shown developed by Klass. ( Motor 2.gif ) There, a 220k damping pot is shown, replacing the 2 fixed 100k Rs. (Motor 1.gif) together with a push switch.

I have just used this circuit for my televisor. I replaced the push switch with a SPST switch and found this very useful. I am still playing with the sync and set the pot at the centre point. I have not tried adjusting this yet though.

I had to remove the 1M resistor from the 4011 as this simply locked up. The resulting pulse from the output of the 4011 is still a nice square wave peaking at just under 12 volts.

Overall I felt that the modifications introduced by Klass were worth while.

Chris