[GreenKeys] Jack (K2TTY/K0TTY) Hart's Motor Control Board

[Gerry Block]

 Steve,
It looks correct to me.
When the loop is high 2N4126 is turned OFF (It is pnp) and 555-2 is HIGH.  This is the timer-running condition.  If left in this condition, 555 will 'time out' and turn off pin 3 (motor relay) after delay period.On receipt of a spacing condition pin 555-2 goes low, triggering the output relay (pin 3) to turn ON, and resetting the timeout period by shorting 10uF cap.
Also, knowing Jack, he wouldn't publish a schematic with a mistake.  
Gerry AD6MC
    On Tuesday, December 8, 2020, 03:20:31 PM PST, Steve Garrison <steve.n4tty at gmail.com> wrote:  
 
 
How many of you have used this board?  I’ve used a few of them, but none of them are readily accessible at the moment and I have a question about the schematic.  I thought I still had a bare circuit board around here, but I can’t seem to locate it.  

  

If I could find the bare board I could try to resolve an issue with what I’m seeing on his schematic.  I’ve attached his schematic and wondering if some of you could put your thinking caps on and help me figure out if what is on the schematic is correct or wrong.  It has to do with the opto-isolator (H11D1) pins 4, 5, & 6 and how they are connected.  It just looks wrong to me.  Trying to see if it is just a mistake on the schematic, but the board itself must be right as I have several buried in working installations.

  

Steve G./N4TTY

  
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