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

[W2HX]

I believe the light from the LED functions as the “current source” to the base of the transistor. I think pin 6 is there in case you want to override the input from the LED.
Eugene


From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of Steve Garrison
Sent: Wednesday, December 9, 2020 5:54 AM
To: Gerry Block <gblock at sbcglobal.net>
Cc: N4TTY at ARRL.NET; Greenkeys <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] Jack (K2TTY/K0TTY) Hart's Motor Control Board

Yes, I have finally come to grips with the issue I was having with what I was seeing on the opto-isolator.  And Nick, K4NYW, sent me some scans of the top and bottom of a bare board so that I could confirm the fact that there was no connection to pin 6 of the H11D1.  Have only used Jack's board an not having done any design work with an opto-isolator, I would have thought there would have had to have been a connection to pin 6.  Without a board handy to refer to, I was assuming (I know!) that the board would have a connection and that there was an error on the schematic that had remained undiscovered all these years.  I guess my breakfast this morning could be the egg on my face! 🙂

Not having a bare board for a project in mind, I had the bright idea of trying to improve my Kicad skills and recreate Jack's board in a 2020 edition, or 2021 if I don't get busy.  With full credit to Jack for his design right on the board silkscreen.

Anyone interested if I'm successful?
Steve G./N4TTY
Sent from my iPhone

On Dec 8, 2020, at 9:08 PM, Gerry Block <gblock at sbcglobal.net<mailto:gblock at sbcglobal.net>> wrote:
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<mailto: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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