I removed the low level probe. LED2 still comes on with transmitter. Does not with manual.

I'm working off of this diagram. There is no R7, you must have meant R3. Reduced it from 100k to 33k. Problem does nt change.

 

R7 is on a later design, post #124.
Leave R3 at 100K but R7 from the base to ground at 33K on Q2.

 

I do not have any LM393's. That would complicate the PCB design.

Thought I would try the scope (which I'm not entirely sure how to use yet). The output at the junction of D4/D5 is 5 volts with the momentary switch and is 7 volts with the transmitter switch. Would this make any difference?

 

Just about to ask using the scope.
Not really as the servo is powered by the 7.2 volt battery.
Put the scope on terminal #2 on the low level electrode with the servo ON.
Did you try R7 at 33K?

 

I cannot do the circuit in #124. Do not the parts.

Just want to be clear. It is not a servo. It should not matter, this device (Electronic switch), is plugged into the receiver and turns on and off when the transmitter is toggled to turn it on and off. The receiver is powered by it's own 5v source. The bilge pump circuit is powered by a separate source (8v). The electronic switch is acting as a relay kinda. It gets power from one lead 3-30v and outputs in this case 7v to the load. In this case the source is the same 8v.

 

Yes, I understand the "servo" is just an electronic switch.
Did you get scope image on terminal #2 of the low level probe?

 

Hold on. Working on it. Something happened, trying to fix it.

 

Not sure what happened. I'm back to the below circuit.

When low probe is in the water, LED2 on, pump off.
Put upper probe in, LED3 comes on but there is a 5-10 second delay for the pump to come on. Did not do this before, pump always came on immediately. AND, when upper probe is removed, the pump goes off, it should not go off until lower probe is removed.

With probes out of water, activated 'servo', LED goes on, see the scope pic, measures 7.6 volts on the meter.

Still trying to figure out what is messed up.

 

Replace D4, don't bother testing it just replace.

 

Done.

Still same problem.

 

Then something is definitely wired wrong.
Need to double check the connections.
Does the relay and motor activate immediately when manual is pressed and using the transmitter?

 

Yes pump/relay activate immediately with manual and transmitter. And LED2 goes on with transmitter only.

Continue to check everything

 

Will continue working on it. Have other things to attend to. Will be back on this tomorrow.
Thanks for the help and sticking with me.

 

When you have time.
I see on your breadboard a red wire that appears on one end connected to pin8 of the relay.
What is this wire and what is connected on the other end?

 

BINGO!!!!

Good eye!! That was the problem!! That wire is the signal coming from the electronic switch. I had it connected directly to pin 4 when it should have been connected to the junction of D4/D5. LED2 now is off when SW1 or SW2 is active. And the pump comes on immediately.

Now to figure out the problem when the probes are inserted and the pump delay. LED2/3 come on when they are supposed to but there is the 5-10 delay for the pump to turn on.