When I apply the 12v needed to power the circuit, the alarm stays on.
I relize that the alarm should beep once to allow the user to know that the system is operational, but the buzzer stays on for as long as I have power applied to it.
I eventually made one small adjustment to the circuit and replaced the buzzer with an LED to keep the noise down, but the problem still persists.
I’ve gone thru the circuit board many times making sure that all the diodes and capacitors were properly biased and I have taken a magnifying glass to make sure there were not any solder bridges.
The only part(s) that I am unsure of are the transducer and reciever. On the printed board there are + and - markings. Not seeing any similar markings on the transducer/reciever, I had assumed that the negative lead was the lead that was attched to the case. The + lead, I had thought, would be the lead that was isolated from ground.
After trying the transducer/reciever in both ways I am at a loss as to why the kit does not work. The only other variable that I have not accounted for is the line capacitance that might generate on the wire that connects the two boards together.
As I was going back thru the board, I thought to measure the continuity of the transducer/reciever. After applying the probes to each end I relized that there was no continuity, or at the least the resistance was high enough to read as uncontinuitous.
So I searched across the far reaches of the internet for a data sheet of sort for the components MA40A5S and MA40A5R. You would be suprised at how little I found. Other then the basic information provided on that “part lookup” at Velleman.com that tells the op temp and op freq, there was nothing.
I was wondering if you might know the internal resistance of either of tho’s two parts. The multimeter I am currently using only goes up to 20M ohms. Which I would doubt that the transducer would exceed that.
Also, it would be helpful if you could tell me if I am supposed to be getting continuity thru the component. I would be very suprised if it was capacitive and offered no path for current to flow thru. But I will hook it up to a Z meter to see.
I just relized that the transducer is more then likely a piazo crystal transducer so there wouldn’t be any continuity as it would operate like a capacitor.
argh :x
And I was hoping that it was a bad part.
Nonetheless, if you have any information on the transducer/reciever (other then what is provided on the ordering parts screen) it would greatly appreciate the information.
Well, at long last I had finally found the source of my problem
There is a jumper wire, no more then 5mm in length that is hidden inbetween two chips. When I looked over the board in the past I had always assumed that these holes where part of the variable length capacitor bores.