Ripweade
Active member
Quick background. My breathalyzer isn't working right. When I turn it on, it can detect alcohol pretty good. But, as it stays on, it doesn't detect a thing. In other words, it seems to slowly stop registering the longer it's plugged in. I just bought a new sensor and plugged that in, but no difference.
I was originally thinking that it could be a leaky cap on the board, but not too sure now. I individually bridged three of the four on the main PCB with good caps and no difference. There is a huge 10000uf cap on there which I don't have, so I didn't test that.
I tested the power supply, and it's outputting 5vdc fine. I didn't check under load, but at difference spots on the main PCB, I was getting a 5vdc reading, so I am assuming the power supply is fine.
Everything else is working except for registering alcohol in the sensor. Last week, I did have to reflow solder to an LED lead because the solder joint came loose.
My question: What could cause a machine to work fine when initially turned on, and then slowly stops registering the longer it's on? Could this be more bad solder joints that are breaking contact somewhere when the machine warms up? I'd think not since heat expands, but I could be wrong.
Any teachings in electronics here is appreciated.
Thanks in advance!!!
Bill
I was originally thinking that it could be a leaky cap on the board, but not too sure now. I individually bridged three of the four on the main PCB with good caps and no difference. There is a huge 10000uf cap on there which I don't have, so I didn't test that.
I tested the power supply, and it's outputting 5vdc fine. I didn't check under load, but at difference spots on the main PCB, I was getting a 5vdc reading, so I am assuming the power supply is fine.
Everything else is working except for registering alcohol in the sensor. Last week, I did have to reflow solder to an LED lead because the solder joint came loose.
My question: What could cause a machine to work fine when initially turned on, and then slowly stops registering the longer it's on? Could this be more bad solder joints that are breaking contact somewhere when the machine warms up? I'd think not since heat expands, but I could be wrong.
Any teachings in electronics here is appreciated.
Thanks in advance!!!
Bill


