Tweet
Hello everybody;
I just bought an MD-7020C underwater metal detector. I know they do not have a good reputation and lack in quality. I know a lot of thema do not even survive their first trip underwater. Initial air tests yielded 4-5 inches depth with a US quarter. Since I know this detector is supposed to be based on the fisher 1280X ,I knew I could squeeze more performance out of this cheap Chinese detector. I decided to open the detector in order to tune the trim pots by following the DetectorPro tuning guide, http://www.treasurelinx.com/detectorpro.html. Although in my detector the trimpots were labeled different(RP1,RP2,RP3),I managed to figure out which trimpot corresponds to each function.
I replaced the cheap Chinese trimpots with some quality units with a built-in micro knob and installed them with cable extensions for easier tuning without fully removing the PCB from the housing. Although,I did notice that the discrimination trimpot had very little effect on the quality of the sound of a copper penny at max discrimination, as explained in the tuning guide. Regardless of the position of the trimpot, the sound of the penny changed very little. After tuning, I was able to increase the detection distance of a US quarter from around 4.5 inches to 6.0 or so. I know that a fisher 1280 can reach 8 inches or more on a US quarter, what else can I do?
Lastly the MD-7020c has no volume control,and the audio output is very weak. How can I increase the volume output?
Can I change a resistor in order to increase the audio volume. I am an electronics beginner,so I need some help figuring out which resistor to change and to what value. I will try to upload some images of my PCB for your consideration and review.
I just bought an MD-7020C underwater metal detector. I know they do not have a good reputation and lack in quality. I know a lot of thema do not even survive their first trip underwater. Initial air tests yielded 4-5 inches depth with a US quarter. Since I know this detector is supposed to be based on the fisher 1280X ,I knew I could squeeze more performance out of this cheap Chinese detector. I decided to open the detector in order to tune the trim pots by following the DetectorPro tuning guide, http://www.treasurelinx.com/detectorpro.html. Although in my detector the trimpots were labeled different(RP1,RP2,RP3),I managed to figure out which trimpot corresponds to each function.
I replaced the cheap Chinese trimpots with some quality units with a built-in micro knob and installed them with cable extensions for easier tuning without fully removing the PCB from the housing. Although,I did notice that the discrimination trimpot had very little effect on the quality of the sound of a copper penny at max discrimination, as explained in the tuning guide. Regardless of the position of the trimpot, the sound of the penny changed very little. After tuning, I was able to increase the detection distance of a US quarter from around 4.5 inches to 6.0 or so. I know that a fisher 1280 can reach 8 inches or more on a US quarter, what else can I do?
Lastly the MD-7020c has no volume control,and the audio output is very weak. How can I increase the volume output?
Can I change a resistor in order to increase the audio volume. I am an electronics beginner,so I need some help figuring out which resistor to change and to what value. I will try to upload some images of my PCB for your consideration and review.
Comment