Falcon MD20

[Matt_Rowe]

Does anyone who built this newest version, the 20, sell the pcb and compnoents as a kit, i called Falcon since they live in my city, they said the md8 would pick up about 1 inch in soil, the MD10 2 inches, and MD20, 3 inches. The only difference in 10 and 20 is depth.

[idigit]

calling Falcon .. sometimes if u repeat call 'they get your number' - like i had one unit , then i got another unit ..
called about the 2nd unit, woman picks up says 'call back in 30 minutes' .. call in 30 minutes and get answering machine ..

[sunita.pradhan]

Can somebody guide me with the correct schematics for a workable falcon. my ferrite coil is 150mH & 1 ohm resistance. I am using 2N2222 transistors with NE555. Continuous vibrating sound is coming from output of 555 but nothing seems working.. can somebody help?

[kt315]

Can somebody guide me with the correct schematics for a workable falcon. my ferrite coil is 150mH & 1 ohm resistance. I am using 2N2222 transistors with NE555. Continuous vibrating sound is coming from output of 555 but nothing seems working.. can somebody help?

FALCON has a specific tuning on threshold. by copper ring on a housing you move it along and tune on sound.
you have to know sure this fact BEFORE to copy the detector.

[haydarpasha]

I WANT TO STATE FIRST THAT I HAVE NOTHING TO DO WITH ELECTRONICS.
I AM INTERESTED IN MINERAL STONES AND I LIKE FALCON SERIES TRACKERS. BUT I DO NOT HAVE THE POSSIBILITY TO PROVIDE IT IN MY REGION. THAT'S WHY I RESEARCHED AND FOUND GEOTECH1 AND THIS FORUM. I REVIEWED THE POSTS ON THE TOPIC.
FIRST OF all, I would like to express my RESPECT TO EVERYONE WHO CONTRIBUTED, INCLUDING ALTRA, DBANNER, GOATY. I SUPERPOSED THE 3 PCB IMAGES FOUND IN THE FORUM. PCB (DIY), PCB (WALKMAN) AND PCB (MD20 ORIGINAL). I ADDRESSED THE THREE PCBS WITH THE SAME NUMBERS. I JUST FOUND THESE DIFFERENCES.
1) IN PCB (DIY) STUDY, THE CONNECTION BETWEEN C5 (92) AND (19),
2) IN PCB (WALKMAN) STUDY, CONNECTION BETWEEN C5(92) AND (19),
3) IN PCB (WALKMAN) STUDY, CONNECTION BETWEEN Q2(87) AND C8(23),
4) IN PCB(WALKMAN) STUDY, CONNECTION BETWEEN BAT1+(36) AND 555(55),
5) IN THESE TWO STUDIES, SENSIVITY CONNECTION WITH (1, (19), (20) ENDS,
6) IN THESE TWO STUDIES, GND-BAL CONNECTION WITH (29), (30) TERMS
AGAIN, WHEN THE ORIGINAL PCB (MD20 ORIGINAL) IMAGE AVAILABLE ON THE PLATFORM IS ADDRESSED, IT IS OBSERVED THAT THE ABOVE ISSUES ARE DIFFERENT.
I NEED EVALUATIONS ON THE ISSUES I MENTIONED ABOVE IN ORDER TO CONCLUDE.
HAVE A GOOD DAY TO EVERYONE. KIND REGARDS

[Qiaozhi]

According to forum etiquette, posting in all capital letters is equivalent to SHOUTING.
It also makes the post difficult to read.

[jtz54]

Been following this thread off and on for years. There are certainly some knowledgeable people on this forum! Can anyone provide a circuit theory of operation for the MD20 as it stands today? I think that would help a lot in understanding where possible improvements can be made.

Thanks!

[Teleno]

Been following this thread off and on for years. There are certainly some knowledgeable people on this forum! Can anyone provide a circuit theory of operation for the MD20 as it stands today? I think that would help a lot in understanding where possible improvements can be made.

Thanks!

It's a Colpitts oscillator, the amplitude changes depending on the magnetic coupling to the target. The sine wave is rectified to produce a dc level and modulate the audio signal. The frequency changes too but that variabke isn't used.

[Carl-NC]

It's a classic "energy theft" design, covered in Ch 9 of ITMD3.