WANTED: VIKING 5D

[Eugene52]

WANTED: VIKING 5D

Ivconic , I am not building this one !!!!!!! I have 3 other projects that I started over a year ago , and I still have not finished , sheeeesh ....... I am so far behind in everything , I have a big un-touched "To Do List" . My other Hobby is a English word called "PROCRASTINATION" ............This year 2009 I Promise I will finish Everything !!!!..............Regards..........Eugene52

[Qiaozhi]

Here is the schematic and the annotated layout.

This design is quite interesting, as it's not immediately obvious how an audio tone is generated in the speaker/headphones. The TX oscillator does not produce a continuous sinewave, but instead generates bursts of oscillation at around 100KHz. The rate at which these bursts are produced is approximately 170pps, and it is this lower frequency that is heard by the user.
In some ways this design is a simplified version of the Heathkit GD-48, which also used a modulated TX oscillator. However, the Viking uses a DD coil, whereas the Heathkit used an omega.
The tuning cap is used to fine tune the phase-relationship between the transmit and receive coils, allowing the discrimination setting to be adjusted. You need to use a non-metallic trimmer, and adjust it so that a large nail is rejected.
These detectors are so cheap to buy, that it's not really worth the effort to build one yourself.
Also, I think there are some capacitors in the search head (not shown in the schematic) that makes it difficult to measure the coil inductances accurately.

[ivconic]

Yes, i saw datasheet already.
There is always some catch!
This project doesn't makes sense if ic cant be obtained, which is the case here, at my country. Pitty.
This is not serious project at all, yet first time i saw its simplicity, i got idea to make it as compact as possible and use it as pinpointer... Pitty...
But this is good idea for those who can find this obsolete ic. Go for it!

[Eugene52]

WANTED: VIKING 5D

CA3094e , It is a very old I.C. , almost as old as me !!! $1.46 each from Digi-Key , It is becoming very rare !! Look for a Substitute soon before it is too late !..............Eugene52

[nakky]

Mini V5 , 3x5cm.Not checked.Grt Nakky.

[kt315]

It is also a non-motion detector.

how Viking works. it is tuned on constant tone (I think this is not good). the tone falls down on ferrous metal and increase up on non-ferrous metal.
be honestly I am very surprising that the schematic is so simple... Viking has good sensitivity, BTW.

[ivconic]

It is so simple....i must make it. But just searched internet. Is there any "human" substitution for that ic? Not possible to find it in local shops...

[Qiaozhi]

I've just back-engineered the schematic, and the coil connections are mixed-up in the last image. I will post the correct schematic later tomorrow, together with an updated PCB.

The coil housing seems to contain two coils for the transmitter circuit (1x TX and 1x feedback) while the third is used by the receiver.
The IC is an OTA (operational transconductance amplifier). It's quite a simple but elegant design, which exhibits very good ferrous rejection. It is also a non-motion detector. These are very popular low-end budget machines with quite good performance.

[ivconic]

What a blast!?
Is that an "detector" ???
Ha,ha,ha.....
Sorry...but i expected some "machine" there, not just a simple whistler!

[kt315]

http://members6.boardhost.com/classicdetector/msg/1230991259.html

[cordius]

yellow variable capacitor is 7-40 pF

ZTX502 = european BC327
ZTX712 = ???
diode will work 1n4148.

[Qiaozhi]

Here's the layout annotated with the component values, and the attached wiring. The TX coil connects between TX and SCREEN. The RX coil is center-tapped, with the tap connected to the screen. The diode looks like a general purpose signal diode, but it is not possible to see the actual value without removing it. The variable cap has no visible markings.

[cordius]

Patrick , Awesome work !!!! I did not know of any Sprint version that could convert from an image to a PCB layout ....What version ???....Please let us know more !!! There are some images on this forum , especially the New up-dated Hammerhead that would be great to have in "Sprint" .LAY FORMAT !!! To me this is Great News , 2009 is starting out very Good , Thank-you again Patrick , and everyone for this new posting of information !!!!!!!..............Regards..........Eugene52

HI eugene52.
I dont write well english but if you see image, you can understand how to procede to design pcb from a photo

[Eugene52]

Amazing !!!!

Patrick , Awesome work !!!! I did not know of any Sprint version that could convert from an image to a PCB layout ....What version ???....Please let us know more !!! There are some images on this forum , especially the New up-dated Hammerhead that would be great to have in "Sprint" .LAY FORMAT !!! To me this is Great News , 2009 is starting out very Good , Thank-you again Patrick , and everyone for this new posting of information !!!!!!!..............Regards..........Eugene52

[cordius]

Patrick thank's very very much!!!!
is possible to identify the values of the component?
Qiaozhi can you post a better photo of component side?