Dr Robert Beck

[Algorythm]

Vtech, unfortunately I don't have access to my camera right now, something went wrong and it doesn't seem to co-operate. I changed the batteries with new ones but no luck, I think it has a mechanical malfunction. I did a few tests though and transistors seem to work ok. I'll post a few pictures when I have my camera working again. BUT! The weirdest thing was that I isolated the secondary circuit (your original) from the primary (the 3 4047s alone) and guess what...The 4047s alone draw around 80mA!!! Nothing else connected, just the three of them! Quite strange to say the least...I have to borrow another multimeter to cross check it. Be back later with more tests and results!

[blackchisel97]

Nick, If you can, make a test bed for one 4047. Connect all jumpers between pins but follow the schematic, not the circuit you have built. Get both resistors and cap in place and check the current. It should be in 1-3mA range at most.
There maybe a problem with 4047's too.

Vtech

Assembled BT as per original 556/555 circuit -

[Algorythm]

We have a success ladies and gentlemen! Suspect arrested! Totally my mistake. I was of the false estimation that pin no 7 had to remain unconnected because I saw on the datasheet it was supposed to be connected to Vss. Which I thought it was a different voltage line, like in op-amps, so I left it unconnected. It's not like that, Vss is the GND of the circuit in this occasion, so pin no 7 has to be connected to the ground line. I uploaded a video, in case anyone would like to see what happens when you leave it unconnected. Here it is:

cd4047 error found - YouTube

A big thank you goes to you Vtech, without you noticing it, I would never have figured there was a mistake here! :-)

[blackchisel97]

The culprit always hides in a plain view I'm glad you found it and got it working.

Cheers
Vtech

[Algorythm]

Indeed Vtech! In fact YOU found it, I just fixed it :-) Here is the video of it working:

It works! - YouTube

A final detail though...The output voltage Dr. Beck mentions (that has to be around 2V) is RMS or P-P voltage?

Thanks again my friend for the invaluable help! :-)

[blackchisel97]

Indeed Vtech! In fact YOU found it, I just fixed it :-) Here is the video of it working:

It works! - YouTube

A final detail though...The output voltage Dr. Beck mentions (that has to be around 2V) is RMS or P-P voltage?

Thanks again my friend for the invaluable help! :-)

2V AC (RMS) measured across the 1.3k dummy load. This is to ensure that the output signal can have full range of amplitude. 1.3k simulates skin impedance.
Just curious, what is the total current draw without the load? I want to compare with 556/555 circuit which draws approx. 20mA. You said in the YT 11mA but is this with or without the load? Either way it is much less than 556/555 and the battery will last much longer with this setup. That's what I expected and wanted to try.

Now. The next project I want to try is to modify all seven oscillators in 4 Wave device and replace them with 4047's. We'll get better running circuit, no worries about 50% duty cycle and total current draw reduced by half. I also have a different candidate for op amp. but I need to assemble and check everything myself before suggesting anything. I don't want people to waste their time and money in case if I'm wrong.

Thanks
Vtech

[Algorythm]

It's RMS then,ok! Thanks! Without the load, just the 3 ICs working together, the total current draw is only 1.53mA. This without the rest of the circuit connected, just the oscillators. With the rest of the circuit connected but without the load, it's around 8mA. And with the load, around 11mA.

[blackchisel97]

It's RMS then,ok! Thanks! Without the load, just the 3 ICs working together, the total current draw is only 1.53mA. This without the rest of the circuit connected, just the oscillators. With the rest of the circuit connected but without the load, it's around 8mA. And with the load, around 11mA.

Perfect. Thank you Nick.

Vtech

[sunshiner434]

Sir, please kindly post the BT v2's components and their values list because in the PCB layout I found values of some components was not mentioned.I compared your PCB layout with schematic of Mr.algorythm where he has pointed all the modifications suggested by you in red color posted in page 26 in order find the missing values but didn't matched.Saturday I will have my new multimeter ,so I was hoping if you post the component's values list I can start building BT v2 from where I left it.So please kindly post the component's value list.

And I am very sorry,earlier I said I couldn't see the IC's pin numberes because of the hazyness of the PCB layout but that not true the schematic is alright ,my printer was the problem.

[sunshiner434]

Mr.algorythm you said the pin 7 of 4047 have to be connected to the GND,which line is the GND in the schematic.

[blackchisel97]

Here you go, values of components as I have in four assembled and tuned units -



Parts List:

Transformer - 42TM006-RC (Mouser)
IC - LM556N, LM555N
Trimpots: (vertical) 100k,10k x2
Transistors: 2N3904 x2, 2N3906 x2
Potentiometer - 100kA w/switch
Miniature switches: On-Off-On, On-Off or one switch SP 3 position
Capacitors: 1u tantalum, 0.22u, 0.01u x2
Resistors 0.125W: 1.5M, 56k x2, 22k, 20k, 10k x2, 4.7k x2, 2.2k, 1k, 220R
Diodes: 1N4148 x4, LED 3mm red
Battery connector



Vtech

[Algorythm]

Sunshiner the schematic has been updated, check it.

[sunshiner434]

Thank you thank you very much both of You sir.

[sunshiner434]

Where I will connecte the 9v- in the circuit Mr.blackchisel.

[blackchisel97]

Where I will connecte the 9v- in the circuit Mr.blackchisel.

To the common connection with a "ground" symbol.

Vtech