Pins 3 and 5 are NC (Not Connected)
There are no bonding wires from the die where the electronics are to the pins. They are just there for mechanical reasons.

 

I cannot offer technical assistance other than to say:

- Consider placing your project on hold and take some time to learn basic theory, this site alone has has an extensive learning section where many of your questions will be answered with study.

- Have you tried reverting (undoing) all of your modifications to see if the device operates normally? It's possible you may have caused damage to one or more components.

- Don't throw good money after bad, mistakes happen (both in purchasing the wrong product and making modifications) so don't be discouraged if your device ends up in the junk bin.

I make these recommendations because it seems to me you are going on ahead without a foundation in theory. In my early days of electronics I would connect this to that and hope for the best in many cases (just to see the effects). Only later did I realize that I was setting myself up for further hardships in understanding plus many of those components are now compromised because I subjected them to conditions outside of their specification. However if you are just trying to get this device rolling and then move on with your life, I say soldier on!

 

Thank you @Yaakov, that was what I thought!

Good point @k1ng 1337, I'm really trying to learn the basics, but it is also good for me to learn by doing.

I have tried to undo everything and checked that it is working just like before, so I think it should be fine!

At least I have ordered everything now and hopefully it will work somehow, but I expect to run into problems when I try to connect everything. But I will try, I really want it to work.

I have a question in the mean time (I have been trying to search and read about it, but can't really find anything). I understand @Yaakov description, but what I don't understand is that my amplifier is on for about 8 seconds and then off for maybe 1 second. But I just need to push my button very fast to turn my amplifier off.
Why would the amplifier be set to go back to open mode after 8 seconds? Is it the 555 timer we saw on my images that is controlling this behaviour?

About the circuit that I'm now trying to build: would it send pulses so that my amplifier wont think it needs to go into open mode and stays in closed mode all the time?

 

Thank you @Yaakov, that was what I thought!

Good point @k1ng 1337, I'm really trying to learn the basics, but it is also good for me to learn by doing.

I have tried to undo everything and checked that it is working just like before, so I think it should be fine!

At least I have ordered everything now and hopefully it will work somehow, but I expect to run into problems when I try to connect everything. But I will try, I really want it to work.

I have a question in the mean time (I have been trying to search and read about it, but can't really find anything). I understand @Yaakov description, but what I don't understand is that my amplifier is on for about 8 seconds and then off for maybe 1 second. But I just need to push my button very fast to turn my amplifier off.
Why would the amplifier be set to go back to open mode after 8 seconds? Is it the 555 timer we saw on my images that is controlling this behaviour?

About the circuit that I'm now trying to build: would it send pulses so that my amplifier wont think it needs to go into open mode and stays in closed mode all the time?

In normal operation you release the button before pressing it again. What happens if you start with the amplifier off, then hold down the button for more than the 8 seconds? Also, if you start from off, turn it on, and immediately try to turn it off again, does it behave the same way as if there was a gap between the two operations?

The behaviof depends on how exactly they implemented the switching circuit.

 

If I hold the button after starting the amplifier it starts to behave exactly as when I soldered the wire between the poles, turning itself on and off.

If I immediately try to turn it off it doesn't work, I have to push a few time (or wait like 2-3 sec) before it turns off.

Will this work with the circuit @LowQCab posted?

 

My Circuit only provides the equivalent of 1-short Button-Press right after Power is applied to the Amp.
It does nothing else.
.
.
.

 

If I hold the button after starting the amplifier it starts to behave exactly as when I soldered the wire between the poles, turning itself on and off.

If I immediately try to turn it off it doesn't work, I have to push a few time (or wait like 2-3 sec) before it turns off.

Will this work with the circuit @LowQCab posted?

So you can see your shorting link was just like the button, and the fact you have to wait shows that there is probably a discharging capacitor involved.

The circuit you are going to use will behave like one switch press, and so it is also like just pressing the button to turn it on,.

 

Okay, so the circuit will simulate 1-short button-press to make the amplifier "think" it is on even though the button wasn't pressed?
And since it then "think" it's a closed circuit it won't turn off after a while?
Just trying to understand

 

Okay, so the circuit will simulate 1-short button-press to make the amplifier "think" it is on even though the button wasn't pressed?
And since it then "think" it's a closed circuit it won't turn off after a while?
Just trying to understand

Here's what's happening:

The switch on the amplifier is a simple normally open (NO) momentary contact switch. The NO part means that when the switch is not being activated it's terminals are isolated from each other and no current can flow.

When the switch is operated (pressing the power button) the terminals are bridged with a conducting element. Some piece of metal is connected from one terminal to another by the action of pushing on the switch's actuator which is the part presented to be pressed on by the user.

This bridging is exactly like your shorting link, it closes a circuit in the amplifier and allows current to flow in it. In this case, it appears to be connected to a 555 IC, which is probably wired as a bistable meaning it latches on and off.

This would normally be done with two switches but can also easily be done with one, as in your case. The 555's output then goes high turning on a transistor that allows current to flow from the USB power input to the amplifier's power supply circuit.

You would do exactly what the switch is doing if you took a wire and bridged the terminals for just long enough to power it up, then removed it, which is just what happens when you stop pressing the button and the terminals are once again isolated When you leave the wire in place, you are doing exactly the same thing as holding down the button forever which results in the undesired behavior of the on-off cycling.

The switch is just a much more convenient way to make (close) and break (open) that circuit.

To power off, the circuit is closed again, and the 555 resets so its output pin goes low, turning off the transistor and removing power from the amplifier circuitry. If this doesn't happen, the amplifier will not turn off.

@LowQCab's circuit is also the same as the switch in that the optoFET's transistor closes the circuit when on, and opens it when off. The other part of the circuit operates the LED in the optoFET which is connected to the opamp in such a way as to turn on for a fixed time when power is applied, then turn off and not light again.

So long as the FET is not being turned on, it is off, just like the switch when you stop pressing, so the amplifier will remain on. It is in the same condition as an unmodified version with the button has been pressed to turn it on.

The key is to recognize that the switch, your shorting link, and the optoFET are all functionally identical in the circuit. The difference with your shorting link is that it never turns off, and so the 555 bistable resets after a while and the cycling begins.

[EDIT: touch ups due to proofreading post-posting without content change.]

 

Now I understand perfectly! And also why LowQCabs circuit hopefully would work.
Thank you, once again great explanation!

 

Just for interest, @LowQCab, what program are you using for simulation and circuit build?

 

Just for interest, @LowQCab, what program are you using for simulation and circuit build?

It's a very cheezy Freeware-Program called "Ideal-Circuit".
I don't particularly recommend it, it's loaded with glitches, and idiosyncrasies.

One of these days I may get around to learning something more sophisticated like "LTSpice",
but, oddly enough,
there are plenty of people who actually praise Ideal-Circuit,
but in my opinion, I still think it's pretty lame.
.
.
.

 

Long time no see, but I just wanted to check in and tell you that the circuit @LowQCab posted works fine.

Many thanks to you and to @Yaakov who helped me a lot. I really apprechiate it! Keep on doing your good work here at the forum.

 

Long time no see, but I just wanted to check in and tell you that the circuit @LowQCab posted works fine.

Many thanks to you and to @Yaakov who helped me a lot. I really apprechiate it! Keep on doing your good work here at the forum.

That’s great to hear. It was certainly an opportunity to learn new things. Do you plan o pursuing more electronics projects?

 

Yes, I believe so, I think it's fun and the best way to learn is by doing it yourself. I would also like to be able to draw my own circuits, like LowQCab did for me. But that would have to be in the future. Thank you!