Great explanation!

 

I just noticed something. It looks like the switch is using a 555 to tell something else to turn on! So if you can trace the output of the 555, you might be able to simply bypass the whole thing.

 

Can you take a photo top down of the whole board? Maybe something is visible that would help.

 

Nice spotted!

Here's some pictures, don't know if the resolution is good enough.

 

Can you get a shot of the back of the board the switch is mounted to?

 

And one more thing, can you get a clear shot of this area of the board?

 

Here it is

 

 

I assume the board is not easily removed from that case. A view of the underside would be very helpful. I can see the 555 circuit and the power supply section but it is not clear how they are latching the power on.

Perhaps someone else can spot it. That 10-lead package appears to be a TPS4021 boost converter and so it might be they are switching the Vdd on that, but the traces are hard to see and there is at least one more layer on the board if not more.

None of this stops you from creating a 555 circuit of your own to solve the problem, it just might be there is something easier, but I can't tell yet.

You could go ahead and try to wire up the 555 one shot just to learn and get it running in the mean time. You can put an LED on the output and see it work. The schematics are going to have switches on them, but you won't be using one, still, experimenting with the switch in place could be helpful for learning.

 

No unfortunately it's stuck. Thank you for trying, I understand that it's hard to see but maybe someone can, we'll wait and see.

I'm also waiting to see if maybe Eric or someone else will post some kind of circuit.

I have ordered a 555, so I'll have to wait for it to come but then I will try and see if I can experiment a bit.

 

No unfortunately it's stuck. Thank you for trying, I understand that it's hard to see but maybe someone can, we'll wait and see.

I'm also waiting to see if maybe Eric or someone else will post some kind of circuit.

I have ordered a 555, so I'll have to wait for it to come but then I will try and see if I can experiment a bit.

Just a hint. When you are ordering parts like that, never order only one. Occasionally parts are defective when you receive them (particularly in the current market where people sell counterfeits and rejects as genuine), but very often a small mistake ”lets out the magic smoke” and once that smoke is out the part just can’t work.

For expensive parts getting extras can be impractical but for ”jelly bean” parts, like the 555, having extras on hand is useful even if you don’t toast one learning to use them.

 

I changed my mind and decided to use an Op-Amp instead.
Almost any Dual-Op-Amp will work,
but I would suggest the cheap Rail to Rail version in the Schematic.

The Opto-FET in the Schematic is kinda pricey, at ~$6.oo,
but it's a much better solution than a Relay.

The original Push-Button will still work as normal if You happen to want to turn-Off the Amp.
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Thanks a lot @LowQCab!

So from what I can tell in your circuit you don't use the 555 timer? Only a Dual OP-amp and an Opto-FET?

 

And I've tried to search for the Opto-FET you suggested but can't really find it online?

How many pins should that one have? 4?

 

I didn't ask if You were in the US, but DigiKey has plenty of both parts.

If You enter the number exactly as in the Schematic it will pop right up.
https://www.digikey.com/en/products/detail/galco-industrial-electronics/H11F1M/15657740
Same with the Op-Amp ........
https://www.digikey.com/en/products...A4AuUIAyuwE4BLAHYBzEAF9xhAExkQAWQDCABRjSqzcUA

The Op-Amp is easier for me to model than a 555, and it turned out dead simple,
all but one of the Resistors are the same common value, plus 2- 10uf Capacitors,
makes timing adjustments a breeze.

If the time needs to be longer, the formula is roughly ~0.35-seconds per 47K Resistor,
just add more Resistors for more time.
The left-hand-side Resistors are for the "wait-time",
and the right-hand-side Resistors are the "pulse-time".
This will vary to some unknown degree if You decide to use a different Op-Amp.
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No sorry, I'm not in the US, so maybe that's why I can't really find it.

Is it this one with 6 pins?

https://www.digikey.se/en/products/...edium=aggregator&curr=usd&utm_source=octopart

How do I then connect all of the six pins? Two of them goes to the push button and one of them to the 180R and one of them to the 47K. The other two?

So can I use the OP-amp you suggested instead of the 555 timer? Would it work almost the same?

The OP-amp seems easy to find for me!

 

That is the recommended Op-Amp.
It has an 8-Pin PDIP ( plastic dual inline package ) Package.
Look in the description for the Data-Sheet-Link

It sounds like You are talking about the "Opto-FET".
That's interesting, DigiKey doesn't have a Link for the Data-Sheet on this part.

Here it is ...................
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yes I do talk about the Opto-FET, sorry, attached the wrong link.
But I think I found the correct one now, thank you!

I still don't get how to connect the 6 pins though? According to your drawing I can't figure out how.

 

Look at the Spec-Sheet, it gives drawings and all sorts of information.

The Opto-FET is basically an LED, than shines Light on a special Field-Effect-Transistor.
The FET basically acts like an isolated-Switch, and that's why I chose it, it makes things simple.

The Op-Amp turns on the LED through a Current limiting Resistor, just like any other LED,
and then the Opto-FET completes the Circuit at the Push-Button-Terminals.
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Yes, I have been looking and was wondering what to do with pin 3 and 5?

The other ones I think I know where to solder.

Thank you for explaining for me!