PT2399 issues going from breadboard to PCB

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

I've had this barbaric pt2399 circuit on my breadboard (it works perfectly (for my purpose) on the breadboard) for a while and have been trying to get it to PCB form so I can use it in projects however it never seems to work.

I have mapped it out on Fritzing:

My first attempt, I tried drawing it in on the schematic tab and autorouted. This design had output but it was completely clean, the knobs were basically doing nothing and no delay/effect.

Please see ATTEMPT 1 screenshots of the schematic and the autorouted pcb layout. I coudn't embed an image.

This latest attempt, I routed it on the breadboard tab, basically just following what I see on my breadboard and autorouted. This one I can hear very faintly the delay but the repeats and volume controls are a mess and the circuit is basically useless.

Please see ATTEMPT 2 screenshots of the schematic and the autorouted pcb layout. I couldn't embed an image.

I am not heavily educated on electronics, I just learn online and plug things in and see what happens. I am assuming I am making some classic mistakes, may be to do with how you should assemble components around the pt2399/autorouting not suitable.

Could someone help/shed wisdom?

Thank you.

ATTEMPT 2 - BREADBOARD CIRCUIT PCB LAYOUT.png

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ATTEMPT 1- SCHEMATIC CIRCUIT PCB LAYOUT.png

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ATTEMPT 1- SCHEMATIC CIRCUIT PCB LAYOUT.png

ATTEMPT 2 - BREADBOARD SCREENSHOT.png

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Grumble · Posted: Wed May 31, 2023 7:12 am Post subject:

On both the schematic pictures the 5 volt coming from the regulator isn’t going anywhere but to +pin of the 47uF capacitor.

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

Ahh OK, I'll look into that when I get home, cheers grumble.

As another note, do you think the potentiometers are wired correctly, doing some searching, Fritzing potentiometers might be set up not how they seem. As in lug '3' may be the middle lug, I assumed it was the 3rd one going ---> that way if turning it.

We'd be talking about the schematic version.

Grumble · Posted: Wed May 31, 2023 10:05 am Post subject:

In the drawing named ATTEMPT 2 - BREADBOARD CIRCUIT PCB LAYOUT.png (top drawing) the potmeters are differently drawn as in the lower drawings.
The middle pin of the potmeters are the wiper of the potmeter, between the left and right pin you should measure the total value of the potmeter, regardless of the position of the wiper.
As a sidenote: I can’t imagine why anyone should place a 10uF capacitor in series with a 100nF capacitor… so there is something wrong as well…

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

Riggght OK so the pots are wired wrong then as the potentiometer part I used in the schematic; number '3' is the 'wiper' and not the 3rd lug. I'll figure that but would this be connected OK now for the power?

Would you be able to kindly elaborate on everything that looks wrong so I can troubleshoot?

Thanks

ATTEMPT 1- SCHEMATIC CIRCUIT - updated1.png

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floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

Reuploaded schematic as the default Fritzing values are probably confusing.

I circuit is based on a hand drawn schem I saw on Google so I am sure there are things that are not right.

Thanks

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Grumble · Posted: Wed May 31, 2023 12:00 pm Post subject:

Problem is, I'm not at home and won't be for at least a month, so I'm doing this on my smartphone.
So I hope that another forum membet will chip in...

Steveg · Joined: Apr 23, 2015 Posts: 184 Location: Perth, Australia

Outside my area of experience so I'm not truly able to help. But looking at the circuits here might help: https://sound-au.com/project26a.htm

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

No worries grumble and thanks Steveg for that link, the information on there looks good to compare to. I just got to get stuck into the breadboard but I'm away for the weekend now.

Please, if anyone is able to offer anything else I'd be so grateful.

floating-water · Joined: Oct 06, 2020 Posts: 62 Location: UK

@Grumble, would you be available to run through the circuit now if you are back?

Thanks

The Peasant · Posted: Tue Jul 04, 2023 11:50 am Post subject:

I don't have any experience with the pt2399, but comparing your schematic to the data sheet most of it looks fine now except for the bottom right hand section which has some differences. I suggest that you take a look here: https://datasheet.lcsc.com/lcsc/1806132210_PTC-Princeton-Tech-PT2399_C84963.pdf

Take care,
Doug