Please check my PLFO layout

[HighSolstice]

I made this layout and attempted to build it but the pots seem to only change the brightness of the LED to various degrees, the rate knob is definitely not behaving as expected since the LED never blinks.  Please have a look at my layout and let me know if you see what I'm missing.  I based my vero layout off the attached perf layout, the schematic is included as well.

https://effectslayouts.blogspot.com/2019/12/grind-customs-fx-de-profundis-delay.html
https://www.dropbox.com/s/00p7i5809q34d11/PLFO%20-%20Grind%20Customs%20FX.pdf?dl=0



I tried building the one at the following link as well and had the same issue so I was wondering if it might be an issue with my 4558 chip but I'm not sure how to go about confirming this.

https://tagboardeffects.blogspot.com/2014/04/grind-customs-fx-deprofundis-delay.html

[cab42]

I only had time for a very Quick check

I Can”t find the voltage divider in the layout. The 220k from 9v to the noninverting input and the 220k from that to Ground. I Think the one to Ground is missing

Also I count Four 220k”s in the schematic and only three in the layout.

I Think there was a comment on the layout about a missing 220k

[ElectricDruid]

+1 agree - there looks to be something funny with the layout. The comments mention adding an extra resistor to pin 5, which might make sense - what do the little crosses connect to? It's floating otherwise.

How many 220Ks do you have on the board? There are four in the schematic, as far as I can see, but that doesn't include anything on pin 5.

What's that resistor labelled "LDR" on the board?

[cab42]

What's that resistor labelled "LDR" on the board?

I think it is a LDR ( ) to be put together with D1 in shrink wrap as a home made vactrol.

[ElectricDruid]

What's that resistor labelled "LDR" on the board?

I think it is a LDR ( ) to be put together with D1 in shrink wrap as a home made vactrol.

Well, in that case, you're right and there's definitely a 220K missing. I wondered if that might be it, mis-labelled (the labels wander about all over the place, apparently).

[HighSolstice]

I've updated the layout and added an extra row for the 220k to ground.  I haven't built it yet but will give it a shot soon.  I intend to add this to a Disaster Transport Jr that I recently built, seems like this mod board can be easily added to most PT2399 based pedals.  It looks to me like the crosses in the schematic represent pins 1-3 of the Wave pot, I believe it's depicted that way on the schematic because it can be optionally wired as an SPST switch with Sine and Square Wave or a potentiometer which blends between the two.

[cab42]

I've updated the layout and added an extra row for the 220k to ground.  I haven't built it yet but will give it a shot soon.  I intend to add this to a Disaster Transport Jr that I recently built, seems like this mod board can be easily added to most PT2399 based pedals.  It looks to me like the crosses in the schematic represent pins 1-3 of the Wave pot, I believe it's depicted that way on the schematic because it can be optionally wired as an SPST switch with Sine and Square Wave or a potentiometer which blends between the two.

Shouldn't the rightmost 220K (B13 to F13) go to the inverting input of the opamp (pin 6 in row G)?

[HighSolstice]

Good catch, it looks like you're correct.  How's this look?  I removed the cut in row G.

[cab42]

I don't think you should have removed the cut. Add another column for the cut. As it is now the 3330R is connected to the input of the amp, which it shouldn't.

Otherwise it looks OK ( I think)

A tip for troubleshooting veros: Go through the nodes in the schematic. Normally I start at the input of the circuit, but as we don't have one here I started with the non-inverting input on IC1A. I can then see that this should be connected to three 220K's and a switch. That was how I caught the first error. It was only connected to two 220K's in the vero. Using the same approach, I check all the nodes in the schematic to see if components are connected to what it should. That was also how I found the last error. I could see that the inverting input should be connected to a 220K and a 10n but in the vero it was also connected to the 330R and depth 1

[HighSolstice]

Oops, I've updated the layout again.

[HighSolstice]

Built and verified!

[cab42]

Built and verified!

Cool. I might look into it myself. Not very far down in my build list I have a PT2399 delay (Haven't decided which yet)