# No modulation in Sea Horse



## Jonathan (Aug 25, 2019)

I'm getting clean sound and some slap back delay from the circuit and when I turn Dim all the way up it oscillates but no modulation. I hear a faint modulation while  I turn the depth knob but once I stop the modulation stops. I reflowed the solder on the pots 3 times, any idea what's going wrong?


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## SteveScott (Aug 27, 2019)

I am by no means the greatest troubleshooter yet, but I'd be happy to look at a picture to see if anything stands out to me.


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## zgrav (Aug 27, 2019)

Just about any request for assistance is easier to reply to if you post good pictures of both sides of the PCB.


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## Jonathan (Aug 28, 2019)

Sorry for the delay in pictures, I meant to add them the next morning I just got a little caught up. I know the solder joint on one of the b25k pots doesn't look great but I'm sure that was good at some point, I've taken it out and redone it several times, making sure to bend the wire and lay it over the side so it's contacting the pad. I'll try going over that connection again tomorrow. Also the 9v wire broke off during my last test but I was getting 9volts up until then. 



https://imgur.com/a/yyWl9Y3


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## DGWVI (Aug 28, 2019)

Do you have another PT2399 to try? I've had a few of them give out in builds before. No modulation or delay was usually the symptom


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## Jonathan (Aug 28, 2019)

DGWVI said:


> Do you have another PT2399 to try? I've had a few of them give out in builds before. No modulation or delay was usually the symptom


Yeah already tried a couple. I think they're from the same seller tho. I'll pull one out of my clarinot tonight to be sure.


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## chongmagic (Aug 28, 2019)

Have you checked any of the voltages with a DMM? You can at least determine if the PT2399 is getting the correct voltages. You should be getting close to +5v on pin 1.

You also probably want to reflow the solder joints some look a little iffy.


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## SteveScott (Aug 28, 2019)

Your connections to your pots could be cleaner.  Definitely reflow your solder on the depth pot and trim excess wire.  But as chongmagic stated, you could stand to go over the whole thing and clean it up a bit.  You may find this helpful; I did.   



  And in the future, you may want to stick to pcb mounted pots.  It makes things much cleaner, and easier.  You just have to stick to the drill pattern that is provided in the build documents.  Good luck.


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## Jonathan (Aug 28, 2019)

SteveScott said:


> Your connections to your pots could be cleaner.  Definitely reflow your solder on the depth pot and trim excess wire.  But as chongmagic stated, you could stand to go over the whole thing and clean it up a bit.  You may find this helpful; I did.
> 
> 
> 
> And in the future, you may want to stick to pcb mounted pots.  It makes things much cleaner, and easier.  You just have to stick to the drill pattern that is provided in the build documents.  Good luck.


Thanks. Im off pcb mounted pots lately, I find the wired pots easier to fineagle in if I'm slightly off with my drilling (which I always am). Usually I just bend the wire and lay it flat against the pad and solder in place and don't have much trouble. I'm definitely not an expert but I've got a couple dozen builds done and I'm ok at troubleshooting usually. I'm confused as to why it modulates while turning but not when I stop. Maybe just a weak connection?


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## thedwest (Aug 28, 2019)

What’s going on with the resistor here? Im sure it’s legit but Im curious because I just don’t know enough about all of this stuff.


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## Jonathan (Aug 28, 2019)

thedwest said:


> What’s going on with the resistor here? Im sure it’s legit but Im curious because I just don’t know enough about all of this stuff.


I didn't have the exact value so I used 2 smaller resistors chained in series to add up to it. Resistors on series =r1+r2. You can also use them parallel but it divides the resistance. Opposite for capacitors, caps in series divides and caps in parallel adds.


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## thedwest (Aug 28, 2019)

Jonathan said:


> I didn't have the exact value so I used 2 smaller resistors chained in series to add up to it. Resistors on series =r1+r2. You can also use them parallel but it divides the resistance. Opposite for capacitors, caps in series divides and caps in parallel adds.


Cool. Thanks for the info and that's helpful to know! By the way, I used the fuzz on/off mod for the Chalumeau that you posted on here and it worked great. Definitely like having the ability to switch it off. Thanks for posting!


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## Jonathan (Aug 31, 2019)

OK I've gone over every point again with fresh solder, changed the pt2399 to a known working one, checked the voltage to the ics, and I actually removed some of the pots and soldered them directly to the components on the board based on the schematic and it's exactly the same. I get slight modulation when I turn the pots, then just slap back delay. I'm out of ideas.


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## zgrav (Aug 31, 2019)

I would check resistor values again, even though you've likely done that multiple times already.  Also verify that the electro caps on the depth control are oriented correctly.   Does the rate control work?  What about the others besides the depth control?  Are they doing anything?


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## Jonathan (Sep 1, 2019)

They all kind of do the same thing, there's a very slight effect while the knob is turning, then immediately stops when I stop turning the knob. It seems like they're affecting their appropriate characteristics but it's pretty subtle. Animate works, it oscillates if I turn it up all the way. I hadn't checked the resistors but I went thru with a multimeter and all are correct. Some of the readings were slightly off (1m resistor reading as 750k) but I assume that's because they're in the circuit and affected by other components. All the caps are oriented correctly and match values.


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