What kind of wiring error gives you clean signal only? (A: a locked up PT2399)

[lincolnic]

So I'm building my roommate a Sea Urchin delay for his birthday (today). I put it on the test rig, everything worked. Now, after I've boxed it up, I'm only getting clean signal, even when the effect is engaged. Turning the effect on has no effect on the sound at all. My audio probe is only giving me clean signal too, no matter where I check.

I tested the 3PDT for proper continuity and it seems fine - continuity between the middle and bottom rows when the effect is off, and continuity between top and middle when it's on. I'm going to keep troubleshooting this right now, but in the meantime here's a picture. Hopefully someone will see the dumb thing I'm missing. Thanks!

(If anyone's wondering about the rubber band - I accidentally drilled the LED hole too high to put a nut on the bezel, so I'm gluing it in place.)

[lincolnic]

I desoldered the circuit from the switch and now I'm not getting any delay on the test rig either. Could this be the PT2399 locking up? I tried putting a quick jumper between pins 3 and 4 but it didn't do anything.

[jimilee]

That's exactly what it's doing. Did you remove the chip and put it back in after the jumper?

[Haberdasher]

yeah i can't see anything wrong with your wiring
btw you will probably want to solder a 100k across the 2 lugs of the output jack to eliminate any popping when engaged.

[jkokura]

Yeah, could be the PT2399. Or, you've had a short develop and the delay path is now going to ground somewhere.

Audio Probe?

Jacob

[lincolnic]

That's exactly what it's doing. Did you remove the chip and put it back in after the jumper?

Jimilee, you brilliant bastard. I don't know why, but removing the chip and putting it back solved the problem. Thanks all!

[jimilee]

That's exactly what it's doing. Did you remove the chip and put it back in after the jumper?

Jimilee, you brilliant bastard. I don't know why, but removing the chip and putting it back solved the problem. Thanks all!

Basically it unlocks it. Great news, i hope he likes it!

[madbean]

Another trick: if your PT2399 locks up, put it on the breadboard and ground all the pins. Presto, unlock. This has worked for me before.

[lincolnic]

Thanks Brian, that's a good one to file away. Also bonus shout-out to Keefe for reminding me about the output resistor.

Man, this is my fourth PT2399 build (Multiplex -> Neptune -> ZPSDX -> Urchin), but I've never had a chip lock up before. I'm not sure if it's better or worse when the thing you have to troubleshoot in your build isn't your fault!

This pedal also has shown me that I need to get an IC puller. Taking that PT2399 out without one was not fun.

[jkokura]

Another trick: if your PT2399 locks up, put it on the breadboard and ground all the pins. Presto, unlock. This has worked for me before.

Can you do this one pin at a time, or must all pins be grounded at the same time?

Jacob