Zero Point Micro II no delay sounds

[morganp]

Hm, I wonder if it might be worth touching up those solder joints on the pots again, just to make sure they're making good contact... I'm also curious about the offboard wiring, that always seems to be the thing I mess up consistently.  Are the ins and outs going to a switch, or did you just hook up the jacks so far?

Of course, none of this has to do with the regulator being hot, which might be the first thing to solve.

[madbean]

I don't see anything obviously wrong with your build or the PCB itself. Have you tried remelting the solder joints on and around the PT2399? Possibly there could be a small solder bridge somewhere.

Also, I am curious to find this out: if after you remelt the joints and are still experiencing a problem, try pulling the PT2399 from its socket then take voltage measurements on pins 1 - 8.

[Aryk]

K I replaced it and now pin 4 has a 0.0v rating but the others remain the same. Which makes me believe it's not the IC anymore. I'll check the solder joints which have been reflowed already just to be sure. My guess is a wrong value cap or resistor any clues as to where I might look?


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[Aryk]

So with the PT2399 out voltages are ~9v at pin 1 and 0 everywhere else


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[madbean]

Are you sure? You should be getting 5v at pin1 regardless of whether or not the PT2399 is in or not.

[Aryk]

Sorry 5v


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[Aryk]

Where does the audio path run? Gonna go through with a probe and see where I'm not getting sound.


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[pogart]

Did you figure this out?. Oddly I am having the same issue. But regulator is not hot to touch. I did have feedback the first time I turned it on but we-worked a few solder points and that stopped but then no sound at all. Was thinking I fried something.

[Aryk]

Not yet don't know the audio path to test it out


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[pogart]

If I figure out my issue I will post it and maybe it will help out yours.

[Aryk]

Much obliged


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[morganp]

The build doc has a schematic; it takes some practice to read those, but if you print out the schematic and the board layout, you can follow the audio path with your audio probe on your board.  Start at the spot marked input on the schematic, try to find that on your board, and using your audio probe, work your way through the components that lead to the next stage, making sure the signal stays present.  You won't get sound on the side of a component that leads to ground, and you can also skip any connections that are leading to voltage. 

I just did this moments ago on my Azabache vero, I had a tiny bridge just before the output, ie, last thing in the path.

Oh, one thing to add, which you may already know, but on the schematic, the IC1 connections are shown as separate components, but they are just different pins off of the same IC.  The TL072 is a dual op-amp, so, yeah, two op-amps in the same package. 

[pogart]

Thank you morgan, I am firing up my DMM and will see if I can find a mix up, solder bridge or something. I have this feeling it is something obvious I am missing like a wire connected backwards.

[pogart]

Well it works now but I have to crank my amp to get volume from it.  It sounds amazing when I can hear it. A little "buzzy" and "crackly" when I am adjusting the pots but it is not fully enclosed in the box at the moment and wires are being wriggled as I adjust the effect levels so maybe that is the issue there. Any suggestions on the low volume when effect is engaged?. Jumps way up when I turn off the effect. Happy it works (sort of) and have to say it is one awesome sounding delay.

[morganp]

I get that sometimes if the signal is shorting to ground somewhere, or sometimes if you have the ground and lead reversed on your jacks.  You crank the amp up, and you can hear the effect a little, because some of that is bleeding through your ground. 

You might use your multimeter to check for continuity to ground where you should have none.  But I've found the audio probe to be even more useful for diagnosing.  If you follow that path on the schematic, and find the spot where the signal dies, you'll find the culprit. 

As a side note, I always feel like I learn much more when troubleshooting than when I'm just stuffing parts in a board.