Harbinger One - I nuked it w/ AC 24v. Now it warbles/squeals at speed value.

[Scruffie]

Ohhh, I was looking at the wrong one... So it does have a series protection diode.

Well, my advice either way is the same, try replacing the regulator.

[Miles]

I previously had checked the LM7815 and the values I was reading were consistent with the documentation and advice provided in this thread. I want to make sure it's still a good idea to swap it out or if there was something else I should be looking for.

[jimilee]

I previously had checked the LM7815 and the values I was reading were consistent with the documentation and advice provided in this thread. I want to make sure it's still a good idea to swap it out or if there was something else I should be looking for.

You can't break it at this point, I don't see why not.


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[Miles]

Part is ordered and we'll find out Thursday. Thanks.

[Miles]

Part was replaced, no discernible change, sadly.

[Scruffie]

Darn, at least you know the power supply is all clean now.

Next step will be to audio probe through the circuit to try and pin point what took a hit.

[midwayfair]

It's very likely just one of the electro's in the power section, the parallel protection diodes aren't as fool proof as series. You nuked it with DC (if it was AC, I'd tell you to bin it and start over) but of the wrong polarity (also those supplies are unloaded so can be higher voltage than stated) so whatever the electro next in line to the protection diode, replace it and then the next etc.

^ It's this almost for certain, there is an electrolytic SOMEWHERE in a power rail that was blown. What you've described is textbook power rail squeal.

It could be any of C19-C22 or C30-C32, and if it was, then the squeal should be everywhere in the circuit (though it might be louder as you go through).

[Miles]

In fact, there is squeal everywhere in the circuit. I started by replacing C1 assuming that's where the squeal began, and then was confronted with the same squeal. I am actively looking into this. Thanks for the heads up.

[Miles]

One thing I noticed is that there are no electrolytic capacitors (or any for that matter) from C19-C21. Only C22. Just confirming the others mentioned apply to the 2015 model. I have them on order now.

[midwayfair]

One thing I noticed is that there are no electrolytic capacitors (or any for that matter) from C19-C21. Only C22. Just confirming the others mentioned apply to the 2015 model. I have them on order now.

Post a link to the schematic you're building from. There's at least two PDFs of the harbinger.

[Scruffie]

One thing I noticed is that there are no electrolytic capacitors (or any for that matter) from C19-C21. Only C22. Just confirming the others mentioned apply to the 2015 model. I have them on order now.

Post a link to the schematic you're building from. There's at least two PDFs of the harbinger.

He did 

It's in the 2015 subfolder in the zip archive:

https://www.madbeanpedals.com/projects/archives/FilterMod/HarbingerOne.zip

[Miles]

Everything squeals starting from the first component. I really don't want to chuck this in the bin, but am I out of options here?

[Stomptown]

Have you tried another power supply?

[Miles]

Yes, I've tried a variety including a MXR ISO-Block.

[jimilee]

 

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