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

Started by Miles, September 20, 2020, 07:28:29 PM

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Miles

Pro move - I should have known better, but I mixed up my Memory Man power supply (24 AC/AC I believe) and my Harbinger One (18v DC), and now, I have a problem with the Harbinger 'warbling' with squeal/hum at the rate of the speed knob. I replaced D1 but to no avail.

Any suggestions where I should be looking to diagnose this would be greatly appreciated.


Stomptown

I would start by checking the LM7815 voltage regulator.  According to the build doc for the Harbinger 1.5, you should have the following dc voltages:

In: 17.5v (square pad on PCB)
Gnd: 0v (middle pad on PCB)
Out: 14.74v (the other pad :))

Edit: if that checks out ok, I would check voltages of all transistors.

Miles

Appreciate the tip, but the transistors all check out. The bulb seems to be working just fine and the device does make the classic univibe sound. It's just the squeal/hum that's overlaid onto it. Any recommendations as to what I might want to look for next?

Stomptown

Hmm. The noise could be coming from the power section.  Are we dealing with the original Harbinger One or the 1.5 version?

Edit: assuming it's the Harbinger One, did you utilize the filter PCB?

jimilee

Is there a voltage protection diode? Don't have the BOM in front of me right now.


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Stomptown

Quote from: jimilee on September 21, 2020, 02:03:33 AM
Is there a voltage protection diode? Don't have the BOM in front of me right now.


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He replaced D1 which I'm assuming is the protection diode.

jimilee

Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

Miles

edit: The unit is the HarbingerOne_2015 model; the D6 diode is not present since I am running at 18v.

Stomptown

Quote from: Miles on September 21, 2020, 11:51:21 AM
edit: The unit is the HarbingerOne_2015 model; the D6 diode is not present since I am running at 18v.

Did you use the filter PCB to reduce noise for wall wart?

Scruffie

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.
Works at Lectric-FX

Miles

Stomptown: unless I'm mistaken - there was no filter portion for the Harbinger 2015 model.
Scruffie: I just wanted to clarify with you - it sounds like I have some work ahead of me, but I'll push through and get back to the thread. But - I wanted to state that I used the Total Recall power supply on it - which *was* AC (I think), so is it really a lost cause if that was the case??

Scruffie

The Total Recall supply isn't AC, don't worry.

You'd know if it was AC, it tends to make things... crispy.
Works at Lectric-FX

Miles

Scruffie - I've swapped C32, C33, and C34 but to no avail. Is it worth going down the line and replacing the rest of the capacitors if these check out ok?

Scruffie

Okay... the schematic I'm looking at only goes up to C32, you're going to have to link to what version you're using.

Are you using a regulator in it?
Works at Lectric-FX