SOLVED Having the weirdest problem yet...

[mboyd43]

Had an old double tracker build that worked great, but I wanted to repaint the enclosure. Now when engaged the dry signal comes through but the modulated path is pure static. Here's where it gets weird: it works when I unscrew the jacks and plug it in loose through the back. Only with both out. One or the other screwed in and static, so I don't believe it's one problem on one side. Tried attaching a nylon but so the jacks don't ground to the enclosure, no luck. Tried changing jacks, same thing. So confused

Edit: the static is triggered when the jack's ground make contact with the enclosure. With them out, there's continuity from Jack ground to DC ground, and no continuity from enclosure to DC ground.

 

[Nostradoomus]

You want the jacks touching the enclosure at the top. Make sure the jack tabs aren't making contact with the enclosure or the power supply pins (the output jack looks real close to both at that angle) Try using a multimeter to check for ground continuity/piossible shorts on all the jack tabs when it's tightened up like it should be.

(edit: does the dry signal still work regardless of all that?)

 

[DailyDovetails]

I agree with @Nostradoomus . I think it’s right here.


Sometimes if it’s a tight fit I will turn that jack 180 to make the input closer to the center. I think jacks like this are easier as they are not exposed on the sides. https://www.taydaelectronics.com/45015-dup-6-35mm-1-4-stereo-phone-jack.html

 

[mboyd43]

You want the jacks touching the enclosure at the top. Make sure the jack tabs aren't making contact with the enclosure or the power supply pins (the output jack looks real close to both at that angle) Try using a multimeter to check for ground continuity/piossible shorts on all the jack tabs when it's tightened up like it should be.

(edit: does the dry signal still work regardless of all that?)

You would think so, so not sure why them making contact triggers the static. They are close to the DC pins but no contact. Dry signal does work in all situations.

With the jacks out, a few parts that lead to ground on the schem have continuity to the enclosure. DC ground to enclosure, no continuity. Hm

 

[mboyd43]

I agree with @Nostradoomus . I think it’s right here.
View attachment 88045

Sometimes if it’s a tight fit I will turn that jack 180 to make the input closer to the center. I think jacks like this are easier as they are not exposed on the sides. https://www.taydaelectronics.com/45015-dup-6-35mm-1-4-stereo-phone-jack.html

Good catch, but I have rotated it and still same thing.

 

[DailyDovetails]

I’m not 100% sure but I think you leave the LED unpopulated if you’re not using it. I think the way it is now might be dumping + to ground. Is it when it touches the enclosure at all?

 

[mboyd43]

I’m not 100% sure but I think you leave the LED unpopulated if you’re not using it. I think the way it is now might be dumping + to ground. Is it when it touches the enclosure at all?

Yeah, you tap the jack sleeve to the enclosure and it's like a big reverby pop static noise. I think something being dumped to ground is on the right track. Not sure what you mean about the LED though, there's 1 LED Spot that I'm seeing

 

[DailyDovetails]

I thought that looked like a jumper. Is it an LED?

 

[mboyd43]

View attachment 88047
I thought that looked like a jumper. Is it an LED?

LED, the white arc is the graphic on the PCB

 

[Robert]

Make sure the pots aren't touching the back of the PCB.

Loosening the jacks is removing the ground connection to the enclosure, it sounds like something is coming in contact with the enclosure that shouldn't.

 

[mboyd43]

Solved! Once I started looking for stuff making contact with the enclosure I took it out and saw the resistor on the potand knew that had to be it. Pressed it down and taped it up, and we're good. Thanks for your help guys