SOLVED Need a second set of eyes (Duo-Phase)

[DGWVI]

Hopefully the pics are clear enough

Having an issue with the power delivery on the B side of this latest Duo-Phase- the LFO will not start, but the phase stages work otherwise.


I've gone over everything several times, and have replaced everything in the LFO section and power sections for Side B and kinda stuck on what to do next. The Depth and Trimpots all effect the LEDs as they're expected to, but I get no movement from the LFO

Removed the Feedback pot to make photos easier.



Voltages for the borked side... As you can see I'm getting static negative voltages on both ICs 5B and 6B, even after resoldering, cleaning, replacing (everything, including the switches but, except the sockets), and cleaning again

I also get continuity between IC6B and all three pins of the LFO switchz regardless of which position it's in.


Voltages for the working side


I've gone over everything with a flashlight and magnifier, and see no solder bridges or damaged traces.
Side A works perfectly

 

[jhaneyzz]

Not ignoring ya, just not much to add.

I also get continuity between IC6B and all three pins of the LFO switchz regardless of which position it's in.

It's gotta be around there.... replace the socket? I've had that help a total of one time, but it's a thing.

 

[DGWVI]

Not ignoring ya, just not much to add.



It's gotta be around there.... replace the socket? I've had that help a total of one time, but it's a thing.

Yeah, that's the next step. And sockets are the only thing I suck at desoldering

 

[jhaneyzz]

Just hold the iron on until you smell burning plastic... thats what works for me...

 

[jhaneyzz]

 

[swyse]

Yeah, that's the next step. And sockets are the only thing I suck at desoldering

I read somewhere to clip off the plastic and make it desoldering one pad 8 times instead of 8 pads one time if you can.

 

[DGWVI]

I read somewhere to clip off the plastic and make it desoldering one pad 8 times instead of 8 pads one time if you can.

It's more the issue that the pins are super snug in the holes, so getting enough solder out with a pump isn't the easiest thing.

I have verified there are no bridges between any of the pins or adjacent components, though

 

[Nostradoomus]

Is R34B 120r? Can’t really see it, looks like it might be 1k

 

[delayed]

Have you double checked your tants for polarity? Sometimes the + side marking can lead to installing backwards.

 

[delayed]

R34. Good catch. Looks like you might be correct.

 

[DGWVI]

Is R34B 120r? Can’t really see it, looks like it might be 1k

R34. Good catch. Looks like you might be correct.

These are heavily modified, so I left the values out. The LFOs in particular have been adjusted to have as wide a range as possible, but I felt that that was largely irrelevant to this issue as the last Phase II I built, and Side A of this particular board work perfectly and have the same values used here. I've also swapped out all of the components in both the LFO and power sections for this side of the board.


The phase stages all work properly, and the pots that control LEDs work fine. There's just something fucky with the power that I've not been able to spot

Have you double checked your tants for polarity? Sometimes the + side marking can lead to installing backwards.

So many times
I'll pop those out tomorrow when I get back to it, and swap them for new ones

 

[Betty Wont]

One more longshot… the component layout of this pcb is not completely symmetrical. There are a pair of resistors that are in different spots on their respective sides. I’ve seen a couple of troubleshooting threads caused by the assumption that it’s a mirror build.

 

[DGWVI]

One more longshot… the component layout of this pcb is not completely symmetrical. There are a pair of resistors that are in different spots on their respective sides. I’ve seen a couple of troubleshooting threads caused by the assumption that it’s a mirror build.

Yep! One of the first things I looked at, actually. But they're correct

 

[Betty Wont]

Yep! One of the first things I looked at, actually. But they're correct
View attachment 44929

Very good. I mean this in the most respectful way, truly, and I love to be a contrarian… but I disagree with every single component type choice on this entire build. It’s like the Rueben sandwich. They put every food I can’t stand (down to the bread) together in one place. I can’t comprehend this madness …please be my friend.

 

[jhaneyzz]

at least he didn't use green LEDs for the opto...

 

[Guardians of the analog]

Very good. I mean this in the most respectful way, truly, and I love to be a contrarian… but I disagree with every single component type choice on this entire build. It’s like the Rueben sandwich. They put every food I can’t stand (down to the bread) together in one place. I can’t comprehend this madness …please be my friend.

 

[Harry Klippton]

Very good. I mean this in the most respectful way, truly, and I love to be a contrarian… but I disagree with every single component type choice on this entire build. It’s like the Rueben sandwich. They put every food I can’t stand (down to the bread) together in one place. I can’t comprehend this madness …please be my friend.

I can't live without my medicinal fermented cabbage. I'll take it in whatever form

 

[DGWVI]

I can't live without my medicinal fermented cabbage. I'll take it in whatever form

I'm a cabbage goblin- I'll eat kimchi and sauerkraut straight from the jar
Or even raw right off the head
Or in a variety of slaws
Or a veggie burrito with cabbage replacing the lettuce

 

[jhaneyzz]

I'm a cabbage goblin- I'll eat kimchi and sauerkraut straight from the jar
Or even raw right off the head
Or in a variety of slaws
Or a veggie burrito with cabbage replacing the lettuce

How do you unsubscribe a message thread...

 

[DGWVI]

How do you unsubscribe a message thread...