Debug Aion Aurora compressor.

[Icescreamer]

Hi all,
This is my first post on this forum since so far I haven't had any problems with my diy effects that I couldn't fix after spending some time on it. The forum has been of a big help with previous projects, but my lack of electronics background is getting to me in this project.

I have build an aion electronics Ross style compressor, with atack knob and jangle box treble control. Details can be found here:
https://aionelectronics.com/project/aurora-ross-dyna-compressor/

This effect worked right away. However, after using it for a year it started having issues. While turned on, after sometime the sound would slowly choke until it was completely silent. I have had several attempts at repairing the effect. A couple of times I got it to work after reflowing solder joints. And some clean ups. It would work again, even though I never had the feeling that I really found the issue. The effect hasn't been working the last couple of months. I ordered new ca3080 also have the new produced ones from Rochester, swapped out a switch, but this hasn't solved my issues. I audio probed the effect and had audio signal until pin 2 and 3 from the ca3080. But no audio at pin 6.

I have the feeling that the signal goes to ground somewhere after the chip. The output signal is very free if noise.

Voltage readings are as follows:
Ic pin1: 0v
pin2: 4.92v
pin3: 4.92v
pin4: 0v
pin5: 0v
pin6: 2.92v
pin7: 9.43v
pin8: 0v

Readings from q1-q5 2n5088 pin 123 ebc
Q1: 2.05 2.44 7.38
Q2: 2.39 2.92 7
Q3: 0 0.59 0.07
Q4: 0 0 0.07
Q5: 0 0.07 9.43

Any help troubleshooting this is appreciated. My trial and error approach of addressing visually suspecious components hasn't got me any further on this one. And I really can't keep ordering new ca3080s from different sources.

Cheers

[PRR]

Welcome.

> I have had several attempts at repairing the effect. A couple of times I got it to work after reflowing solder joints. And some clean ups. It would work again, ... The effect hasn't been working the last couple of months.

While voltages suggest some issue around the Q3 Q4 Q5 clump, the history strongly suggests your solder joints are not absolutely reliable. There's like 130 joints here, so even "99% perfect" is not good enough. Inspect your boards and leads, check your solder, iron, and technique. Find *good* tutorials on good soldering.

[Icescreamer]

Thanks for your reply.

voltages suggest some issue around the Q3 Q4 Q5 clump, 

I ll take a look at the joints around this transistors.

This is the fifth pedal I build, and probably the easiest one, but I guess you re right, with 130 joints one bad joint is easily made.
However, I have a feeling some component has died since it sounded like the effect was slowly choking. As if some component was slowly getting fried. Is it likely that any of the tranies died, or some other component?

[Icescreamer]

Another note, for c11, which sits in between q 3,4 and 5, I used a tantalum cap. I thought I had read in the build documents that it was a recommendation, but I can't find it now. Is a tantalum a bad choice for this location?

[duck_arse]

also welcome. tantalum caps are usually fine when they are installed the right way round. most often they are marked for the "+" leg, whereas aluminium electros are marked for the "-" leg.

and - a bad or dry joint can die over time. if your component leg expands and contracts w/ the ambient temperature changes, even only microscopic distances, it will stress any less than best contact/connection until it fails. footswitches can also, in my experience, work/not work, if you overheat the lugs when soldering. that's really annoying.

[Icescreamer]

I confirmed that the tantalum caps orientation is correct. I checked the continuity between the all transistor legs and their neirest components. Everything seems goo. However, still no sound.

[Icescreamer]

Anyone who understands the network of transistors involving Q3, Q4 and Q5? Is there anything in the voltages pointing to any particular transistor?

[PRR]

> Q3, Q4 and Q5?

Readings 2n5088 pin 123 ebc
Q3: 0 0.59 0.07
Q4: 0 0 0.07
Q5: 0 0.07 9.43

With NO signal, base of Q3 should be ZERO.

There's not an obvious reason. It can even be big radio signals getting in (there's a ton of gain). Or it could be C10 leaking. Or bad solder-flux in the area. Or *maybe* a bad transistor, but that is the least likely unless you have been molesting them.

[Icescreamer]

Or it could be C10 leaking

Replaced c10...
You have solved the problem!

[duck_arse]

Or it could be C10 leaking

Replaced c10...
You have solved the problem!

just out of interest, what type/value of cap did you have at C10?

[Icescreamer]

Nice boxed metal film WIMA 10nF