Hum and no audio

[Paul Birkeland]

Perfect, now grab your Reduction and plug those RCA cables into the inputs.  You don't need to apply power to the Reduction, just the RCA cables.

Now read the AC voltage across the input jacks.

[ryburdman]

2.5 red
2.3 black

[Paul Birkeland]

OK, that tells you that the input jacks aren't clogged with debris.

Power the Reduction up and play that tone into the inputs.  You can just anchor your black meter probe to the grounding screw if that's easy for you, then measure the AC voltage at:

6
10
19
23

[ryburdman]

6-0
10-2.5
19-0
23-10

[Paul Birkeland]

6-0
10-2.5

6 really can't be 0V if 10 is 2.5.  You're also missing units, is that 2.5V or 2.5mV? 

19-0
23-10

Ditto here, 10V? 10mV? What AC voltage do you see at terminal 27?

[ryburdman]

Sorry, i was all mess up on the last one heres a retry
6-13mv takes a bit to get there starts at like 6 and slowly climbs
10-230mv
19-0 and one of the led's blinks when i test it
23-140mv
27 -12mv takes a bit to get there starts at like 6 and slowly climbs

[Paul Birkeland]

19-0 and one of the led's blinks when i test it

You have a loose connection, that causes the LED to blink.

[ryburdman]

After probing more, it only makes a led blink off if I have the Fluke in mv if its in regular ac volts I don't get the Lightning bolt icon and the led doesn't go off, I am wondering if that's the meter causing the leds to go out.

[Paul Birkeland]

No, you have a loose connection making the LED flash.  There isn't anything about what the meter is up to that will cause that. 

[ryburdman]

Ok if that's the case, when I measure with the meter in ac mv heres where leds blink
2- led to 3
7- both leds
13-led to 3
14 led to 3
15 both

---------
18 both
19 led to 9
20 led to 9
26 both
29 9
31 9

Sorry this is taking so much of you time and such a pain, I really appreciate the help.

[Paul Birkeland]

6-13mv takes a bit to get there starts at like 6 and slowly climbs
27 -12mv takes a bit to get there starts at like 6 and slowly climbs

Ignore what I said previously about 19.  What we see with 6 and 27 is the amplification after the first stage.  You have 13mV and 12mV of signal coming out.  This is way lower than what I would expect with 2.5mV of signal coming in, but it's consistent.

Can you carefully measure the AC voltage again at 10 and 23?  If you have 12-13mV at 6 and 27, you can expect far more than that at 10 and 23. 

[ryburdman]

10-230 mv
23- 140mv

I just want to mention as to make sure i am doing this correctly. When I am just holding the red probe in the air with the black connected i am reading around 260mv, if I unclip the ground and just hold both in the air I am reading 60mv. The readings I am giving you are when black is clipped to the ground and red its touching 10 or 23.

[Paul Birkeland]

Yes, the black probe needs to go to the ground lug on the chassis and the red probes to the terminals in question.

The reading on 23 indicates that your Reduction is passing some signal, but not a sufficient amount.

Can you post some fresh photos like the first set you posted?  In that set of images, I saw lots of issues and perhaps some of those are still present. 

If all else fails we can get you setup with a flat rate repair, but I would not at all be surprised to find that if I reflow all your solder joints, your Reduction will work fine. 

[ryburdman]

Here is a new set

https://photos.app.goo.gl/v5dcuCkjJgmHqJyB8

[Paul Birkeland]

The 0.47uF cap on the left channel looks like the leads are snapped coming out of one end.