Nearly silent audio in my SE/30

[drmadison]

I've been enjoying my SE/30 for a bit now, but the audio is lacking. I can get quiet audio from my headphones if I set volumes to max. If I try to run it through powered speakers I have to crank it to the point where the signal gets rather noisy and unpleasant. Needless to say the built-in speaker doesn't make a peep.

I'm curious if other people have run into this. The machine looks like it was recapped not too long ago, but I wasn't the one that did it so that doesn't mean I'm sure it was PROPERLY recapped (and even if I did it myself... that means nothing haha). I suspected maybe an incorrect cap or something was put in, or possibly busted opamp, but figured I'd see if others have seen this before I start multimetering the whole damned board in hopes of finding something out of sheer luck... Like I said audio is present on the headphone jack (though quiet even at max volume) so at some point the circuitry is functioning, at least partially. Or maybe this is just how the SE/30 is and it never had very loud audio? Not having used another before it's hard to say...

 

[bibilit]

IIRC, the cap responsible for the audio is the only 1 µf 50 v present in the LB, probabaly worth checking.

 

[ymk]

Several 47uF caps are in the audio path as well.

 

[joshc]

Sometimes that area isn't cleaned up properly. Got any photos of your board?

Sound circuit diagram here:

https://recapamac.com.au/wp-content/uploads/2020/05/se30_sound_chips.jpg

Or maybe this is just how the SE/30 is and it never had very loud audio?

No, the audio should get quite loud.

 

[drmadison]

Awesome this is all super helpful.
Attached are some shots of the mainboard front and back (with maxed ram, but stock rom-simm as I was playing w/ A/UX on it which didn't like the 32-bit clean rom...). Started looking through that circuit diagram and so far all of the connections that should be there are but a lot more to check still!

 

[Bolle]

That board wasn't recapped. Still has all factory caps in place and you can already see signs of corrosion/dull solder joints around all caps.
Boards needs a proper cleaning and recap.

 

[drmadison]

That board wasn't recapped. Still has all factory caps in place and you can already see signs of corrosion/dull solder joints around all caps.
Boards needs a proper cleaning and recap.

Then I have been lied to!
I believed it due to some of the caps being notably smaller than the outlines on the board which I know is sometimes the case when using newer components. Guess that tells me what my next step is.

 

[joshc]

Yeah, definitely not recapped I'm afraid - you can tell by all the dirt and fluff around the caps too, and like Bolle said the dull solder joints.

 

[drmadison]

All part of the learning process I guess. At least this gives me a solid guess as to what the issue probably is.
Also, oddly enough, things look a lot dirtier in that photo than they do just looking here at the board in person...

Thanks again all!

 

[nottomhanks]

I picked up a used SE that was upgraded to an SE/30 and my sound was super quiet as well. It’s being recapped this month.

 

[drmadison]

This morning was the first time I heard my SE/30's boot up chime!
It was a bit of a painful recap, as the tantalum caps I got were larger than the original electrolytics so getting enough pad space to solder took time.
Also along the way I learned that if I'm going to attempt this again, I need some tool upgrades.
My magnifying glass just doesn't reach far enough away, ended up being in the way as much as it was useful.
And if I'm desoldering these tiny SMD components again, I really need hot air... doing it with a soldering iron was a pain.

Lost 2 pads in the process, 1 was easy as it went to a nearby pin so easy bodge. The other of course went to a surface mount resistor on the other side of the board so I had to get a bit creative.

All's not entirely perfect, as I'm getting some slight popping in the audio (not noticeable in alert sounds, but if I play a longer sound or for instance the intro music to dark castle it pops a bit), and the system is locking up when shutting it down which it didn't do previously, so I need to go back over the board again but for now, I'm going to take the win.