genesis crackle

[blackevilweredragon]

My Genesis model 1 has started crackling on the right speaker...

It does this through the headphone jack..  I even replaced the jack and soldered on a new one, and it still crackles through the right speaker..  headphones, TV, whatever I use, there's crackling..

What can be causing this?

EDIT:  Noticed something..  It only does it when the 32X is plugged into the cartridge port..  When the Genesis is booting up, at the license screen is on, it's nice and silent, as soon as the 32X powers on and you hear that "pop", the crackle starts..

So, it's the 32X causing it..  (even if I pipe a Genesis game through the 32X, it's fine...)

[blackevilweredragon]

UPDATE:  I have tried cleaning the contacts, but no luck..  Btw, how DOES the audio get into the Genesis?  The cartridge pinout does not mention an audio line...

[NFG]

Audio doesn't go into the genny, it comes out of the genny.  There's an audio input on the expansion connector but it's mono (at least on the original, I think it's stereo on the Gen2).

[blackevilweredragon]

Audio doesn't go into the genny, it comes out of the genny.  There's an audio input on the expansion connector but it's mono (at least on the original, I think it's stereo on the Gen2).

Just curious though, how does the 32X mix it's extended PWM (or is it PCM), with the Genesis then?  If I unplug the A/V cable going from the Genesis to the 32X, there is absolutely no audio then, so it's getting mixed in the Genesis somehow, it just has to be..

When playing Knuckles Chaotix, I do know the drums and percussions are coming from the 32X, as it says right in the sound test, it's not the DAC, it's PWM (and from what I read online, the PWM is in the 32x, which provide 10-bit audio)..

And the thing is, if it doesn't go INTO the Genesis, how is it, that when plugging headphones into my model 1 Genesis, I can easily hear the PWM audio from the 32x?  It makes no sense at all to me...

(also, worth mentioning, is when it's crackling, as soon as I pull the 32X out of the Genesis while it's running, though the music continues to play, as it's in the Z80's RAM, the drums go away, as it's PWM, but so does the crackling..)

I also know it's not the Genesis that's failing, all Genesis games passed through the 32X work fine, it's only when the 32X is actually "on", does it crackle...

[NFG]

As far as I knew all mixing took place in the 32X, I'm quite surprised to hear you get 32X audio out of the headphone port.

As for crackling, it isn't necessarily a bad connection in the cart port, it could just as easily be bad power, a blown audio amp or mixer, or a bad connection inside the 32X.  

I'd replace the 32X and/or Genny and see what happens.  That'll help narrow down the possibilities, and both parts are cheap.

[blackevilweredragon]

As far as I knew all mixing took place in the 32X, I'm quite surprised to hear you get 32X audio out of the headphone port.

As for crackling, it isn't necessarily a bad connection in the cart port, it could just as easily be bad power, a blown audio amp or mixer, or a bad connection inside the 32X.  

I'd replace the 32X and/or Genny and see what happens.  That'll help narrow down the possibilities, and both parts are cheap.

Yea, I could hear all 32X sounds out of the headphone port...  Only oddity that way, the left and right are reversed...

I tried my Genesis 2, has crackle with 32X also, tried a friends 32X, NO crackle on both Genesis...

So it's my 32X..

Just for a trial, I'm gonna open up my Genesis, tilt it on it's side, and while the 32X is running a Sound Test, I'm gonna test each individual pin, just to see if there is an chance that maybe a pin or two dubs as audio, along with data (maybe it uses some kind of filter?)..

[blackevilweredragon]

Lawrence, you're gonna hate me when I say this, but I was right...

I found both stereo left and right pins for audio on the cartridge port, don't know which is which (how would I even test that!)

The pins are B1 and B3...  

Here's an audio clip of B3   http://blackevilweredragon.spymac.com/GenB3.mp3[/URL]

[NFG]

Lawrence, you're gonna hate me when I say this, but I was right...

Hah.  I love to be proven wrong, everything we add to a discussion makes us all a little smarter next time.  =)

Good work.

[blackevilweredragon]

Lawrence, you're gonna hate me when I say this, but I was right...

Hah.  I love to be proven wrong, everything we add to a discussion makes us all a little smarter next time.  =)

Good work.

heh, thanks..  my work there was definitely trial and error, some points resetted the genesis, while others made the headphones make a loud POP sound..

but B1 and B3, I heard drums, and I knew immediately, "holy crap!  I was right!!"  LOL

I guess that clears up two pins on this chart of yours:  http://www.gamesx.com/cartouts/gennycart.htm

[Endymion]

As far as I knew all mixing took place in the 32X, I'm quite surprised to hear you get 32X audio out of the headphone port.

The mixing definitely went through to the Genesis, as bewd saw. Those of us hardcore who had the original model 1 and the first SegaCD unit had all of the audio, including the 32x, from the SegaCD's stereo outputs.

[blackevilweredragon]

Also Lawrence, if you want, I can test the audio pins on both Genesis models (as your expansion port pinout says it's untested)...

To see if it's full stereo, or mono in the old one, and the model II genesis..  I have a flat edge connector I can use to pump music through the pins via my iPod, and see if I can hear it in full stereo on my TV..

Also, I used my fathers air compressor, and cleaned out my 32X, along with reseating those famous ribbons, and the crackling is gone now on my 32x...

[Ismail Saeed]

Now that is very cool, that your problem got fixed.  I hope the other ones you've posted about get fixed.  I learned a bit more about another console today .

Hopefully I have the same luck as you in due time...