A1200 sound problem .. Pls help

[dougal]

Hi guys ,

My A1200 has a wierd problem with the sound output .

The sound comes out from the L & R phono sockets , but with both L & R plugged it comes out with missing channels .

If i unplug one of the (forgot which one) the sound works fine with all channels present but obviously i don`t think stereo is working ..    

I seem to remember that supposedly if you unplug a phono from the back you lose half the sound ..

Strange .. Any ideas ? Is my Amiga slightly screwed ?

Here is the spec : A1200 K/S 3.0 with Blizzard 030 50Mhz accelerator & 16mb fast ram . 520Mb 2.5" IDE drive , & Scsi 4x CDROM through PCMCIA .. Powered by A600 standard PSU .

[Matt_H]

Not sure what the problem is, but all sound will be routed to one audio port if it's the only one plugged in (intended for people who only own mono monitors). Also don't know if that's an Amiga feature, or a general truth about electronics.

Maybe there's some gunk in one of the audio sockets?

[Amiduffer]

I remember a problem like that. I had the polarities reversed and the sound came out almost incomprehensible. Check to make sure that the left RCA connector is connected to the correct socket on your stereo/amplifier, and that the Right is also, etc. if that is how you are playing the sound.

Amiduffer

[dougal]

check it .. it is a loose phono plug on the cable ..

Thanks

[Castellen]

The Amiga RCA jacks have built in switches so that if only one RCA cable is plugged in (for mono systems) then the other audio channel is connected so that both of the output channels are joined together at the single RCA output.

If two RCA plugs are connected, the left and right outputs are seperated.

Your problem sounds like one of the audio output stages is dead.  Quite likely to be the 22µF electrolytic capacitors leaking corrosive electrolyte onto the board.

I've written a complete guide on this as well as an audio test utility to help testing and repair:
http://amiga.serveftp.net/audio_repair.html

Unfortunately my webserver is offline right now due to my ISP being a giant arse, but should hepefully be back in a day or two.
Perhaps Google or WayBackMachine might have cached the page so you might be able to see it in the meantime.