A1200 sound question

Whats the most likely reason going to be for losing sound on a 1200 ?

Currently all I get is static, have checked the wires and speakers I'm using to make sure that there isn't a problem there.

Thanks

most common thing for sound problems now-a-days is the caps, i know it's a boring reply, but it is the most common:(

Its what I sort of figured, just wanted to check before I try and sort out getting them replaced.

Thanks

Try a known perfect PSU first, or test your current PSU on another miggy before you risk damaging the board or paying out for a new one / repair.
The motherboard isnt the only place that has caps that can reduce the quality of the current to the miggy's sound circuits. I once went through a few perfectly good boards before discovering it was the PSU at fault, which wasted a lot of money and a couple of perfectly fine boards. :huh:

Adding my voice to the "check the PSU!" chorus. Once had mysterious failures on my A500, noticed I was using the C128 power supply by mistake! Oops! (Lucky nothing blew but could have! The 128 supply gives 9VAC where the Amiga expects 12V DC!)

So, check your 12V line. Quicker check: does your floppy drive work? It needs 12V, too.

I'll do that, but will be just as annoyed if my goliath psu has decided to stop working :-)

Got an A500 one somewhere.

A problematic PSU will not stop the sound output! A faulty +12V or -12V (not both at the same time!) will make the audio faint and heavily distorted.

No audio at all can be caused by the two decoupling capacitors on the audio output (C324 and C334, the same parts for A600 and A1200), but this is even unlikely. But since the replacement is not hard to do... DO IT FIRST!

After that, if still no sound, the probable culprit is the op-amp of the audio section. In both A600 & A1200 the part is a SMD LF347 chip.

On the A1200 it is located under the HD cage, a few centimetres from the keyboard connector.

Replacement of this chip is a bit difficult and must be conducted by someone who knows how to solder SMD parts.

Unfortunately it looks like my Goliath psu is at fault as I found the A500 psu and sound works fine.

Guess its time to invest in a new one.

http://www.ianstedman.co.uk/Amiga/am..._supplies.html

Thanks for the info.