Here's more data for those who want to replace capacitors on both A1200 and A600 machines:
http://eab.abime.net/showthread.php?t=44138

hm yeah a quick answerer I was, sorry Your machine is indeed PAL!

Garbled text could be anything like corrupted memory. This can happen after you run some shit, some program crashes and what not. Always make your tests after a cold boot.

Regarding the speed, it could be anything, probably teh demo is pushing the machine too hard. Are you sure you are running a demo apt for a STOCK A1200?

It's a PAL machine! And I wasn't switching it to NTSC at boot.

Ok, I'll try switching out the audio capacitors then and see if that helps. I will have to order more to do the rest though.

There are no such things as loose connections inside an Amiga or something that feeble that would cause random bugs, this is a modern computer, not a C64
I think your problem is trying to run demos on an NTSC machine. Did you switch it to PAL? Nothing runs in NTSC, basically.

Capacitor problem. Change them immediately before they make any more problems.
You can't be sure of any further troubles unless you change EVERY capacitor in the Amiga, not just audio. Capacitors are top on the list when troubleshooting Amiga SMD hardware.

Yeah I think it's a PC PSU.

Well, I made an audio probe, but now the video on my Amiga is malfunctioning as well. It boots to Workbench just fine, but when I ran some demos the text was garbled and one alternated between running too fast and too slow. It was working fine a minute before! Maybe I accidentally fried something with static when I was moving it around? Or hopefully it's just a loose connection somewhere?

EDIT: And now my audio has started working, albeit at an extremely low volume!

EDIT2: Audio is garbled sometimes though. I am also getting freezes and crashes.

Is "sketchy": actually a PC PSU? If so, that'd be much better than an Amiga one.
I don't think this would cause MISSING AUDIO at all. You should replace the caps nonetheless.

Thanks for the links! I have ordered non-SMD replacements though, so only the desoldering should be tricky.

Interesting! The PSU I'm using is actually some very sketchy DIY thing the previous owner of my Amiga made. It may very well be the problem! I'll look into this, and if it is the problem, then I guess I'll just have the replacement caps ready for the future when they really do fail.

Re: SMD soldering. It's pretty easy if you get the technique down. Check out this pdf as an example from sparkfun http://www.sparkfun.com/datasheets/Prot … Basics.pdf ... also this page has a lot more if you scroll down: http://www.sparkfun.com/commerce/tutori … als_id=107

You may want to check your power supply or the audio circuit with a multimeter. It's possible that your supply "works" but fucks up the audio. This was an issue with my first amiga and didn't really think of it until you said the caps were clean. There's a simple way to test for this/should be some instructions on aminet.

I just ordered replacement caps for my Amiga and TV, and also parts to make a simple audio probe.

Thanks for the links man. I'm gonna order some parts.

Hi man.
This link might help:
http://eab.abime.net/showthread.php?t=55430

This guy swapped out the audio caps. you can look at the position where they are (near the audio ports). He also mentions something about non-polarized caps.

Hope it helps.

Amigakit? Bah, man, armed robbery.
As I said, ANY electronic technician CAN do this. You just have to tell him exactly what to do (change the caps). Also, as I said, it is recommended that ALL capacitors on the mothrboard are changed, since they are a source of problems, so you can just take it to this technician and ask him to replace for equivalent, NON SMT components, paying attention to make double-sure the ratings are the same.

I will, again, strongly recommend AGAINST doing this on your own, but it's your Amiga after all. Just think you might pass from having a defective computer to having a very expensive and funky looking doorstep.

You tried many other softwares with audio? Did they have audio? If no, the caps are probably the problem. Now, if you have other problems too (serial I/O, floppy access, mouse) then Paula might be defective. But this is a VERY unlikely scenario.

This link might help:
http://joj.home.texas.net/amigacap.html

Here they describe the prob on an A4000, which is almost the same (A600s, A1200s and A4000s suffer the same problem with defective surface mount caps):
http://www.amiga.org/forums/showthread.php?t=41357

I took my Amiga apart to look at the motherboard, and I'm not afraid to try SMD soldering. I'll just need some tweezers and a steady hand.

However, nothing looks corroded and all the solder joints are shiny. Is there a way to pinpoint the problem? I want to make sure that the caps are actually the problem before I start the surgery.

Ah. I've never tried soldering SMD before. There's always a first time right? I'll open up the Amiga to look at it first and decided if I think it's something I can do or not. Coincidentally, I also need to replace the caps in my TV.

EDIT: Amigakit do a cap replacement service, but including shipping it would cost nearly as much as I paid for the Amiga in the first place.
It actually costs the same amount to just buy another motherboard from them. So I might as well try and fix mine myself, and if I mess it up, buy another one.