Need A4000 Motherboard

[NightShade737]

Right, I have just got my A4000 motherboard back from repair to fix the mangled sound, and it is STILL completely screwed, so I need to get a new motherboard. Preferably one with Buster11 but I basically have no idea what I am looking for and I have virtually no money now as in total it has cost me £250 for basically a large ****ing paperweight, so I am short on paitence and temper as well as cash, that also being cash that I couldn't afford to spend in the first place.

So basically, if anyone has a spare board, or they think they can fix mine, can you please post.

[Morley]

The Germans are selling Amiga-hardware like h**l. Always something you need for sale there.

German ebay...

[downix]

Check pmail

[NightShade737]

Frankly I would rather not use eBay, this is how all of the problems start.

[doctorq]

Well, I would also stand in line for those who are willing to sell a A4k desktop motherboard at a fair price.

Actually I need two mobos, but one will do just fine. No zorro riser and/or cpu card is needed, but it would be nice to replace the 030 cards I have at the moment with a faster one.

[SilvrDrgn]

@ NightShade737,
What was wrong with the sound on your A4000 motherboard?

[NightShade737]

http://atomnet.co.uk/files/aaudio.mp3

[Morley]

Hey, that's not distortion, it's crap music :laughing:

[Castellen]

If whoever repaired it did not do a good job, send it back for a re-service.
As with anything, mistakes can happen and intermittent problems are common with electronics.

Explain the situation to them, and they should be happy to repair the audio problem at no additional cost to you.

The analogue audio stage in the A4000 is barely complicated, so it shouldn't be difficult to get it working properly.

[NightShade737]

I sent it off to have the 16v 22uF capasitors replaced, which he has done, but it had no effect. That was all the repair was for.

[Castellen]

It should have been tested before and after the job as you would with any other electronics repair.
Was it an Amiga specialist who did the job, or did you just ask someone in the know to replace the 22µF capacitors for you and not test it?

If the capacitors have leaked, there could be a problem with corroded PCB tracks which are causing bias imbalances on the op-amp.

Anyone with some basic knowledge of op-amps and analogue electronics should easily be able to repair it.

Schematics are readily available:
http://amiga.serveftp.net/

[NightShade737]

No, a standard TV repair bloke as all I was told I needed to do was replace the caps so I just found the easiest person to do it. There isn't anyone around here that knows how to repair Amigas, so that wasn't an option.

[Castellen]

Ahh, that explains it then.
Replacing the capacitors is only half the job.  Sometimes you can get away with doing that only, but if there has been damage caused by the capacitors or something else (like in your case) then you need to do a little more work.

Amiga.fr offer a good reliable service, or you can always send the board to me on the other side of the planet for repair :-P

[NightShade737]

No thanks, I'm sourcing out a new board instead. There was no obvious leaking on the board, so I assume the cap replacement would fix it, but nevermind.

[amigamad]

A4000 motherboard back from repair to fix the mangled sound, and it is STILL completely screwed

If thats the case send it back and tell them you want it fixed seeing as thats what they were paid to do. :-?