help my amiga 4000 has little or no sound output

[Darmaster70]

One question for you silver dragon, when your computer boots do you get the dark grey light grey white boot colors?

Well, my computer has the same problem as Silver Dragons, and I don't get any different boot colors.

[SilvrDrgn]

I get no colors at all during bootup.

   Well i had the same problem on the output sound on my A4000...so i decided to look on the Mainboard and discovered that Batterys aren´t the only things that leaks acid on the boards...Capacitors can do the same damadge...look the capacitors ( C433 22uF 16v ) there are two, between Paula and the RCA jackets...for my Amiga was too late i hope my experience can save others Amigas...well...my A4000 is not dead...it works, but...no Sound   :-(

P.S.
PC´s are good machines, only if tey´re runnin Linux :-D

[Darmaster70]

Thanks for the information, My wife made me put the 4000 in the closet. She hates it when my desk gets messy. Her desk is pristine. I've got my 2000 hooked up right now as well as my Dell pc. I use the Dell for internet and work purposes and I hate windows with a passion. I think I'll pull out the 4000 this weekend and have a look.  

[SilvrDrgn]

@ zeewolf,
I will have a look at my A4000 motherboard when I get a chance.  Thank you for the information.

   there is on the net an Hardware hack explaining how to repair this problem...but i have no knowlege on electronics...so the simple solution is to remove those capacitors "i´ve done that" and buy a 2nd hand sound card...somewone tryed to sell me one, a tocatta sound card for...350 €   !!!???

[SilvrDrgn]

@ zeewolf,

there is on the net an Hardware hack explaining how to repair this problem

I've been looking for it, but cannot find it.  Where is it please - URL

(I'd love a sound card, but am saving cash for an AmigaOne system.)

ok, here it is.

http://joj.home.texas.net/amigacap.html

So if this is what is killing the sound on my 4000, I should be able to see leakage?  I don't see anything leaking, but am wondering if it could still be the same problem and if I need to do the capacitor fix anyway.

Hmm, oh well.  Guess I'll throw the 4000's in the dumpster then.

Okay, let's take this in another direction.  (Well first, did this fix help the other flaky sounding 4000's out there?)  If I get a sound card (Where can I get one of the Melody cards that uses the 1200 clock port?), is there a way to make all sound go through that instead of using the system sound?

[SilvrDrgn]

Over the Christmas holiday, I took my A4000T to my dealer in St. Paul, Minnesota (Raymond Computer).  We hooked everything up so I could let him hear the problem.  Unfortunately, he was pretty busy that day, so the only thing we were able to do for testing stuff on the motherboard was use his Advanced Amiga Analyzer package.  Plugged in the port dongles which have LEDs on them for checking certain pins.  Powered up and discovered that the +12 volt supply is not present on any of the ports that it's supposed to be.  That supply, along with the -12 supply, also powers the op-amp chips that produce sound from the motherboard.  Obviously, without it being there will produce the lack of or very low sound output.  Thankfully, that +12 supply for the ports and the sound is on an isolated circuit.  So, he thinks likely a fuse is blown or a trace is burnt out somehow.  We'll be investigating that later.

[Acill]

Does any of this leakage happen on an A3000? I've looked and cant see any problems on mine other then the battery that I removed just in time. I have a lot of caps on the motherboard too!

[Darmaster70]

Thanks for the info Mike, wish I had an amiga repairman close to me, would like to take my 4000 in and run some tests on it. Please let us know what the final diagnosis is on your machine.