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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: TjLaZer on September 01, 2004, 05:33:19 AM
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Has anyone heard about the A600 having bad sound? Distorted a bit when turned up real loud? Not too bad but noticible on higher levels. Could there be something wrong going on? I also have another A600 that works but sound is dead...
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Im sure my amiga 600 back in the day had the same problem of distorted sound. maybe the RCA cable has gone bad or maybe just sounds the way it produces through the paula? :)
Yea, but either then that, i wouldnt know what the problem would be.
@tjlazer
I had sent you a few Private Messages regarding the Video toaster,but ive heard no replys from you. :-( :-(
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If I turn my speakers all the way up I can hear the CPU working. It's
almost like morse-code!
Surely the RCA phono outputs should be clean of all this interference?
I can't blame the speakers if they amplify noise coming from the
motherboard... pity help me if I used an amplifier instead of PC
speakers!
Could it be another capacitor issue?
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I have recently that kind of problem that my A600 had a noise like "wrrrmmm" (about 50Hz) every time when I switched on. It turned out that the external floppy died. After I've disconnected the external floppy the noise disappeared.
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Hyperspeed wrote:
If I turn my speakers all the way up I can hear the CPU working. It's
almost like morse-code!
Surely the RCA phono outputs should be clean of all this interference?
It's a common problem when you have the Sound chip on the same board as the CPU :-(
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The louder I turn the sound up the more distorsion I get. Well what do you expect, I got this from the infamous DoomMaster himself. I was smart though and I drove down to pick this up myself. He even charged me a $5 eBay handling fee if you believe that.
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Dumb quesiton, but are CIAs socketed on the 600? It seems to me that whenever just about anything goes wrong, it's a good idea to swap the CIAs and see if anything changes.
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No CIAs are surface mounted! I also have two more 600's. One is DEAD and the other works fine but has no SOUND. :(
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Bummer.
I have not seen a 600 since 1994.
Hey, with so many dead 600s, you don't happen to have an internal drive to sell? I have a 1200 fully working except the internal drive.
PM me if ya do.
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@TjLaZer:
Check the two 22uF 16V surface mount capacitors in the audio-circuitry between the Paula and line-out on your A600 which has no sound.
/Patrik
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@patrik
I will have a look. What am I looking for? ;)
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@TjLaZer:
Signs of broken caps like leakage and or bulged tops. It should be the same issue as in the A4000.
/Patrik
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@TjLaZer
hmmm, I never really even considered the possibility of damage on my 600, but I thought it was just like that.............when I pump up the volume on the music I am playing that I digitized with a sampler...the Sound gets worse, i thought it was just becasue its 8 bit sound..............hmmmm, I know what I can do to prove this theory...............I will turn the volume up on a few mods and games and see what happens......I really dont think my sound gets distorted.I think its that when the volume is low....you dont hear all the hissing from sampled sounds until you raise the volume and hear the hissing more clearly.............................................................
But maybe not.Im not sure...........I will run a few tests
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@patrik
I check the MB over and it is all nice and clean!! Do those caps cause the sound to not work? Could it be the CIA or Paula?
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Check C303 and C304, I had to replace these on my A600. They provide bulk decoupling for the LF347/TL084 audio filters. Also check C324 and C334, they are all 22uF electrolytics. I used an LCR meter to check the caps were duff, though one smelt funny!
Mine had a 'black goo' spot on them.
Does the -12V of your PSU still work?
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@stedy
How do I check all those? I am not a expert in electronics. Do I check for resistance? With power off right?
Thanks
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@TjLaZer
Not easily.
You can use the resistance function of a multimeter to ascertain if the capacitor can hold a charge. All tests are done with the power off.
You may be able to test the capacitor whilst still on the PCB. Use a high range resistance function of a DVM (100K or more) and connect the probes across the capacitor. The reading should quickly rise. If the resistance does not rise, the capacitor is suspect.
After testing the capacitor, use a 1K resistor or similar to short it out, before testing the next one.
I have paraphrased things somewhat, but I hope you get the idea.