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Old 05 December 2008, 04:14   #1
Ideal
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A500 - very low audio out, capacitor?

I have an A500 with very low audio output.
I believe this may be related to a capacitor or something.

Basicly the audio out is too low and sounds sort of distorted.
I've been thinking it may be some dried out capacitor or something?

I read that the audio chip doubles as floppy controller. I've installed a High Density floppy in it, could this be related? Have not tried with different chip yet, may do that first. Any thoughts?
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Old 05 December 2008, 08:09   #2
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Quote:
Originally Posted by Ideal View Post
I have an A500 with very low audio output.
I believe this may be related to a capacitor or something.

Basicly the audio out is too low and sounds sort of distorted.
I've been thinking it may be some dried out capacitor or something?

I read that the audio chip doubles as floppy controller. I've installed a High Density floppy in it, could this be related? Have not tried with different chip yet, may do that first. Any thoughts?
the audio output of the A500 is by default low....lot lower than the A1200 audio output for example
but if the sound is distorted ... check for inflated capacitors...verify the audio cable.....try another audio system
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Old 05 December 2008, 13:38   #3
Ideal
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Well I know it's not the cable.. tried with different speakers designed for PC, and the RGB->TV, so not that.
It's just like as if the audio is inverted, "ding" makes "blopp" instead.
Will check the capacitors.
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Old 05 December 2008, 19:28   #4
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Why worrying testing the capacitors? They are all 20+ years old!

Swap all of 'em, they are just 15 units on the A500 boards (any version). Anyway, the audio capacitors are C324 and C334. They are 22uF and 25V (or more).

Ask me for the full capacitor list if you want to make the right thing.
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Old 06 December 2008, 04:52   #5
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Please do go ahead and list them all as I would love to replace them.
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Old 06 December 2008, 15:35   #6
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Originally Posted by rkauer View Post
Why worrying testing the capacitors? They are all 20+ years old!

Swap all of 'em, they are just 15 units on the A500 boards (any version). Anyway, the audio capacitors are C324 and C334. They are 22uF and 25V (or more).

Ask me for the full capacitor list if you want to make the right thing.
ya I 2'nd that ! my 1200 was almost toast when I realized the audio caps had leaked...$5 and 30 minutes of work solved the problem for at least another 20 years..hopefully
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Old 06 December 2008, 18:00   #7
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2x 3300uF x10V
6x 47uF x 16V
4x 22uF x 25 or 35V
2x 100uF x 16V
2x 10uF x 35V or 50V

Always remember: those capacitors are polarized! Don't solder 'em backwards or they will loose functionality.

Higher voltage type work OK, but may not fit on the board.
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Old 06 December 2008, 23:35   #8
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Allright. I ordered three sets, so I can do three boards.
Hope they are the same values on 500+ also.

Do you happen to also know the values of all the caps on the A4K motherboard?
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Old 07 December 2008, 01:35   #9
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I found this list of parts on Amibay. I don't think this list includes the processor board.

Code:
 
Description              Jameco#      Item#  Quantity
Cap,Tantalum,100uf,6.3V  TM100-VP-R   33702  1
Cap,Tantalum,47uf,16V    TM47/16-VP   94124  10
Cap,Tantalum,22uf,16V    TM22/16-VP   94095  5 
Cap,Tantalum,10uf,35V    TM10-VP-R    33691  1
Cap,Tantalum,4.7uf,35V   TM4.7-VP     33807  1
Cap,Tantalum,4.7uf,25V   TM4.7/25-VP  94044  1
There's some help on this website http://amiga.serveftp.net/audio_repair.html on repairing the audio on the 4000. This helped me restore the sound on my 4000D.

Dave G
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Old 11 November 2009, 15:18   #10
Lockon
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@rkauer

I've just dissasembled my 2 "production" Amigas. Caps list is pretty different from what I can see it.

Rev6A

2x 3300 uF 10V
1x 470 uF 16V
6x 100uF 16V
2x 47uF 16V
4x 22uF 35V
2x 10uF 50V


Rev8A

3x 1000uF 10V
6x 100uF 16V
2x 47uF 16V
4x 22uF 35V
2x 10uF 35V
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Old 12 November 2009, 04:28   #11
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C= going cheap again...

1k uF instead 3.3k uF... Typical.
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Old 12 November 2009, 08:25   #12
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Hold on, I know I have somewhere a Rev5 coming for annual 3-day powercycle/disk ordeal. I hope I won't find any of 4.7k's inside
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