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Old 10 September 2008, 18:20   #1
lennonlives
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Very odd sound problem with an A1200 - help needed!

I bought two A1200s from England to add to my Amiga collection. Upon playing games on them I noticed that one sound channel was considerably louder than the other one. I don't have that problem with my other two A1200s (one is a brand-new Escom, the other one is a brand-new Commodore). Fiddling around with the cables didn't reveal any loose contacts. I used the same monitor-sound-setup for every machine.

Have you encountered this problem before? Do you have any clue what could be the cause of this and if my English A1200s are somehow damaged? Another info: Both boards are rev. 1.D4 and are non-expanded.

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Old 10 September 2008, 20:53   #2
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No ideas?
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Old 10 September 2008, 21:00   #3
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Originally Posted by lennonlives View Post
No ideas?
lol, give people chance to reply. With different timezones and that, it may take a day for a reply.
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Old 10 September 2008, 21:01   #4
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caps?
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Old 10 September 2008, 23:25   #5
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Hehe, true.

Not sure about the caps idea. I don't know much about these things so I just attached a photo I took. Looks okay to me, but feel free to correct me.
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Old 11 September 2008, 04:26   #6
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The capacitors don't need to leak to make a mess.

Just change the pair. The values are 22uF x 16 or 25V (prefer 35V no-polarized versions) and they are very near the audio out jacks.

If you can't solder, ask for someone near you who can.
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Old 11 September 2008, 08:48   #7
lennonlives
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Very good, thx for pointing that out to me. You mean these capacitors?

I noticed another problem with one of the A1200s bought. The picture through composite is bluish, but fine through RGB. What might the cause of this and how could I fix it?
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Old 11 September 2008, 10:24   #8
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Yep, those are the culprits! Swap those little bastards for two no-polarized 22uF x 25V (35V if there is enough space).

Image tend to blue only in composite/RF? Problem in the area of the video encoder. Check for bad solder on resistors around it. The encoder is the CXA1145 chip, right "under" the power connector area. The chip itself could be the knackered one, here. Ask for help on solder SMD components if you don't have the skills/equipment.
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Old 11 September 2008, 20:26   #9
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Quote:
Originally Posted by lennonlives View Post
Very good, thx for pointing that out to me. You mean these capacitors?

I noticed another problem with one of the A1200s bought. The picture through composite is bluish, but fine through RGB. What might the cause of this and how could I fix it?
rkauer is right, this SMD caps are evil. Cause they leak underneath and dont always show.

I remember sony used to use cheap SMD caps in their camcorders. They would expect you to change over 50+.
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Old 14 September 2008, 14:41   #10
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You guys are brilliant! Replaced the audio caps and everything is fine again

No progress on the video though.
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