Amiga 4000 sound problem

[Framiga]

Hi  manicx

IIRC the left RCA female connector, has a mechanical switch inside.

Try to move a bit the male RCA during playback.

If the noise stops, could be a defective RCA connector or a lack GND welding.

All the above . . .if you are lucky :-)

Ciao

-edit- sorry, no switch inside the connector, anyway if it isn't a mechanical failure, faulty capacitor could be the problem (as already said by xeron)..

[Framiga]

@ manicx

so . .locate the U403 chip (the small chip in the photo LM833).

Follow the line from pin n.1 (should have a dot on the chip) and from pin n. 7.

These pins are joint directly to the C433 (22uF-16 volt).

They are by-pass filters and could be in loss.

Download the A4000 schematics and see the Audio picture.

A4000-Schematics

Ciao

[Framiga]

by manicx on 2003/10/6 12:42:19

Just a wee question guys. Are these the two C433s? I think they are but need a second opinion just in case

ermm! . . .i apologize with you for my wrong previous post.

Yes they are the 2 C433 polarized electrolitic capacitor (strange package).

I've read yesterday, to replace it, with 2 NOT polarized capacitors (22uF-35 volt).

Ciao

[Framiga]

Hi manicx

but, sorry . . you want to send an A4000 from Greece to NZ??

Here in Italy, there is still "Logica snc" di Casonato G.Guido who has designed and produced the Amiga Hardware/software diagnostic gear.

Commodore also was interested to his diagnostic hardware.

All us in Italy, send him our broken boards (AFAIK all models). He is cheap and honest.

Let me know if you want the address.

Ciao

PS- usually, he wants only the mobo.