Re: commodore plus 4 without sound...

From: Gerrit Heitsch <>
Date: Thu, 15 Mar 2012 17:34:06 +0100
Message-ID: <>
On 03/15/2012 12:46 PM, didier derny wrote:
> Hi,
> it was the cable working with my sx64.
> I checked the signal directly on the rca connector.

You might want to check the signal directly at TED (Pin 33 is Sound 
output) and if it's present there, check the simple amp that is between 
TED and the DIN socket you plug your video cable into.

The circuit is uses only one transistor (Q3) and can be found in the 
schematics on the page with the modulator. There are a few electrolytic 
capacitors in the signal path, one of them might be dead/dry.

On the PCB the circuit is located right next to the keyboard connector. 
One side of R10 (1KOhm) is directly connected to TED's sound output. 
Checking the signal there might be easier.

Hope this helps


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Received on 2012-03-15 17:00:05

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