Re: Commodore 65 and DIN8 cable

From: Michał Pleban <>
Date: Wed, 02 Mar 2016 21:42:32 +0100
Message-ID: <>
Hello! wrote:

> You'd need to remove the filters first. Then you could jumper the signal over. But if the U1 is removable then you should be able to make the lines "open" and measure thoroughly all of them.

OK, unsoldering stuff from a C65 motherboard is a last resort :-) So
let's play with the oscilloscope first:

This is the DISK_RD signal without any cable:

Here it is with 30cm cable attached:

As you can see, the rising edge of the signal trails off a bit longer.
This is even more visible with a 1m cable:

Here it is really bad. I understand that the signal rises more slowly,
thus the decoder sees logical "0" longer than it should and throws errors.

Does it make any sense to you? Why a cable might introduce such effect?


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Received on 2016-03-02 21:01:30

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