Re: diag cartridge

From: Rob Clarke <>
Date: Mon, 22 Oct 2012 00:13:49 +0200
Message-ID: <>
The harness on Peter Schepers site is for the 'official' diagnostic 
cartridges distributed by Commodore. I'm not familar with the Roßmöller one.

The 'active elements' in the user port are not actually needed, so it 
may still be functionally equivalent. IIRC, the active elements are a 
pair of 4066's used to connect the lines together across the joystick 
ports, controlled by one of the I/O lines or a cassette line. After 
building one of the harnesses, my assumption was that this was just as a 
convenience to allow you to use the keyboard with the harness still in 
place. If you omit the 4066's,  and wire the joy ports directly, the 
diagnostic performs all the tests correctly but you have to remove it to 
be able to use the keyboard.


On 20/10/2012 23:57, wrote:
> On 2012-10-07, at 18:02, wrote:
>> Once in the good old times I had a cart (bought from Roßmöller I believe - although I am not sure if it was their invention) that I used to test the 64s. It was a cart and a set of plugs to connect to all the ports (KBD, USER, CASSETTE, SERIAL, CONTROL). After powering up it tested the ports, RAM etc, giving beeps upon completing each test. I found all the plugs but I can't seem to be able to find the cart itself. As I believe it was a simple ROM cart, I am looking if someone could send me the dump so that I could make myself a new one? I googled quickly but it is not the same as:
>> There are e. g. no active elements inside USER PORT plug. Software looked differently too.
> Software looked like a newer version of:
> with different colours and sounds after each test, denoting success/failure

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Received on 2012-10-21 23:00:05

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