You should follow these instructions if your drive already has a Commodore parallel cable and you want to make use of it. In this case, you'll have to build an adaptor, through which you can connect the cable to the PC parallel port.

Important notes

• Don't use a PCB-mountable parallel plug for this adaptor. If you use a solderable plug, one that is usually used for cables, then you can make your adaptor significantly smaller.

• The circuitry will be on the top side of the adaptor. It is very important, however, that you'll have to connect the bottom side of the user port plug onto it, that is, upside down.

• On circuit diagrams, plugs are displayed as viewed from the back side, the solder side. Chips are displayed as viewed from above; also, see the small semicircular cut for finding the correct orientation. When in doubt, see the corresponding description on the legend page.

Construction

• One printable circuit board of about 5.5 x 3 cm

• Eight diodes (e.g. 1N4148)

• One solderable 25-pin male plug (PC parallel plug)

Step 1. Create the direct connections on the board, between the user port edge and the parallel plug. These include the following connections:

User port edge 
 Parallel plug 

     C, PB0    
   13, Select  

     D, PB1    
   12, PaperEnd

     E, PB2    
   10, Ack     

     F, PB3    
   11, Busy    

     A, GND    
18-25, GND     

To make the board single-sided, you may omit the GND connection.

Step 2. Create the diode connections on the board, between the user port edge and the parallel plug. These include the following connections:

User port edge 
 Parallel plug 

     H, PB4    
    6, Data 4  

     J, PB5    
    7, Data 5  

     K, PB6    
    8, Data 6  

     L, PB7    
    9, Data 7  

The cathodes of the diodes should be pointing towards the pins in the right column of the table.

Step 3. Build the diode bridges between the appropriate pins of the parallel plug. These include the following connections:

 Parallel plug 
 Parallel plug 

   10, Ack     
    4, Data 2  

   11, Busy    
    5, Data 3  

   12, PaperEnd
    3, Data 1  

   13, Select  
    2, Data 0  

The cathodes should be pointing towards the pins in the right column of the table.

Step 4. Solder and then glue the board between the two pin rows of the parallel plug. The top side of the adaptor, the one with the circuitry, should be leveled with the longer side of the parallel plug, the one with thirteen (13) pins.

Circuit diagram

You can find the description of all parts used on the diagrams at the legend page.

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