erphi AFDC2 Diskdrive Controller for Apple II
    ( Basic page about Teac 55F ) 		   Page No.:H089b
 
         
     

 		  
   
         
     
 Pictures of the modified Teac 55F drives  
   

 

  
         
      Details of Teac 55F modifications 
The modification of the Teac 55F drive split apart in 2 steps:


1) the modification to enhance the read/write compensation for use with the Apple II:

  a) add ceramic capacitor of 150 picoFarad between pin 9 and pin 10 of the pinterminal.
  b) add at L1 a shortcutting bridge between its pins.
  c) add at the IC 7358-00 a shortcutting bridge between its pins15 and 16.

  d) cut/truncate the trace that leads to pin 15 of the 7358-00 IC.


2) the modification to enable switching between 40 track mode and 80 track mode:

    locate the position of not populated resistor R14 and insert switch and 10 Ohm resistor
     to the solderingpads.

 

  
     
   
 
         
         
     
 Shugart-bus Floppycable  In former days it was common, that cables did not have a partial twist. But in the days when IBM introduced its PC to the market it became common to distribute that cables with the inner twist. The twisted cablepart only contains the drive select signals and because the factories wanted to save time setting the Jumpers the cable had the purpose to determine the drives by position at the cable and all drives have been distributed with Jumpers set to Drive 0. If you use a "straight-
through" cable without twist you must set drive ID by setting the correct driveselect jumper to either DS0 or DS1.
 
         
         
     
   
 
         
         
         
         
         
         
     
     
                  
 
      Circuitplan of the TEAC 55F  
     
                      
   
 
       
      

      		  
 		             

 		  
 
         
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