Double Trouble

The hack to accelerate your Amiga to 14MHz has been published in countless articles,  but I may as well include a brief description of it here. The hack involves removing the original 68000 from your Amiga and substituting a  version rated at 16MHz confusingly called the 68000P-12 the Motorola chips have 16MHz stamped on them,  but the SGS-Thompson clones do not  The clock pin is bent out and soldered to the output of a divide-by-2 counter whose input is connected to the base 28MHz clock. THIS MODIFICATION SHOULD BE INSTALLED WITH A SWITCH If not,  you WILL not may find that some games will refuse to load because they use timing-dependent loaders. 
        
Aside from the problem mentioned above,  the only compatibility down-side to this modification is that some floppy drives will not handle the increased step rate. If you find that your drives give read write errors at the high speed,  you can either replace them or run a program called DFDelay to slow down the step rate. df0 will not work,  you have a problem. Try swapping df1 for df0  - to do which you will need a Commodore df1 The mechanisms used in the old A1010 drives are EXTREMELY reliable and much quieter than the new rubbishy things if you have an A1010,  you can be fairly certain that itwill support the new speed 
        
To perform the mod,  remove your old 68000 and embed it in a perspex block for future reference. Now rig half of a 74S74 dual D bistable as a divide-by-2 counter. Connect the input of this to a convenient take-off point of the 28MHzclock line on the motherboard use pin 34 of Agnus,  but anywhere will do. Now bend out pin 15 of the new CPU and solder a wire to this pin. Take a piece of stiff telephone wire,  strip approx. 5mm of insulation from one end, and stick this end down pin 15 of the 68000 socket. 

Insert the new CPU in the socket and verify that pin 15 is well clear of the wire in the socket. Now wire a SPDT switch as follows:
 
                                            BACK VIEW 
                                When held as shown UP 14MHz,  
   To output of divide-by-2 counter+DOWN=28MHz 
                 To pin 15 of 68000  
  To wire in pin 15 of 68000 socket 
 
The 74S74 should be mounted somewhere convenient[1;35m;[0;37m I break off all the unused pins,  bend the remaining pins out,  and stick the chip on top of one of the data path IC this has the advantage of allowing me to take power directly off the existing components rather than stringing yet another pair of wires through the machine. 
        
If you only have chip and slow memory then your machine will run at
approximately 150% normal speed mon CPU-intensive operations DMA rates will be unchanged  If you have true fast-RAM then code running from fast-RAM will execute at close to 200% of normal speed. Try placing a large perpective brush with anti-aliasing HIGH in DeluxePaint III and you will see the speed increase.