From: slbfn@cc.usu.edu
Newsgroups: comp.sys.amiga.hardware
Subject: SUMMARY:  16MHz A3000 to 25MHz  (!)  Hardware "Hack"
Date: 12 Aug 92 15:11:40 MDT
Organization: Utah State University
Summary: How to upgrade a 16MHz A3000 to 25Mhz.
Keywords: 16MHz, 25MHz, Amiga, 3000, hardware, hack, upgrade, speed, increase



                         HOW TO (MAGICALLY) TRANSFORM A
                           16MHz AMIGA 3000 TO 25MHz   
     ---------------------------------------------------------------------


Disclaimer:  Anyone wanting to upgrade their 16MHz Amiga to 25MHz
             is "on their own".   I, nor anybody mentioned in this
             article will be held responsible for damage inflicted on
             their (or anybody elses) machine(s) for any reason(s).  
                     
                 *********************************************
                 *** USE THIS INFORMATION AT YOUR OWN RISK ***
                 *********************************************

             Anybody wishing to upgrade using this method should be
             **VERY** experienced at using solder/de-soldering equipment.
             The 68030 CPU and 68881 FPU are *VERY HARD TO REMOVE* (!)

             Remeber, break your Amiga, and it's YOUR FAULT, not mine!!!
             No guarantee is suplied with this hardware hack.  If it doesn't
             work, you're on your own.  Nobody but yourself can be held
             accountable.


Special Thanks To:  Dave Heynie.  Without him, this simply wouyldn't be
                    possible. (!)  Thank you, Thank you, Thank you!!!!!

             

Procedure:            

      (1)  First off, disconnect the power!  :)

      (2)  Remove the 68030 CPU.  This is definately *NOT* an easy task!
           You must carfully desolder all the pins.  (The 68030 is packaged
           in a very fine-pitched 128 pin PQFP.)  Make sure you remove all
           solder.  Don't be messy.  If you don't know how to do this, don't!
           It is very easy to screw up your motherboard.  Please make sure
           you know what you are doing.

      (3)  Place a 25MHz 68030 CPU in the 16MHz CPU's place.  You may wish
           to use a socket so you don't accidently damage the processor.  
           Soldering is a lot easier than desoldering, but if you don't know
           what you are doing, don't atempt to do it.  Also, make sure you
           don't get an MMU-less CPU.
     
      (4)  Remove the 68881 FPU.  Do this the same as in step 2.  Again,
           make sure you know what you are doing.  The 68881 may not have
           as many pins, but it is still very difficult to remove.

      (5)  Place a 25MHz 68882 ( NOT A 68881 (!) ) FPU in the 16MHz CPU's
           position (just like in step #3).  You may wish to use a socket.
           A 68882 FPU is electronically and pin compatable with the 68881,
           except for a 50% increase in some calculations.
 
      (6)  Now you must remove the 32MHz crystal and replace it with a
           50MHz counterpart.  (32/2 = 16MHz ; 50/2 = 25MHz)

      (7)  Next, ITS JUMPER TIME!! (Hurray!)

               Jumper    Position   Function
               -------   ---------  ----------------------------
               J151      1-2        ROM Timing
               J152      1-2        ROM Timing
              
               J100      1-2        Quadrature Clock Phasing
               J851      2-3        RAM Controller Speed Jumper

           Please verify that these jumpers are in these positions
           before continuing.

      (8)  Verify all steps and turn on the power!


Also:          Ramsey (the DRAM controller) is designed to work with 80ns
               parts.  70ns parts will work, but don't pay anymore for
               higher speed parts.  You won't see ANY increase in speed,
               and there will not be an increase in introduced wait states.

               There are no different speed Agnus.  All are rated at the 
               same speed.   The same Agnus is found in the 16MHz Amiga
               as well as the 25Mhz Amiga.

Well, have fun!  

-- Travis Carter
   slbfn@cc.usu.edu