Conference hydra::amiga_v1

    
    I decided to give it a try, I checked what is available as 68000 cpu
    around here and found that the fastest 68000 available around is the 
    MC68000p12 it is rated at a nominal 12 Mhz and is also known as
    the 68000BPC.  The price is around CDN$20.00 (US$16.00).
    Below there is the 68000PC at around CDN$12.00
    and the 68000APC (different package(?)) at around CDN$18.00
    Both those models are 8Mhz version.
    
    I assume the "12" in MC68000p12x is for 12 Mhz.
    
    I should get the parts next monday, I'll keep it posted for those
    interrested.
    If it doesn't work, I'll be the one that wasted $20.00...
    
    Vince.

Let say I tried to make it work.
It just doesn't.   With the 7.14Mhz, it works the same as with
the normal MC68000.    If in 14.3Mhz mode, the screen react
quite funny,  sometimes it stay green (Ram PE) and sometimes
it gets dark grey, but stay there.

Now the chip I used was the MC68000BPC (68000P12).  The "A"
version (68000P12A) is not available, or unknown here.
    Do I have to use a MC68000P12F ? as stated in .0???

Nevertheless, I also tried, without conviction a xtal of 10.0Mhz
(of course unsynchronized with the other clocks) and it also acted
almost the same way as the 14.3Mhz scheme.

My Amiga (B2000) definitely doesn't like the CheapAcc project.

I also tried to remove the expansion Memory, HD ctrlr and the 
BridgeBoard options without any change.

Perhaps on A500 it does work? Out of about 15 amiga owners I know,
not one have a A500.  All A1000/2000/2500 owners...

If anyone has tried it succesfully, let me know, please.

The only 2 things that I am still unsure are:
    1) the chip (rev A or rev F???) might be a must?
    2) the lenght of the clock wire on a 2000 cannot be smaller than
       about one foot.  (from the Xtal to the switch to the CPU)
       Is this too long for a 14MHz signal? 
    
    
Vince.

    I was going to try it with a 16Mhz 68000 .
    Am I to assume that 12Mhz is required ??
    
    
    			Pete
    
    ( a Amiga 500 owner )

    This seems to be the problem.  How one can find a 16Mhz 68000?
    
    Dealers around here only know of, and sell the MC68000p12, which
    is rated 12Mhz.
    
    Anyone knows a place (mail order) where they sell a TRUE 16Mhz?
    if that beast really exist... (is it called MC68000p16?)
    
    BTW: The frequency to feed it is 14Mhz, so I am not sure a
         12Mhz can handle it, does it?

    Part # for a 16MHz 68000 is   MC68000P12F
                                            -
      
    The sample I am holding in my hand as I type this has 16MHZ printed
    right below the part number...

    
    Look for the chip to contain the following:
    
                                  (M)
                              MC68000P12F
                                 16MHZ
                               0B26M8838    <--   Date code 
    
    
        
    John

    
    Hi John,
    
    Where did you get it from?
    Active component don't have it their catalog ('90)
    I also checked in IC Master 1990 edition and it is not listed.
    They list EF68000-16 (SGS-Thompson) but no Motorola 16Mhz version.
    
    Anyway, they refused to order it for me, since they don't have
    it on their computer.
    
    Any mail order place where I can order?
    
    Vince.

    I had the chip lying around in an old accelerator module I don't
    use.  I'd give Motorola a call for the local distributor in your
    area.
    
    John
    

    I checked with the publisher of the Disk magazine in which this thing
    first saw the light of day. There is an update to the article and I'll
    try to get hold of it and post it here. 
    
    From memory.......
    
    1.	The part # is MC68000p12F (16.67Mhz gizmo)
    
    2.	Dont use ribbon cable to go to the switch (inter-electrode
    capacitance etc..) unless you separate the conductors.
    
    The publisher assures me that this Does work . I intend to contact the
    Author and verify.. I also intend to give this thing a shot, as soon as I
    can get hold of the chip.
    
    Glenn.
    
    BTW, The same guy has developed an el-cheapo in-box memory expansion
    for A500's. (looks like up to 4Mb)

    
    Re:.7
    
    I did just that (called Motorola) and they gave me 3 places where
    I may find the chip.  1 of  them was the place where they refused
    to order, the second one sells only to retailers and the 3rd one
    is Hamilton-Avnet.  Being a DEC OEM, I have some contact there.
    The only problem is that I have to order a minimum of 3 (to make
    it over $50.00).  He would sell them at CDN$18.00 each.
    Delivery is anywhere between 3 to 14 weeks...
    
    Still looking for alternate source.
    
    Vince.
    

    Hi,
    	The reason they did not want to supply you with one from
    (sgs-Thompson) is because they insist on a minimum order of
    180 ....
                                               
    			- Pete -
    
    PS  Looking forward to the memory project..

    for more info on the project refer to FRSOLD::AMIGA_HARDWARE NOTE 425.
    
    Looks like somebody had a win!
    
    Glenn.

    Refering to the Amiga_hardware notefile (#425), it is still sort of
    scary.  The floppy problem worries me.
    
    I ordered 4 chips (2 for A1000 and 2 for A2000).  I hope my 3 
    partners won't shoot me if that doesn't work.   Glenn, in some
    previous note mentions he can have some contact with the designer
    of this hack.   If he could post the "patch" for the drives that
    would be very nice of him.  
    This "patch" is mentionned in the textfile given with the hack.
    
    Thanks, Vince.

Hi,
    
    	Re   The Floopy Patch ... I got this off of usenet...
    
            <<< FRSOLD::IS$NOTES:[NOTES$LIBRARY]AMIGA_TECH.NOTE;3 >>>
                      -< comp.sys.amiga.tech - postings >-
================================================================================
Note 3696.0          Reducing floppy step rate: my solution           No replies
FRSOLD::ZIMMERMANN "eklektik!danbabcock"             40 lines  28-APR-1990 08:19
--------------------------------------------------------------------------------

Path: shlump.nac.dec.com!decuac!haven!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!usc!apple!vsi1!zorch!ditka!nfsun!eklektik!danbabcock
From: danbabcock@eklektik.UUCP (/dev/ph1)
Newsgroups: comp.sys.amiga.tech
Subject: Reducing floppy step rate: my solution
Message-ID: <2405@eklektik.UUCP>
Date: 25 Apr 90 01:34:53 GMT
Reply-To: danbabcock@eklektik.UUCP (/dev/ph1)
Organization: Computers, Gerbils, and Games in the Basement, Pgh, PA
Lines: 30
 
gfre@pawl.rpi.edu (gregory m stiegler) wrote:
 
>Ok, now for the big question. Does anyone have a way to slow the drives
>down? The circuit seems to work fine but you can't boot.  I assume the E
>clock is being sped up along with the processor. Any fixes for that?
>--==Niemand==--
>gfre@pawl.rpi.edu
 
- all the following assumes kickstart 1.3 -
 
There is a simple way to slow the drives down. Just replace the longword
at address $fea176 (which used to be $6d000024) with $6d24e388. What could
be easier?
 
If you can boot (perhaps with an autobooting hard drive) but still want
to slow the drives down - and can't modify kickstart - there is also a
software solution. In fact, I wrote a program to do it. The program
actually has the complete trackdisk.device code imbedded in it - with
all absolute addresses converted to assembler labels! Then I simply pull
a NoClick-like stunt to redirect the trackdisk tasks to the RAM-resident
code. This also allows me to fix the infamous RawRead/RawWrite bug.
If you want a copy of the program, please send me a disk (email from this
site seems to be lost in a black hole...) to the address below, or contact
me on People/Link.
 
-- Dan Babcock
1106 Jefferson Road
Pittsburgh, PA 15235
Phone: (412)-373-1753
People/Link: DANBABCOCK
    
    
    			- Pete -
    
    Usual disclaimer applies... untested by me or unsupported by me...
    

    Just to throw another fly in the oitment.  Is their such a thing as a
    16MHz 68010?  I have already built the circuit with spare stuff around
    the attic.
    
    Alan

    
    I finaly got my 68000 at 16Mhz.  I realy tried, shaped the pulse,
    slightly play with the phase etc, but it never worked.
    The best I got was the dark grey screen in the startup.
    
    	If you have a Amiga 2000, don't waste your money on a 16Mhz chip.
    Some friends also tried on a A1000, no luck there either.
    I could not experiment on A500, but be sure that it doesn't work
    on a A2000 (or B2000).
    
    Vince.