Eagles Nest BBS 2/Eagles_Nest_Mac_Collection_Disc_2.TOAST/Tips & Tricks/25mhzIIsi/25 mhz si

Internet Message Format | 1992-10-10 | 18KB

From news.service.uci.edu!usc!wupost!uunet!stanford.edu!CSD-NewsHost.Stanford.EDU!csd-newshost.stanford.edu!gjohn Fri Oct  9 22:45:37 PDT 1992
Article: 33577 of comp.sys.mac.hardware
Newsgroups: comp.sys.mac.hardware
Path: news.service.uci.edu!usc!wupost!uunet!stanford.edu!CSD-NewsHost.Stanford.EDU!csd-newshost.stanford.edu!gjohn
From: [e-mail] (George John)
Subject: HOW TO UPGRADE YOUR IIsi TO 25MHz
Message-ID: <[e-mail]>
Sender: [e-mail]
Organization: Computer Science Department, Stanford University, CA, USA
Distribution: usa
Date: 8 Oct 92 02:30:05
Lines: 180


HOW TO UPGRADE YOUR IIsi TO 25MHz

DISCLAIMER: Performing this upgrade WILL void your warranty.  It
involves desoldering an oscillator from the motherboard and replacing
it with a new one.  For all I know, performing this upgrade will fry
your CPU and people will sing songs about how dumb you were for doing
it for generations to come.

Recently many people have been asking about how to speed up their
IIsi.  I upgraded my IIsi 2 or 3 weeks ago.  It cost me $4.  My
computer is now 25 to 50% faster.  I have had no problems with my
computer since then.  The upgrade involves desoldering the 40 MHz
oscillator and replacing it with a 50 MHz oscillator, thereby
increasing the speed of the CPU from 20MHz to 25MHz.  One of the big
things I've noticed is the graphics speedup -- graphics speed in 8
bits of color is faster now than monochrome was before!

Here's the story on performance.  Numbers below are speed relative
to a mac classic, so bigger is better:

                BEFORE        AFTER

CPU                5.24        6.69
Graphics            6.17        7.64
Disk                1.30        1.34
Math                5.45        6.91
Overall Performance        4.75        5.92  (25% faster as expected)

KWhetstones            6.33        7.97
Dhrystones            5.11        6.62
Towers                4.42        5.69
Quicksort            5.01        6.43
Bubble Sort            5.88        7.50
Queens                5.83        7.33
Puzzle                5.61        7.22
Permute                5.33        6.55
Fast Fourier            4.27        5.39
F.P. Matrix            4.53        5.70
Int. Matrix            4.85        6.09
Sieve                6.53        8.35
BENCHMARK AVG.            5.31        6.74

Graphics:
1 bit (mono)            1.72        2.15
2 bit                1.83        2.31
4 bit                1.92        2.47
8 bit (256 colors)        1.22        1.89 (50% FASTER!!!!)
Avg:                1.67        2.21


WHY THE UPGRADE WORKS:
    (I have not done the technical investigations myself -- I'm
just echoing previous reports I've seen on the net.)
    The IIsi was announced back in '90 as basically a poor man's
IIci.  The main difference is the lack of nubus slots inside.  If you
think about it, it makes engineering sense to reuse as much of the
IIci's design as possible.  I've heard that the chips that run off the
cpu clock were all designed for 25MHz performance for the IIci.  The
reason apple went with a 20MHz cpu in the si seems to be mostly
marketing -- would you buy a ci for $3500 if you could buy a 25MHz si
for $500 or $1000 less?  So it seems that the si was "crippled" for
marketing reasons by putting in a 40MHz oscillator package, thus
making the cpu run at 20MHz instead of the ci's 25MHz.
    Again, I have no idea whether the above paragraph has any
basis in fact.  It's just what I've heard.  For all I know, the IIsi
chips were designed to run at 20MHz which resulted in considerable
savings which was passed on to the consumer.  All I can say is that
my computer has worked okay for the last few weeks at 25 MHz.  It's
usually on at least 6-8 hours per day.


DETAILS ON THE UPGRADE:
Upgrading your machine is a pretty simple operation, if you've used
a soldering iron before.

Tools required: Soldering Iron.  And something small to pry with.

Parts required: 50MHz oscillator package, 4-pin socket (14-pin size
but just has pins in the 4 corners) for the oscillator (just in case
you want to be able to go back to 20MHz for some reason).  I bought
these parts at Fry's electronics in Palo Alto, CA.  The oscillator
costs $4, the socket was 11 cents.  The phone number for Fry's is
415-496-6000.  Don't know whether they do mail order or not.

Procedure:
Take the motherboard out of the case.  This is kind of fun actually.
The mac IIsi is a really well-designed machine from an assembly-time
standpoint.  No screwdriver involved in disassembly.

Open the case.  (It lifts off from the back.)

Remove the floppy drive.  (Unplug it from the motherboard and lift it
out of the case while holding in the 2 small latches on the sides of
the floppy drive.)

Remove the hard drive.  (Same thing, unplug the scsi cable from the
motherboard and the power cable, then just lift it out.  In this case
the latches on the case need to be pushed out so you can remove the
drive.)

Remove the fan.  (You have to squeeze the plastic on the sides near
the bottom and back of the case to get it out.  Just lift it up while
squeezing.)

Remove the power supply.  (Again, just lift up while holding the two
latches in on the sides of the ps case.)

Remove the simms.  (They snap out easily.  Again there are little
metal latches that hold them in place.)

Remove the motherboard.  (Pull it towards the front of the case while
pushing the two tabs on the case that hold it in place to the outside.)

Warning:  The soldering iron stuff comes next.  Fooling around with
your IIsi motherboard is not a good first soldering-iron project.
You can do all sorts of awful things to computer chips by making them
too hot, and soldering irons are kind of hot, sooo...

Desolder the 40MHz oscillator.  You should see a row of little silver
boxes just to the right of the simm slots.  The one closest to the
simms should say 40.000 MHz on it.  This is the guy to desolder.
You could really screw things up here, so be careful with the soldering
iron.  I removed mine by working on a pair of pins at a time -- get one
pin hot enough to melt the solder, then quickly switch to the adjacent
pin and heat that pin while prying the oscillator away from the motherboard
on the other side.  Switch back and forth between the pair while prying
until one side has been completely detached from the motherboard, then
work on the other side.

Put the socket into the holes where the oscillator used to be.  This
is the same thing in reverse -- instead of prying off the old chip
you're pushing in the new socket.  I didn't want to bend the pins, so
I tried to push them all in just a bit at a time.  Warm up the solder
in one hole in the motherboard until it's melted and push that pin of
the socket in a bit, then repeat going around clockwise until the
socket is set firmly, all the way into the motherboard.

You're done.

You might want to put your 40MHz oscillator into the socket first,
just to make sure your computer still works.  Be sure to put it
back in the same way it was facing when you took it out.  On my
computer, all of the oscillators have 3 rounded corners and one
square corner.  The square corners are all facing the bottom right
on my motherboard.

Put the computer back together.  See if it works.

If it does, congratulations.  Pop the 40MHz crystal out of the socket
and put in the 50MHz crystal.  (Do this while the computer is off, of
course!)  Fire up your computer and run a benchmark.  Giggle like a
maniac.

Now, one concern of running the cpu 25% faster is that P=(I^2)/R
(power equals current squared divided by resistance) and
we've just made increased the current by 25%, which will increase
the power by... well... at least 25%.  So the cpu will be getting
hotter and you might want to consider a heat sink.  These are big
metal weird-looking things designed to soak up heat and disperse it
into the air.  You can glue one to the top of your cpu.  I believe
there is such a thing as thermal-conductive epoxy, but since I
haven't put a sink on my cpu yet I can't tell you exactly what they
call this stuff, or what type of heat sink to ask for.


Credits
-------
I was far too wimpy to be the first guy in the world to try this.
That distinction goes to <forgot his name> at CalTech and Paul A. in
Australia, who was kind enough to send me his procedure for performing
the upgrade.

Good luck.  May the Quartz be with you!

--George John






From news.service.uci.edu!usc!wupost!uunet!decwrl!pa.dec.com!rdg.dec.com!decvax.dec.com!decvax!strange Fri Oct  9 22:46:33 PDT 1992
Article: 33584 of comp.sys.mac.hardware
Newsgroups: comp.sys.mac.hardware
Path: news.service.uci.edu!usc!wupost!uunet!decwrl!pa.dec.com!rdg.dec.com!decvax.dec.com!decvax!strange
From: [e-mail] (Steve Strange)
Subject: Re: HOW TO UPGRADE YOUR IIsi TO 25MHz
In-Reply-To: [e-mail]'s message of 8 Oct 92 02:30:05
Message-ID: <[e-mail]>
Sender: [e-mail] (Usenet News System)
Nntp-Posting-Host: squeeze.zk3.dec.com
Organization: Digital Equipment Corp.
References: <[e-mail]>
Distribution: usa
Date: 8 Oct 92 09:47:17
Lines: 28

In article <[e-mail]> [e-mail] (George John) writes:

   Desolder the 40MHz oscillator.  You should see a row of little silver
   boxes just to the right of the simm slots.  The one closest to the
   simms should say 40.000 MHz on it.  This is the guy to desolder.
   You could really screw things up here, so be careful with the soldering
   iron.  I removed mine by working on a pair of pins at a time -- get one
   pin hot enough to melt the solder, then quickly switch to the adjacent
   pin and heat that pin while prying the oscillator away from the motherboard
   on the other side.  Switch back and forth between the pair while prying
   until one side has been completely detached from the motherboard, then
   work on the other side.

Thanks for the info!  I just might try this.  One thing about this
part tho':

I would strongly recommend using solder wick for the removal of the
crystal.  This will be a lot faster and probably safer (won't have to
heat up the board etch nearly as much).  Also, then there won't be any
solder already on the board when you go to put in the socket, so that
procedure will turn into a 30-second affair rather than a number of
minutes.  And again, this will be more gentle on your board.

    Steve






From news.service.uci.edu!usc!wupost!zaphod.mps.ohio-state.edu!darwin.sura.net!gatech!purdue!mentor.cc.purdue.edu!noose.ecn.purdue.edu!gn.ecn.purdue.edu!jess Fri Oct  9 22:47:13 PDT 1992
Article: 33588 of comp.sys.mac.hardware
Path: news.service.uci.edu!usc!wupost!zaphod.mps.ohio-state.edu!darwin.sura.net!gatech!purdue!mentor.cc.purdue.edu!noose.ecn.purdue.edu!gn.ecn.purdue.edu!jess
From: [e-mail] (Jess M Holle)
Newsgroups: comp.sys.mac.hardware
Subject: Re: HOW TO UPGRADE YOUR IIsi TO 25MHz
Message-ID: <[e-mail]>
Date: 8 Oct 92 15:32:33 GMT
References: <[e-mail]>
Distribution: usa
Organization: Purdue University Engineering Computer Network
Lines: 7

I know a couple of people who have done similar things with other
machines, with no problems to the best of my knowledge.

One sped a IIfx up to 50MHz, the other sped a Quadra 900 up to 33MHz
(ala 950).  They DID add heat sinks and more powerful fans.

Jess Holle


From news.service.uci.edu!usc!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu!parsifal.umkc.edu!parsifal.umkc.edu!gcombs Fri Oct  9 22:48:00 PDT 1992
Article: 33618 of comp.sys.mac.hardware
Path: news.service.uci.edu!usc!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu!parsifal.umkc.edu!parsifal.umkc.edu!gcombs
Newsgroups: comp.sys.mac.hardware
Subject: Re: HOW TO UPGRADE YOUR IIsi TO 25MHz
Message-ID: <[e-mail]>
From: [e-mail] (Gerald Combs)
Date: Thu, 8 Oct 1992 17:46:09 GMT
Reply-To: [e-mail] (Gerald Combs)
Sender: [e-mail] (Parsifal Administration)
References: <[e-mail]> <[e-mail]>
Distribution: usa
Organization: University of Missouri - Kansas City
Lines: 35

In article <[e-mail]>, [e-mail] (Steve Strange) writes:
>In article <[e-mail]> [e-mail] (George John) writes:
>
>   Desolder the 40MHz oscillator.  You should see a row of little silver
>   boxes just to the right of the simm slots.  The one closest to the
>   simms should say 40.000 MHz on it.  This is the guy to desolder.
>   You could really screw things up here, so be careful with the soldering
>   iron.  I removed mine by working on a pair of pins at a time -- get one
>   pin hot enough to melt the solder, then quickly switch to the adjacent
>   pin and heat that pin while prying the oscillator away from the motherboard
>   on the other side.  Switch back and forth between the pair while prying
>   until one side has been completely detached from the motherboard, then
>   work on the other side.
>
>Thanks for the info!  I just might try this.  One thing about this
>part tho':
>
>I would strongly recommend using solder wick for the removal of the
>crystal.  This will be a lot faster and probably safer (won't have to
>heat up the board etch nearly as much).  Also, then there won't be any
>solder already on the board when you go to put in the socket, so that
>procedure will turn into a 30-second affair rather than a number of
>minutes.  And again, this will be more gentle on your board.

  You might also want to use a desoldering iron, < $20 at Radio Shack.  The ones
Rad Shack sells are basically a regular soldering iron with a hollow tip and an
attachment with a rubber bulb.  Just squeeze the bulb, touch the tip to the
joint, release the bulb, and all the solder is sucked up into the iron.  You can
remove every component from a motherboard in a matter of minutes with one of
these things.

- Gerald Combs
     _____     __o          Internet : [e-mail]
   -----      -\<,            Bitnet : gcombs@umkcvax1
    -----   ( )/ ( )


From news.service.uci.edu!usc!elroy.jpl.nasa.gov!ames!decwrl!adobe!dtomack Fri Oct  9 23:37:09 PDT 1992
Article: 33630 of comp.sys.mac.hardware
Newsgroups: comp.sys.mac.hardware
Path: news.service.uci.edu!usc!elroy.jpl.nasa.gov!ames!decwrl!adobe!dtomack
From: [e-mail] (Darin Tomack)
Subject: Re: HOW TO UPGRADE YOUR IIsi TO 25MHz
Message-ID: <[e-mail]>
Sender: [e-mail] (USENET NEWS)
Organization: Adobe Systems Incorporated, Mountain View
References: <[e-mail]> <[e-mail]>
Distribution: usa
Date: Thu, 8 Oct 1992 22:13:48 GMT
Lines: 22

In article <[e-mail]> [e-mail] (Jess M Holle) writes:
>I know a couple of people who have done similar things with other
>machines, with no problems to the best of my knowledge.
>
>One sped a IIfx up to 50MHz, the other sped a Quadra 900 up to 33MHz
>(ala 950).  They DID add heat sinks and more powerful fans.
>
>Jess Holle

Does anyone know of anyone who has done something similar to a IIci?  Does
anyone know if it is possible to do this successfully to a IIci?  My main
concern would be if the cache card would still function correctly (or even be
useful?)  Also, how bad would it screw up the video timing, or would it?


Thanks,

    darin
--
Darin Tomack                                             [e-mail]
                                                  ...!{sun,decwrl}!adobe!dtomack



From news.service.uci.edu!usc!cs.utexas.edu!tamsun.tamu.edu!sigma.tamu.edu!j0m1247 Sat Oct 10 00:15:44 PDT 1992
Article: 33608 of comp.sys.mac.hardware
Newsgroups: comp.sys.mac.hardware
Path: news.service.uci.edu!usc!cs.utexas.edu!tamsun.tamu.edu!sigma.tamu.edu!j0m1247
From: [e-mail] (MARCOS, JULIO)
Subject: SI to 25 MHz: What about coprocessor?
Message-ID: <[e-mail]>
News-Software: VAX/VMS VNEWS 1.41
Sender: [e-mail] (Read News)
Organization: Texas A&M University, Academic Computing Services
Date: Thu, 8 Oct 1992 17:03:00 GMT
Lines: 15

Before performing the upgrade, I 'd like to know if it is going to be OK
with my FPU: are they  both going to run at 25Mhz?
There is no crystal for the FPU, so I guess I am not going to
have a 5Mhz difference.

What about consumption power? My FPU is located in the Radius Color Pivot
card. Any comments?



Julio Marcos
Texas A&M University
College Station, Texas
                "Still pristine... Looking grreat!"
[e-mail]


From news.service.uci.edu!usc!cs.utexas.edu!tamsun.tamu.edu!sigma.tamu.edu!j0m1247 Sat Oct 10 00:17:12 PDT 1992
Article: 33641 of comp.sys.mac.hardware
Newsgroups: comp.sys.mac.hardware
Path: news.service.uci.edu!usc!cs.utexas.edu!tamsun.tamu.edu!sigma.tamu.edu!j0m1247
From: [e-mail] (MARCOS, JULIO)
Subject: SI to 25 Mhz: What about the FPU?
Message-ID: <[e-mail]>
News-Software: VAX/VMS VNEWS 1.41
Sender: [e-mail] (Read News)
Organization: Texas A&M University, Academic Computing Services
Date: Fri, 9 Oct 1992 01:24:00 GMT
Lines: 21

Ok, now we know how to make our PCU go to 25 Mhz. But then, some guys such
as me have a coprocessor.
Does that mean that we will have a 5Mhz lag between the CPU and the FPU?
-> I don't think so, because the coprocessor does not have its own quartz
crystal.

What about power consumption? My CPU is located in the Radius Pivot Color LE
card, but most of the people will have it on PDS expansion cards, as I used
to. Any comments, suggestions?

Most important question: HAS ANYONE (HAVING THE COPROCESSOR) DONE THE UPGRADE?

Thanks.



Julio Marcos
Texas A&M University
College Station, Texas
                "Still pristine... Looking grreat!"
[e-mail]