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Clock chip and speedup the Macintosh IIsi to 25 MHz?

 
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MacOS
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PostPosted: Fri Nov 28, 2008 5:12 pm    Post subject: Clock chip and speedup the Macintosh IIsi to 25 MHz? Reply with quote

I searched for an hour and did not find anything about the Trick to "clock chip" my Macintosh IIsi so it has the full 25 MHz (or even 40 MHz?) performance that is inside the board.

Question Does anyone knows more about speeding the Mac IIsi ?

this says http://lowendmac.com/ii/macintosh-iisi.html

Quote:
The IIsi was designed as a less expensive, less expandable alternative to the Mac IIci. Cost saving measures included eliminating NuBus expansion slots, soldering 1 MB of RAM to the motherboard, and using a slower CPU (20 MHz vs. 25 MHz). Although the IIsi was marketed as a 20 MHz computer, users quickly discovered it used parts rated at 25 MHz. (Apple had intended it as a 25 MHz computer, but chose to scale back the speed to avoid cutting into IIci sales.) Chipping the IIsi to 25 MHz -- or even 28 MHz - is not unusual.


at http://en.wikipedia.org/wiki/Macintosh_IIsi

Quote:
Because of its heritage as a cut-down IIci, a simple modification carried out by many owners was to substitute a new clock crystal to increase the speed to 25 MHz.


Seems I need to get a faster clock crystal.
Question Hum... where can I get that one... ?

At www.apple-history.com I found

Quote:
The IIsi came in a streamlined case used only for this model. It was originally designed for a 25 MHz 68030 processor, but shipped at 20 MHz, so it wouldn't compete with the IIci.


Question Do you think I can add a 25 MHz 68030 processor to speed it up ?
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applefreak



Joined: 11 Oct 2006
Posts: 59
Location: belgium

PostPosted: Sun Nov 30, 2008 4:14 pm    Post subject: Reply with quote

The hack required soldering on the logic board so was not for the faint of heart.
(Detailed instructions for the hack were available from the Berkeley Macintosh User Group.)

http://mac.wikia.com/wiki/Macintosh_IIsi

perhaps you can get additional info at :
http://www.planetmug.org/index.html

About PlanetMUG
BMUG, the Berkeley Macintosh Users Group, was formed in 1986 in the spirit of the Homebrew Club but dedicated to the Mac.

In 2000, PlanetMUG, a new organization formed by former BMUG members

PS all my IIsi macs (6) are 20 MHz
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PostPosted: Sun Nov 30, 2008 11:33 pm    Post subject: Reply with quote

hm.. 25 MHz seem not so desireble if you need to solder on the MoBo.
I leave it on 20 MHz and be happy with it.
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