Upgrading Powerbook 190 to 68040 with FPU?

DominBear

New Tinkerer
Jul 18, 2025
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Can it be done?
I tried installing MC68040FE33V but no chime. CPU gets warm so it does something? Soldered LC back, works again.
Does the ROM care about it? They are pin compatible and the only difference should be FPU?
 

Fizzbinn

Tinkerer
Nov 29, 2021
229
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43
Charlottesville, VA
I recall reading somewhere about someone else doing this successfully, ...and something about only specific CPU part numbers working in Macs. Was it a 5V vs 3.3V thing?



I think these are saying you need one of these:

MC68040FE25A
MC68040FE33A
MC68040FE40A



and that the ends in V version actually doesn't have an FPU and is 3.3V not 5V.
 

jmacz

Tinkerer
Mar 21, 2025
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I have successfully done it on a PowerBook 540c and a PowerBook Duo 280c. @croissantking is the first I saw do it successfully (the above link is to his thread) on his 540c which is what inspired me.

Never tried on a 190.
 

DominBear

New Tinkerer
Jul 18, 2025
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I tried these CPUs https://www.ebay.com/itm/226944137012

68040.jpg
 

DominBear

New Tinkerer
Jul 18, 2025
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3
Ah crap. It looks like V is 3.3V part. So I probably fried it a bit ;-)
I guess I need to find 5V part and try again.