Macintosh IIfx 68030/50Mhz？？？

[nekogahora280]

I replaced the crystal oscillator in my Macintosh IIfx from 80MHz to 100MHz, but there was no startup chime, and thinking I had broken it, I hurriedly reverted to the original, which then worked normally. Does simply swapping the crystal oscillator not work?

After removing the crystal oscillator, I installed a socket to allow the crystal oscillator to be freely replaced.
I was under the impression that it would operate at 68030/50MHz with this.
Is there anyone with experience?

 

[Kai Robinson]

That much of a jump is simply too much for the entire system, when you swap that oscillator, you're also overclocking the system bus and everything attached to it.

 

[nekogahora280]

That much of a jump is simply too much for the entire system, when you swap that oscillator, you're also overclocking the system bus and everything attached to it.

I simply thought that since the crystal oscillator was 80 MHz, replacing it with a 100 MHz one would make it operate at 50 MHz. How was Dash 030 managing to operate at 50 MHz? I'm curious.

 

[ESM-NL]

I simply thought that since the crystal oscillator was 80 MHz, replacing it with a 100 MHz one would make it operate at 50 MHz. How was Dash 030 managing to operate at 50 MHz? I'm curious.

In the IIfx, all the systems and parts working together in a highly efficient way. Changing 1 or 2 things can simply cause that it wont work anymore.

 

[nekogahora280]

In the IIfx, all the systems and parts working together in a highly efficient way. Changing 1 or 2 things can simply cause that it wont work anymore.

I have a board like this, but I got the cables to connect it with lost, so I can't use it for now.
I've heard that IIfx can run at 50Mhz with this, but is there a site somewhere that has information?

 

[jmacz]

I remember seeing notes of varying degrees of success online, some folks having replaced the cpu and fpu with higher rated versions to achieve it. As usual with over clocking, depends on the components on your particular logic board (not just cpu) and whether they will be stable at higher clock speeds but there definitely were some success stories, even at 55-57MHz with replaced cpus/fpus. But just because some got it working, doesn’t mean it will work on yours. It will be a hit and miss.

I never tried on my IIfx. My Quadra 800 needed a newer mask CPU. One of two CPU cards on my PowerBook 540c didn’t want to work (ended up replacing the CPU on the one that didn’t work). My Quadra 700 is using a quad doubler as the system components didn’t want to go faster. One other member had problems with his memory controller on his PB540c at higher clock speeds. So point is its going to be a hit and miss on every specific logic board and one persons success doesn’t mean it works for all.

 

[nekogahora280]

I remember seeing notes of varying degrees of success online, some folks having replaced the cpu and fpu with higher rated versions to achieve it. As usual with over clocking, depends on the components on your particular logic board (not just cpu) and whether they will be stable at higher clock speeds but there definitely were some success stories, even at 55-57MHz with replaced cpus/fpus. But just because some got it working, doesn’t mean it will work on yours. It will be a hit and miss.

I never tried on my IIfx. My Quadra 800 needed a newer mask CPU. One of two CPU cards on my PowerBook 540c didn’t want to work (ended up replacing the CPU on the one that didn’t work). My Quadra 700 is using a quad doubler as the system components didn’t want to go faster. One other member had problems with his memory controller on his PB540c at higher clock speeds. So point is its going to be a hit and miss on every specific logic board and one persons success doesn’t mean it works for all.

Is simply replacing an 80MHz crystal oscillator with a 100MHz one the correct method for overclocking? Or is it just that my machine wasn’t compatible?