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?

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.

>> Kai Robinson said:

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. Click to expand...

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.

>> nekogahora280 said:

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. Click to expand...

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.

>> ESM-NL said:

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. Click to expand...

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?

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.

>> jmacz said:

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. Click to expand...

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?

>> nekogahora280 said:

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? Click to expand...

Basically yes, but hoping someone responds here that has done it and been successful or failed, and might have additional tips.

I remember seeing this a few years back but decided to keep mine stock so never tried.

My IIfx is running at 50 MHz without any problems -- I use it almost every day. I added heatsinks all over the board and a tiny laptop fan on the CPU, but it doesn't get very hot compared to stock.

>> Hugotronics said:

My IIfx is running at 50 MHz without any problems -- I use it almost every day. I added heatsinks all over the board and a tiny laptop fan on the CPU, but it doesn't get very hot compared to stock. Click to expand...

Is the method of clocking up just a modification of an 80Mhz crystal oscillator replaced with a 100Mhz crystal oscillator? All that's left is to cool the MC68030 with a small fan? Please tell me what you think.

>> nekogahora280 said:

Is the method of clocking up just a modification of an 80Mhz crystal oscillator replaced with a 100Mhz crystal oscillator? All that's left is to cool the MC68030 with a small fan? Please tell me what you think. Click to expand...

Yes, simply replacing the crystal is enough. Even without a heatsink or fan, it should work fine. Is your crystal working properly? I got mine from Aliexpress.

>> Hugotronics said:

Yes, simply replacing the crystal is enough. Even without a heatsink or fan, it should work fine. Is your crystal working properly? I got mine from Aliexpress. Click to expand...

As shown in the first image of the thread, I put a socket on it so that the crystal oscillator could be replaced, and installed a used 100Mhz crystal oscillator.
There's no startup sound. When I replaced it with an 80Mhz crystal oscillator, it started to start normally with the startup sound. It is unknown whether the crystal oscillator was the cause.
However, yesterday IIfx was given the next owner today, so I can't confirm it.

Did you make sure the crystal was oriented correctly? It worked fine for me twice.

>> Hugotronics said:

Did you make sure the crystal was oriented correctly? It worked fine for me twice. Click to expand...

I remember that I removed the crystal a few times but
It didn't start. That's the only way to get the original crystal
It was plugged in and operated at 40Mhz.
Today, IIfx has set out to become the next owner.
Once you get the next one, replace it with a socket again.
I'd like to try speeding up.