Replacing a 68030 in a IIci?

[tattar8]

I have a IIci board which apparently had a dead 68030, which was removed leaving a clean pad.  I'm trying to figure out what I can use to replace it.

I know the IIci ran at 25 MHz, but for some reason 25 MHz 68030s are expensive on eBay.  However, 33 MHz chips seem to be far more plentiful.  Will a 33 MHz chip run fine at 25 MHz in the IIci?

This is the part I'm thinking of using:  https://www.ebay.com/itm/1pcs-MC68030FE33C-ENHANCED-32-BIT-MICROPROCESSOR/392523139565

 

[johnklos]

33 MHz parts will run perfectly fine at 25 MHz. They're identical except the 33 MHz part was tested at a higher speed.

I do hope that's a real part. While I got an m68882 which was, according to the markings on the package, made in 2012, sometimes newer parts from China are fakes.

 

[Bolle]

I did exactly that on one of my IIci boards. Works just fine at 25MHz with a33MHz chip in place.

Those chips you linked are probably fake anyways, I ordered a few of them not long ago and the silkscreen on most of them is sketchy (+they all arrived with horribly bend legs)

They do work just fine though, once you went through the trouble of straightening the legs and soldering it down.

 

[trag]

If they're fake and they work fine once installed, what does that mean?   They're not really 33MHz parts?   Surely someone isn't fabricating pirate 68030 CPUs?  

 

[Bolle]

Not going to speculate over "why" reworking those chips is a thing...

But see for yourself:

This is exactly how I got it from the seller linked above.

The markings on the chips do seem to be what was on there originally. On some it could be washed off with acetone, on some it stayed on. On one chip you can see signs of either a round heatsink or leftovers from grinding off the old markings.

 

[Byrd]

I'm assuming if a seller has hundreds/thousands of 030 and 040 CPUs and you can double or triple your money with fake badges it's worth the effort

 

[Bolle]

But at $4 a pop for those QFP chips? Also the bad packaging job earned them nothing, because I got a full refund for those.

I really don't see through their business model.