Identifying and confirming fake 68040 CPUs (especially the L88M mask)

Kai Robinson

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I bought the 68040 below from Eric Woo last summer for my Mystic CC. I’ve overclocked it to 40 MHz with no issues I’ve seen so far, with plans to push it even further in a few weeks.

View attachment 5035

Eric Woo is the rose amongst the thorns - all legit pulls, never remarked!
 

Mr. Fahrenheit

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Sep 2, 2021
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For reference:​

Mask revisions of the 68040 variant​

Note: The table only applies to the full 68040, there are other masks for the EC and LC variants!
maskYearproductionXC/MC
D43B19890.8µmxc
D50D19890.8µmxc
D98D19890.8µmxc
E31F19890.8µmxc
E26A1992-19950.65µmxc
E42K19950.65µmMC
K63H20000.57µmMC
L88M20020.57µmMC
packageSocketmaskYearstructure sizeXC/MC
Quad Flat PackageQFP1840.5µmMC68040FE25V
Quad Flat PackageQFP1840.5µmMC68040FE33V
Quad Flat PackageQFP1840.5µmMC68040FE40V
Pin Grid ArrayPGA17902E42K19950.65µmMC68040RC33, MC68040RC25
Pin Grid ArrayPGA17903F54F0.5µmMC68040RC25V
Pin Grid ArrayPGA179?0.5µmMC68040RC33V
Pin Grid ArrayPGA179?0.65µmMC68040RC40
Pin Grid ArrayPGA179?0.5µmMC68040RC40V
Pin Grid ArrayPGA17920D43B19890.8µmXC68040RC25
Pin Grid ArrayPGA17926D43BXC68040RC25
Pin Grid ArrayPGA17904D50D19890.8µmXC68040RC25A
Pin Grid ArrayPGA17909D50DXC68040RC25B
Pin Grid ArrayPGA17902E31F19890.8µmXC68040RC25M
Pin Grid ArrayPGA179XC68040RC33
Pin Grid ArrayPGA17905D98D19890.8µmXC68040RC33E
Pin Grid ArrayPGA17905O98DXC68040RC33E
Pin Grid ArrayPGA17907D98D19890.8µmXC68040RC33E
Pin Grid ArrayPGA17900E31F19890.8µmXC68040RC33M
Pin Grid ArrayPGA17902E31F19890.8µmXC68040RC33M
Pin Grid ArrayPGA179XC68040RC40
Pin Grid ArrayPGA17902E31F19890.8µmXC68040RC40M
 

bakkus

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Fantastic!
Could this table be placed as an article under Resources as well?
 

JDW

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I’m still curating this information. It’s not complete yet.
If you like, you can do a copy/paste of your excellent table content as an Article (if some folks would find that more helpful), because unlike a certain other forum which shall not be named, you can Edit posts here on TinkerDifferent. 🥳 "Articles" in the "Resources" section are especially made for edits and updates, and here's one example of an Article which has been updated by its author. Anyone should be able to do those edits/updates without any special mod or admin privileges.

At some point, nobody will be able to acquire fast 40MHz rated 040 CPUs anymore, and we will need a modern replacement to enjoy overclocking. I've long read about the PiStorm project which replaces a 68000 CPU, but even to this day, it doesn't work in a Mac. But just imagine a full 68040 with FPU modern equivalent that could be overlocked to 50MHz and higher without any heatsink or fan. One can dream, right? 🤓
 

Gazmassive

New Tinkerer
May 16, 2022
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So the last Eric Woo chip has just arrived. I've attached photos of the altered chip and the new one. Also are both underneath shots.
The markings on the new chip are almost impossible to see, but its just only cleaned and not re-masked. I'm also not sure of what the H in the XC68040HRC40M is in reference to.

If anybody has a some more tests besides MacBench to run, please let me know.
Have a good one!

PS (excuse the dirty hands, being a diesel mechanic has its downsides)
PXL_20220527_104632707.jpg


PXL_20220527_104646782.jpg
PXL_20220527_104949606.jpg
PXL_20220527_104931410.jpg
 
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Mr. Fahrenheit

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So the last Eric Woo chip has just arrived. I've attached photos of the altered chip and the new one. Also are both underneath shots.
The markings on the new chip are almost impossible to see, but its just only cleaned and not re-masked. I'm also not sure of what the H in the XC68040HRC40M is in reference to.

If anybody has a some more tests besides MacBench to run, please let me know.
Have a good one!

PS (excuse the dirty hands, being a diesel mechanic has its downsides)
View attachment 5293

View attachment 5294View attachment 5295View attachment 5296
HRC is supposed to indicate that the chip was binned for producing less heat.

I do not know how accurate that is.
 
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C128 Guy

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Aug 9, 2022
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I've recently purchased a number of 040's and 060's from Ebay seller Eric Woo's Rare Chips. Had quite a few conversations with him as well about fake chips. He's been vey honest with me and everything is as promised. 6 chips total from there (2 x rev6 060).

Eric tells me there are ZERO legit L88M's @ 40mhz remaining anywhere in China unless more equipment with them gets scrapped. He confirmed any of the 40mhz chips listed currently are fake.

MTXStore refunded 100% of my money instantly, they know what they are doing. It was my first 040 purchase I thought I would gamble on. Looked fake in the pics, was certainly fake when it arrived. I suspect it is a E31F, and will have it x-rayed soon to report back. Won't know what mhz it was rated for but at least can check the package.
 
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Kai Robinson

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I've recently purchased a number of 040's and 060's from Ebay seller Eric Woo's Rare Chips. Had quite a few conversations with him as well about fake chips. He's been vey honest with me and everything is as promised. 6 chips total from there (2 x rev6 060).

Eric tells me there are ZERO legit L88M's @ 40mhz remaining anywhere in China unless more equipment with them gets scrapped. He confirmed any of the 40mhz chips listed currently are fake.

MTXStore refunded 100% of my money instantly, they know what they are doing. It was my first 040 purchase I thought I would gamble on. Looked fake in the pics, was certainly fake when it arrived. I suspect it is a E31F, and will have it x-rayed soon to report back. Won't know what mhz it was rated for but at least can check the package.

L88M's might be the pinnacle, but the K63H's are good - maybe he has some of them? Also E42K RC33's would be a decent buy.
 

C128 Guy

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Aug 9, 2022
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Think these are real?

 

retr01

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Mr. Fahrenheit

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Who wants to gamble $100? :)

If it were $50, I would. $100 is a bit much for this in my opinion. Especially for an unknown.

I think there’s a danger that some of these remarking fraudsters could be reading up on what mistakes they’re making with regards to the fakes, and remarking them to remove the errors they’ve had in the past.

Although the danger of that on a 33mhz chip is likely lower than the unicorn 40mhz chips.

The -101 matches the E42K and the date code of 1999 coincides with that mask and the style of print.

I would say it’s a toss up whether it’s legitimate or not. However, who would have trays of pristine 68040 chips ready to sell from China? All identical…. 🤔
 
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C128 Guy

New Tinkerer
Aug 9, 2022
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Eric Woo confirms no 33mhz chips left either. He's response was even 25mhz are getting rare now and he hasn't bought any in over a month. We are nearing the end guys....
 

Mr. Fahrenheit

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Eric Woo confirms no 33mhz chips left either. He's response was even 25mhz are getting rare now and he hasn't bought any in over a month. We are nearing the end guys....

I wonder how many were bought up by Mac users, and how many were for Amigas.

The 40mhz variant will likely be the rarest of all of the 68040 chips.

 
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