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

JDW

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I purchased two x 68040 40mhz CPUs, supposedly L88M from this eBay seller:


They are not legitimate. They are remarked fakes. See attached photos.
Just goes to show that observing a seller's feedback alone is insufficient to determine if what you buy is the real deal...

1652489646815.png


When viewing your photos, @Mr. Fahrenheit, what specifically must web observe which proves they are fake? (I ask out of ignorance here... not trying to be argumentative.)

Also, what happened with those CPUs in your testing? The reason I am curious about that is because, as you know, I purchased a 40MHz rated 040 from UT Source and found the markings came off after @Kay K.M.Mods applied a heatsink with 2-sided thermal tape and then later removed it. The authentic chip markings won't come off like that, proving it was remarked. However, despite that serious warning sign, I was able to overclock it with Spicy O'Clock to 49.2MHz using your 60ns VRAM (and also that of Drake), and later I was able to overclock 1MHz higher with the 2-chip low-latency SMC VRAM. In other words, despite the remarking (which means I have no idea if it was originally a 40MHz rated or 33MHz rated chip), I can overclock it to amazing speeds, and the temperatures never rose above the 60's°C.

So in my mind, I view the remarked chips in two categories: (1) remarked chips that are known to be low-megahertz and cannot be overclocked very high and/or get very hot, and (2) remarked chips that can be overclocked and don't get very hot. Maybe even the sellers don't know which category they fall into, assuming the sellers weren't the one's who remarked them. Maybe they bought a bunch of old chips from another vendor on the cheap and then just resold them?

All said, it would seem that the only way to know what your getting is to get an authentic chip, and then main way to guarantee that is to pull it from an old Quadra or another 040 Mac or Amiga. But few people would probably do that, as such would render that machine unusable. Then again, I am willing to sacrifice a Quadra 630 to donate parts (like a speaker for the stereo mod) into a Color Classic because the Color Classic is the better machine overall. I did just that a few months back in fact (just haven't made the video yet).
 

JDW

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Always an idea to look for a K63H - just as good as the L88M - you tend to find most of those at least are pulls, not NoS :)
But where would you be able to reliably and consistently purchase those authentic K63H mask versions online, Kai?
 

Mr. Fahrenheit

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Just goes to show that observing a seller's feedback alone is insufficient to determine if what you buy is the real deal...

View attachment 4973

When viewing your photos, @Mr. Fahrenheit, what specifically must web observe which proves they are fake? (I ask out of ignorance here... not trying to be argumentative.)

Also, what happened with those CPUs in your testing? The reason I am curious about that is because, as you know, I purchased a 40MHz rated 040 from UT Source and found the markings came off after @Kay K.M.Mods applied a heatsink with 2-sided thermal tape and then later removed it. The authentic chip markings won't come off like that, proving it was remarked. However, despite that serious warning sign, I was able to overclock it with Spicy O'Clock to 49.2MHz using your 60ns VRAM (and also that of Drake), and later I was able to overclock 1MHz higher with the 2-chip low-latency SMC VRAM. In other words, despite the remarking (which means I have no idea if it was originally a 40MHz rated or 33MHz rated chip), I can overclock it to amazing speeds, and the temperatures never rose above the 60's°C.

So in my mind, I view the remarked chips in two categories: (1) remarked chips that are known to be low-megahertz and cannot be overclocked very high and/or get very hot, and (2) remarked chips that can be overclocked and don't get very hot. Maybe even the sellers don't know which category they fall into, assuming the sellers weren't the one's who remarked them. Maybe they bought a bunch of old chips from another vendor on the cheap and then just resold them?

All said, it would seem that the only way to know what your getting is to get an authentic chip, and then main way to guarantee that is to pull it from an old Quadra or another 040 Mac or Amiga. But few people would probably do that, as such would render that machine unusable. Then again, I am willing to sacrifice a Quadra 630 to donate parts (like a speaker for the stereo mod) into a Color Classic because the Color Classic is the better machine overall. I did just that a few months back in fact (just haven't made the video yet).

The date code in the corner does not correspond to the Motorola logo, and the mixed corner logo (one being a circle, the other being a triangle), along with the surface appearing to be buffed/sanded down, and the serial numbers on the left side end -001 which indicates it’s not L88M.

All of these things, and I haven’t powered it up yet to know whether they are even full 040 (instead of LC040).

I’ll do that test and temperature readings sometime this weekend, hopefully.
 
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JDW

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At least determining whether they have an FPU or not is reasonably simple.
More specifically, adding the CPU to your computer, then switching on power and launching an app like Norton System Info (or another benchmark utility) which will tell you if the FPU is present or not.
 

yock1960

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It may be an acceptable risk, at least with this particular seller, as they appear to be willing to go to great lengths to avoid negative feedback, if one is looking for a full 68040 and also willing to put up with some aggravation. After a couple of months, my 'fake' is performing as well as I could want, at >40mhz.

I've read up a bit on this topic and it could be that these sellers or some of them anyway, could be getting more sophisticated, so as to perform rudimentary testing to ensure that these CPUs can perform at 40mhz, at least so far as to boot a system. If so, you might go so far as to say that they are providing a 'service' to the 'retro' community. 🤔🥴😄

As is said however, forewarned is forearmed...do your homework!
 

Mr. Fahrenheit

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Have you found a need for heatsink at 33MHz with those steppings?
I’m still working on getting Flir temperature images of each CPU die running at 33mhz combined with what the CPU is masked as rated to run at, along with the specific masking so that a correlation can be made between masks and expected temperature ranges.

To ensure integrity I’m hoping to test at least two of each that I post, so that the results can be averaged between two or more to provide a guideline.

However, the temperature of K63H on my 33mhz was nearly half the temperature of an older masking on the same machine at the same speed.

I also want to take temperature readings with an aluminium heat sink applied to compare.

More to come when I get time.
 

Mr. Fahrenheit

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@JDW
I took one for the team, and posted a negative review of the seller to warn others. It means I won’t be able to get a refund. Once a seller gives a refund they can get negative feedback left AFTER the refund removed. I left feedback first so even if they refund me I think it stays. But the motivation for the seller to refund me is removed now, so that is unlikely.
 

Gazmassive

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Hi guys, first time long time on the forums and other accounts.

After watching JDW's video on Spicy O'Clock, i decided to go ahead and order a full fat 68040 off UTSource.

After waiting about a month for shipping to Australia, it finally arrived. From all the previous comments, this seems to be another rebranded one.
It has a K88M mask (never seen this before), but in the lower corner is marked as a -010-F, suggesting a very early chip.

Is there a way to test the processor using a tool suite to see if indeed full functionality is present even though its rebranded?
PXL_20220515_102705690.jpg

MacBench 3 sees it as a full 040 with FPU and tests ok.

PXL_20220515_053114391.jpg
 
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JDW

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Is there a way to test the processor using a tool suite to see if indeed full functionality is present even though its rebranded?
MacBench 3 sees it as a full 040 with FPU and tests ok.
That kind of testing is the best you can do to determine if it has the full FPU. The next step is to see how high you can overclock it using the fastest VRAM possible and board recapped with the best capacitors. Then you just need to measure the temperature of the CPU while running an intensive benchmark.
 

JDW

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For anyone looking for a legitimate chip seller and wanting a 68040 40mhz chip, I can recommend Eric Woo:


I have bought several from Eric Woo, and all were legitimate chips. eBay listing shows only 1 left!
Going under the assumption that all of Eric Woo's chips really are authentic pulls and not rebadged, I have a couple questions (which we may or may not have discussed privately by email in the past)...

1. Have you tried using thermal tape and a heatsink (applying it and then removing it) to see if the chip markings are still there? (That would be strong evidence of an authentic chip)

2. Did you experience shipping times of 2.5 months? (Checking just now says that if I were to buy it and have it shipped to Japan -- a next door neighbor to China, mind you -- it may not arrive until August 1st!)

3. Did you experience any bent or broken pins or an otherwise seriously beat up chip?

4. Have you overclocked any beyond 40MHz to see how stable they are at high overclocks and check their temperature?

Thanks for the useful info, @Mr. Fahrenheit !
 

Gazmassive

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@JDW, I purchased the last chip off EricWoo today as a back up. It reports as July for delivery to Australia (even though their SpeedPAK service to here is pretty quick).

I'm looking to get the fast VRAM as soon as Kay Koba has it for sale, as it's still not listed. But would still need to send the board to Bruce for a recap as I don't possess the full set of skills for replacing the caps (harder than through hole ones in aFamicom).

Instead of thermal tape to remove the false chip markings, could something slightly abrasive like a Scotch Brite pad be used instead? Or a light polishing compound to remove the top layer?

Will report back later with thermals on the false marked chip.

@Mr. Fahrenheit what chip markings did you get from Eric Woo? Late or early or a mix of all?
 
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Mr. Fahrenheit

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@JDW, I purchased the last chip off EricWoo today as a back up. It reports as July for delivery to Australia (even though their SpeedPAK service to here is pretty quick).

I'm looking to get the fast VRAM as soon as Kay Koba has it for sale, as it's still not listed. But would still need to send the board to Bruce for a recap as I don't possess the full set of skills for replacing the caps (harder than through hole ones in aFamicom).

Instead of thermal tape to remove the false chip markings, could something slightly abrasive like a Scotch Brite pad be used instead? Or a light polishing compound to remove the top layer?

Will report back later with thermals on the false marked chip.

@Mr. Fahrenheit what chip markings did you get from Eric Woo? Late or early or a mix of all?

I purchased several chips from Eric Woo. One of which I shipped to @JDW (which he re-shipped to Kay Koba).

Some were K63H and some were E31 and some were E42. All were in good condition, and obvious they were just system pulls. They looked a little used and not pristine, which I think is a dead give away on a remarked chip.

None of them had bent pins. Some from other sellers which I received and were remarked had bent pins.

Can you please post a photo of the bottom of your CPUs? There seems to be a way of at least determining whether it’s a very early CPU or one which is later. The gold cap on the bottom went almost right to the edge of the inner pins on early 040s, and shrink as they did die shrink revisions.

Not sure if you are aware, but I also make 60ns VRAM.
 
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Mr. Fahrenheit

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Going under the assumption that all of Eric Woo's chips really are authentic pulls and not rebadged, I have a couple questions (which we may or may not have discussed privately by email in the past)...

1. Have you tried using thermal tape and a heatsink (applying it and then removing it) to see if the chip markings are still there? (That would be strong evidence of an authentic chip)

2. Did you experience shipping times of 2.5 months? (Checking just now says that if I were to buy it and have it shipped to Japan -- a next door neighbor to China, mind you -- it may not arrive until August 1st!)

3. Did you experience any bent or broken pins or an otherwise seriously beat up chip?

4. Have you overclocked any beyond 40MHz to see how stable they are at high overclocks and check their temperature?

Thanks for the useful info, @Mr. Fahrenheit !
The 68040 40mhz chip I sent to you was from Eric Woo.
 
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Mr. Fahrenheit

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For anyone looking for a legitimate chip seller and wanting a 68040 40mhz chip, I can recommend Eric Woo:


I have bought several from Eric Woo, and all were legitimate chips. eBay listing shows only 1 left!

Looks like this link is dead because the CPU has now been sold. So it’s a moot point.

Another option for overclockers could be to find a good XC68040HRC33M, as these apparently were binned by Motorola during production to operate at a lower heat output than standard production chips. It is possible to run one without a heat sink at 33mhz. I have not validated these claims or tested any, but it would be a good project to determine if it is correct.

Seems like a specific chip that would be unlikely to be remarked and so a listing of that specific masking should be legitimate. As @Kai Robinson mentioned earlier in the thread, looking for K63H should also result in a legitimate chip. It seems the fakers target 40mhz L88M masks.

If anyone wants to try out a “HRC” chip with a spicy o’clock and has access to a FLIR, one can be found here:


I have not bought from this seller so I cannot endorse or promote them as being legitimate. Only providing the link here for convenience. I did message the seller to confirm that it is exactly as described and pictured and they replied back that it is.
 
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