Question about MC68882FN40A on Ebay

amiman99 · 25 March 2020, 03:34

Few years back I purchased new Freescale FPU MC68882FN40A on Ebay from China.
I could never get it to work beyond 25MHz.
I just found out that Laser etched labels are possibly fakes, and mine is Laser etched.
I got a feeling that most MC68882FN40A chips on Ebay are fakes, so how do I spot a real one? Do real ones exist in 40MHz?

Any tips?

Thanks

dalek · 25 March 2020, 05:00

All I do is buy multiples of the cheapest FPUs. Generally 1 in 4 will do 50MHz but your mileage may vary.

Pretty much all the ones from China/HK on eBay / Aliexpress come from the same source or rebadged/relabelled/seconds stock.

axel81l · 25 March 2020, 11:55

I don't understand why you keep buying components from China ... especially vintage ICs

They are able (personally verified) to sell you banal brushed and rebranded OTP 27C512.

If you buy from China you need to know the market and know serious suppliers and not scammers

Thomas Richter · 25 March 2020, 13:03

Quote:

Originally Posted by amiman99

I got a feeling that most MC68882FN40A chips on Ebay are fakes, so how do I spot a real one? Do real ones exist in 40MHz?

Real ones do exist, I have one. But this was bought in better times. Came on a 40Mhz GVP 030 GForce.

amiman99 · 25 March 2020, 17:20

Can I overclock real 33MHz to 50MHz safely? Looks like real 33MHz are easier to find.

amiman99 · 25 March 2020, 17:22

Quote:

Originally Posted by axel81l

I don't understand why you keep buying components from China ... especially vintage ICs

They are able (personally verified) to sell you banal brushed and rebranded OTP 27C512.

If you buy from China you need to know the market and know serious suppliers and not scammers

I got mine long time ago, and I did not know then that there are fakes around. Who knew that they will fake cheap vintage ICs?

axel81l · 25 March 2020, 17:54

These IC goes out of production.
You have three possibilities:

1)Take used and do what the Chinese do by putting the pins in a tin.
2) Find real IC used
3) Find real Brand new

For a lot of Commodore ICs there are not a substitute ... and those that exist never 100% replicate the functionality of the original.

Unfortunately, more and more of these ICs products will disappear .. and for all rarities, prices go up .. it is a law of the universal market.

FOL · 25 March 2020, 18:07

If your after PLCC version. Which work fine at 40MHz.

https://amigakit.amiga.store/product...6&currency=GBP

amiman99 · 25 March 2020, 20:11

Quote:

Originally Posted by FOL

If your after PLCC version. Which work fine at 40MHz.

https://amigakit.amiga.store/product...6&currency=GBP

I did ordered it, let's hope it works.
Thanks for the link.

dalek · 26 March 2020, 01:44

Pretty sure they get them from China - not sure if they even test them. At least you can return it if it doesn't hit 40MHz.

FOL · 26 March 2020, 11:15

Quote:

Originally Posted by dalek

Pretty sure they get them from China - not sure if they even test them. At least you can return it if it doesn't hit 40MHz.

Yes, they are tested and yes they run and 40MHz all day long.

amiman99 · 14 April 2020, 06:47

Received my 68882 40MHz from Amigakit. Looks like it's working at 50MHz, no crashes so far running fpu enabled software.
I verified it with 33MHz and 50MHz oscillator, and got different results with SYSSPEED, which is good.
I'm using it on my A3000 with A3630 cpu board with replaceable oscillator. My onboard cpu is dead.

amigakit.com · 14 April 2020, 09:57

@amiman99

Thats great news, thanks for the order.

Thomas Richter · 14 April 2020, 12:44

Quote:

Originally Posted by amiman99

Received my 68882 40MHz from Amigakit. Looks like it's working at 50MHz, no crashes so far running fpu enabled software.

That does not mean much. Motorola did not put frequency codes on them for fun. It may seem to operate if FPU usage is mild, or uses only primitive arithmetic instructions, but it may fail under heavy load, or extended instructions such as transcendental functions that stress the internal logic much more than just elementary arithmetics. Yes, in general, the 68882 are quite tolerant in terms of overclocking, but that does not mean that yours is.

amigakit.com · 14 April 2020, 13:44

@Thomas_Richter

If he has any problem with it in future we offer warranty and after-sales support.

Kin Hell · 14 April 2020, 14:57

Quote:

Originally Posted by amigakit.com

@Thomas_Richter

If he has any problem with it in future we offer warranty and after-sales support.

Even for Over-Clocking beyond it's rated speed?

amiman99 · 14 April 2020, 20:37

To be honest, I will not run this FPU at 50MHz all the time. It will be sitting in the closet most of the time. I have a 40MHz oscillator on hand and if I see some problems I will swap it.
I'll use it once in a while to render some stuff and that is it.
The Chinese fpu I have would not even clock to 33MHz, even if it was labeled 40MHz. I'm pretty sure that it was a relabeled 16MHz.

I have A1200 accelerator (forgot the name) that has a surface mount 68030 16 or 25MHz, overclocked to 40MHz, at the factory, and it works fine.

25 March 2020, 03:34	#1
amiman99 Registered User Join Date: Sep 2009 Location: San Antonio, TX USA Age: 50 Posts: 1,184	Question about MC68882FN40A on Ebay Few years back I purchased new Freescale FPU MC68882FN40A on Ebay from China. I could never get it to work beyond 25MHz. I just found out that Laser etched labels are possibly fakes, and mine is Laser etched. I got a feeling that most MC68882FN40A chips on Ebay are fakes, so how do I spot a real one? Do real ones exist in 40MHz? Any tips? Thanks

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25 March 2020, 05:00	#2
dalek Registered User Join Date: Nov 2014 Location: NSW/Australia Posts: 462	All I do is buy multiples of the cheapest FPUs. Generally 1 in 4 will do 50MHz but your mileage may vary. Pretty much all the ones from China/HK on eBay / Aliexpress come from the same source or rebadged/relabelled/seconds stock.

25 March 2020, 11:55	#3
axel81l Registered User Join Date: Mar 2020 Location: Italy Posts: 104	I don't understand why you keep buying components from China ... especially vintage ICs They are able (personally verified) to sell you banal brushed and rebranded OTP 27C512. If you buy from China you need to know the market and know serious suppliers and not scammers

25 March 2020, 17:20	#5
amiman99 Registered User Join Date: Sep 2009 Location: San Antonio, TX USA Age: 50 Posts: 1,184	Can I overclock real 33MHz to 50MHz safely? Looks like real 33MHz are easier to find.

25 March 2020, 17:54	#7
axel81l Registered User Join Date: Mar 2020 Location: Italy Posts: 104	These IC goes out of production. You have three possibilities: 1)Take used and do what the Chinese do by putting the pins in a tin. 2) Find real IC used 3) Find real Brand new For a lot of Commodore ICs there are not a substitute ... and those that exist never 100% replicate the functionality of the original. Unfortunately, more and more of these ICs products will disappear .. and for all rarities, prices go up .. it is a law of the universal market.

25 March 2020, 18:07	#8
FOL PSPUAE DEV Join Date: Nov 2006 Location: Wales / UK Age: 45 Posts: 5,999	If your after PLCC version. Which work fine at 40MHz. https://amigakit.amiga.store/product...6&currency=GBP

26 March 2020, 01:44	#10
dalek Registered User Join Date: Nov 2014 Location: NSW/Australia Posts: 462	Pretty sure they get them from China - not sure if they even test them. At least you can return it if it doesn't hit 40MHz.

14 April 2020, 06:47	#12
amiman99 Registered User Join Date: Sep 2009 Location: San Antonio, TX USA Age: 50 Posts: 1,184	Received my 68882 40MHz from Amigakit. Looks like it's working at 50MHz, no crashes so far running fpu enabled software. I verified it with 33MHz and 50MHz oscillator, and got different results with SYSSPEED, which is good. I'm using it on my A3000 with A3630 cpu board with replaceable oscillator. My onboard cpu is dead.

14 April 2020, 09:57	#13
amigakit.com Registered User Join Date: Aug 2004 Location: www.amigakit.com Posts: 2,015	@amiman99 Thats great news, thanks for the order.

14 April 2020, 13:44	#15
amigakit.com Registered User Join Date: Aug 2004 Location: www.amigakit.com Posts: 2,015	@Thomas_Richter If he has any problem with it in future we offer warranty and after-sales support.

14 April 2020, 20:37	#17
amiman99 Registered User Join Date: Sep 2009 Location: San Antonio, TX USA Age: 50 Posts: 1,184	To be honest, I will not run this FPU at 50MHz all the time. It will be sitting in the closet most of the time. I have a 40MHz oscillator on hand and if I see some problems I will swap it. I'll use it once in a while to render some stuff and that is it. The Chinese fpu I have would not even clock to 33MHz, even if it was labeled 40MHz. I'm pretty sure that it was a relabeled 16MHz. I have A1200 accelerator (forgot the name) that has a surface mount 68030 16 or 25MHz, overclocked to 40MHz, at the factory, and it works fine.

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