W27C512 EEPROM Frustrations

[james_s]

i can see the value in some components, but for the most part it seems like setting up to counterfeit money, but only producing dollar bills.....

with a bit more effort you could counterfeit something worth the profit, or just make an authentic product......

and i have no issues with used components, i use them often in repairs, but i know they are used and they work just fine... usually, but that is the risk of used.

If you have 100,000 useless junk ICs like mask ROMs or some other worthless part and loose morals, you can run the lot through a machine that sands off the top and marks them with a new part number and now you've got something that was worth $0 that you can now sell for $1 or more each, that's $100k minus whatever you spent re-marking them which is often not much in volume. It can be very profitable, even for low value parts.

Not all parts bought direct from China are suspect but certain types of parts nearly always are. Older parts that are no longer produced and still in high demand are most commonly counterfeit but you can find fake jellybean transistors if only because marking a big pile of reject transistors as 2N3904s and selling packs of 50 for a few dollars is more profitable than throwing them away.

[edavid]

It's a lot easier if you have either a known good programmer or known good ICs 

But if you do want to build your own programmer, why not choose 5V only parts like the SST39SF010A?  They are still very cheap.

[CRCLARKE]

It's a lot easier if you have either a known good programmer or known good ICs 

But if you do want to build your own programmer, why not choose 5V only parts like the SST39SF010A?  They are still very cheap.

well i am still pretty new to this and don't have a ton of experience with chip options. i checked out that chip you mentioned, what a great option!! i think i will pick some up, but my current project requires a 28 dip, can you recommend one to me?  and maybe some other options?

[mikerj]

I watched the video (posted above) about counterfeit components........ and it raised 2 questions to me.....

1. Why relabel something other than what it is? After all, it already has a label and proper function, it would seem easier to sell an orange as an orange rather than trying to paint it to look like an apple.

Because apples may be in higher demand and therefore worth more money than oranges.

2. Unless the they have a fully automated system, it seems impossible to profit from manual chip salvage in bulk. If it took only a minute to refurbish each component, then even at a $1 each per component, the labor required is BARELY worth the return.

I can buy almost any new component or even IC's for a $1 or less.

So why not buy your 27C512 brand new for $1?  You simply can't.

[edavid]

It's a lot easier if you have either a known good programmer or known good ICs 

But if you do want to build your own programmer, why not choose 5V only parts like the SST39SF010A?  They are still very cheap.

well i am still pretty new to this and don't have a ton of experience with chip options. i checked out that chip you mentioned, what a great option!! i think i will pick some up, but my current project requires a 28 dip, can you recommend one to me?  and maybe some other options?

I don't know of a 512K bit, 28 pin, 5V only part, but you can consider:

AT29C256 256K 28 pin 5V
SST27SF512PG 512K 28 pin 5V/12V, but not quite as finicky as W27C512

[wraper]

I don't know of a 512K bit, 28 pin, 5V only part, but you can consider:

AT29C256 256K 28 pin 5V
SST27SF512PG 512K 28 pin 5V/12V, but not quite as finicky as W27C512

And have the same counterfeiting issues as both are obsolete as well.

[edavid]

I don't know of a 512K bit, 28 pin, 5V only part, but you can consider:

AT29C256 256K 28 pin 5V
SST27SF512PG 512K 28 pin 5V/12V, but not quite as finicky as W27C512

And have the same counterfeiting issues as both are obsolete as well.

At least they have signatures and are 100% testable.  For a hobby or repair project, isn't that good enough?

What would you suggest as an alternative if a DIP28 part is needed?

[CRCLARKE]

I don't know of a 512K bit, 28 pin, 5V only part, but you can consider:

AT29C256 256K 28 pin 5V
SST27SF512PG 512K 28 pin 5V/12V, but not quite as finicky as W27C512

Thank-You edavid, 

I have added those to my list!


Does anyone else know of some other good options for dip eeproms?

[richnormand]

You might enjoy reading this primer:
http://muanalysis.com/wp-content/uploads/2019/01/Counterfeit-or-retrofit.pdf

Note for full disclosure: I know the author.

[wraper]

At least they have signatures and are 100% testable.  For a hobby or repair project, isn't that good enough?

Both SST27SF512 and W27C512 have ID code, so moot point. What I know there is virtually no genuine SST27SF512 in DIP package on ebay. Actually you'll get re-marked W27C512 at best as supply of SST27SF512 is much scarcer and it's more expensive. Or more likely re-marked OTP EPROM.

What would you suggest as an alternative if a DIP28 part is needed?

OTP AT27C512R from Microchip (Atmel) which is still in production if you can live without re-programming. Or something not in DIP.

[edavid]

At least they have signatures and are 100% testable.  For a hobby or repair project, isn't that good enough?

Both SST27SF512 and W27C512 have ID code, so moot point. What I know there is virtually no genuine SST27SF512 in DIP package on ebay. Actually you'll get re-marked W27C512 at best as supply of SST27SF512 is much scarcer and it's more expensive. Or more likely re-marked OTP EPROM.

So far I have had a 50% success rate buying SST27SF512s on AliExpress @ $0.60.  I just got refunds on the bad ones and moved on.  For hobby projects that's OK.  Fortunately there are not many cases where you need DIP28 512K parts.

It's easy to find real windowed 27C512s in the US, so I don't think I would bother buying OTPs.  Flash is so much more convenient though.

[CRCLARKE]

So far I have had a 50% success rate buying SST27SF512s on AliExpress @ $0.60.  I just got refunds on the bad ones and moved on.  For hobby projects that's OK.  Fortunately there are not many cases where you need DIP28 512K parts.

It's easy to find real windowed 27C512s in the US, so I don't think I would bother buying OTPs.  Flash is so much more convenient though.

agreed

Its much easier to deal with counterfeits when you know when and where they come up. At least you can hedge you bets and expect losses

[hermitengineer]

If you're okay with one-time programming, Microchip still makes a 27C512.  Or, at least, Mouser still has them in stock.  On the bright side, that saves you from building an eraser.

https://www.mouser.com/Semiconductors/Memory-ICs/EPROM/_/N-488ye?Keyword=27c512&FS=True