Fake AT28HC256E-12SI? + MAX EPM7128SLC84-15 - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 18, 2020, 08:39:33 pm
content: I bought some AT28HC256E-12SI AT28HC256E 32K x 8 High Speed Parallel EEPROM SOP-28 on EBAY but for the life of me I cannot get the things to program using my MiniPro programmerI also tried to write some software in my homebrew chip tester but get different but also failing results.Any suggestions on how to test these before asking for a refund?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 18, 2020, 08:43:24 pm
content: If I was being really paranoid I would say these have been sanded down and then reprinted?? (It's difficult to know how much their travel down the plastic tube would have caused abrasion)

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 20, 2020, 04:10:28 pm
content: A couple more pictures as I vent my frustration!and

author: wraper
author_rank: Unknown
timestamp: July 20, 2020, 04:28:47 pm
content: Looks blacktopped. Try rubbing with acetone or similar solvent. Date code is certainly fake since lead surface doesn't look as something fresh.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 20, 2020, 07:09:27 pm
content: I tried rubbing the top with 99.9% iso propyl but didn't seem to get any black paint off.I looked underneath and saw it is marked "AC" and "22".... I wonder if that provides any clue as to provenance?Certainly doesn't seem to work... with 5V to p28 and GND to p14 I don't seem to see any action and it possibly (human error possible) gets warmPSIgnore the angle of the top pins... that's my doing!

author: magic
author_rank: Super Contributor
timestamp: July 20, 2020, 09:12:20 pm
content: Is it just me or does the bottom texture look more grainy while top is more flat, as if sanded?

author: wraper
author_rank: Unknown
timestamp: July 20, 2020, 09:53:28 pm
content: Quote from: NivagSwerdna on July 20, 2020, 07:09:27 pmIsopropyl might be too weak. Also if chip was heated, then blacktopping becomes much more robust against solvents.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 21, 2020, 08:31:29 am
content: I had a scratch with my finger nail in both corners and also in the notch and the coating comes awayThieving F***ers!

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 21, 2020, 08:11:40 pm
content: OK so I took myself to one side and said..."And what other too good to be true stuff have you bought in the past and is now sitting in the parts store for future projects?"and I said... "Oh well I did buy rather a lot of some MAX7000 series CPLDs for future 5V arcade board fixing projects"and I said... "Better test them then!"and 2 days later... 100% FAKEThieving BAS***DS!!!

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 23, 2020, 05:20:09 pm
content: I reordered my AT28HC256 from Farnell and my AT28HC256F-90SU arrived today.4x the price of the fakes...Put it in the programmer... worked first time.And it even fits the footprint on my PCBLessons learnt!PSI think I have a couple more fakes (6502s?) still in my collection but my MAX7128SLC84s and AT28HC256E-12SI are history)

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 30, 2020, 01:02:34 pm
content: I recently received some...these seem to be TOO wide? More fakes?

author: wraper
author_rank: Unknown
timestamp: July 30, 2020, 01:15:20 pm
content: Package looks like original

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 30, 2020, 03:23:20 pm
content: Using my chiptester... they don't seem to work... so I'm 99% sure they are fakeI have changed my mind... they are mostly OK... I did have one dud but the rest seem to pass the tests OK.So I'm paranoid about Chinese supplied chips now... oh dear.