Over a year ago I purchased three of the four-digit Chinese IN-12 clocks with the LED background lights. Of those, two of them were complete junk and AliExpress refunded my money so I only paid USD$20 for the one good clock (I offered to return the bad ones but they did not want them - surprise). One of the bad ones just stopped working (appears to be a CPU issue though one tube lights up so the tiny quarter sized HV power supply is good and salvageable) and the other loses around 10 minutes every few hours. It cannot keep accurate time at all. Unlike another Chinese board I have for IN-14's that is rock solid and does not lose any time at all over several weeks of operation. I figure the clock that cannot keep time can eventually be fixed by replacing the DS3231M chip. I picked one up on eBay for the day when I can find someone who has an SMD rework setup to that I can remove the old chip and install the new one. But this is definitely a case of a worthless DS3231M being used in products. I assume the manufacturer wound up with a bunch of counterfeit or salvaged DS3231M chips and just passed them off. Lucky for me, one of the chips does work properly.
On Friday, January 1, 2021 at 11:52:30 AM UTC-5 gregebert wrote: > Happy New Year, everyone. If you built a new clock last year with a used > or cheap DS3231, check the date to make sure it's correct. > > I posted about this 2 years ago when I found another fake clock chip. > > On Friday, January 25, 2019 at 3:35:06 PM UTC-8 Tony Adams wrote: > >> There are indeed some strange 'counterfeits' around. Maybe they were a >> deliberate attempt to confuse reverse engineering of some product, but >> never used? or it could have been a simple mistake. >> >> I have a few thousand MPSA92 which have been remarked from MPSA42, >> with the 4 and 9 superimposed. They work perfectly as PNP HV >> transistors so it's possible somebody just forgot to change the >> engraver text and the mistake wasn't noticed until they had a large >> pile of mismarked PNP MPSA42s. >> >> Tony. >> >> On Fri, 25 Jan 2019 22:38:43 +0000, you wrote: >> >> >Hi Bill, >> > >> >Indeed, it seems bonkers. I assume it's because someone has a huge stash >> >of open collector output 74 series shift registers, and either thinks >> >they're the same, or that most people won't notice the difference. >> > >> >I bought two batches of 500 of them, from two different chinese >> suppliers, >> >and they are all exactly the same, having the same laser engraved batch >> >number even. To be fair, the prices were suspiciously good, but I wasn't >> >banking on fake shift register ICs.... >> > >> >They are badged as TI SN74HC595N, and batch GM1807FSF. >> > >> >I have some 'normal' SN74HC595N, and swapping these out for the real >> ones >> >generates the expected behaviour ( and yes, inv G is indeed pulled low). >> > >> >With the 'fake' ones, they will appear to work OK with a pull up >> resistor >> >present (as you'd expect with an open collector output), but are unable >> to >> >source any current. >> > >> >I thought it was just me, but then I googled GM1807FSF and found someone >> >else (in German) having the same problem! >> > >> >https://www.mikrocontroller.net/topic/463936 >> > >> >David >> > >> >On Fri, 25 Jan 2019 at 22:24, Bill van Dijk <theold...@gmail.com> >> wrote: >> > >> >> That is really weird. Please understand I am not questioning what you >> are >> >> saying, but perhaps there is another explanation. The 74LS596 (I have >> never >> >> seen an HC version) is indeed an open collector chip similar to the >> >> 74HC595, which is a tri-state device. On the 74HC595 the inv G (pin >> 13) >> >> should be held low for normal operation. If it goes high for any >> reason, >> >> the output will float in tri-state mode, similar to what an open >> collector >> >> would look like. As you say, I can’t for the life of me not figure why >> >> anyone would bother to rebadge those chips especially since there does >> not >> >> seem to be an economic one (which is usually the motivation). >> >> >> >> >> >> >> >> Bill >> >> >> >> >> >> >> >> *From:* neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] >> *On >> >> Behalf Of *David Pye >> >> *Sent:* Friday, January 25, 2019 4:12 PM >> >> *To:* neoni...@googlegroups.com >> >> *Subject:* Re: [neonixie-l] Re: Counterfeit RTC modules >> >> >> >> >> >> >> >> It seems even things barely worth faking are being faked also. >> >> >> >> >> >> >> >> I have a bag of 500 74HC595 shift registers, that are actually >> rebadged >> >> 74HC596s (as in, open collector, SINK, not SOURCE-capable). >> >> >> >> >> >> >> >> Which are useless for my application :-( >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> Groups >> >> "neonixie-l" group. >> >> To unsubscribe from this group and stop receiving emails from it, send >> an >> >> email to neonixie-l+...@googlegroups.com. >> >> To post to this group, send email to neoni...@googlegroups.com. >> >> To view this discussion on the web, visit >> >> >> https://groups.google.com/d/msgid/neonixie-l/008501d4b4fc%24bb636a80%24322a3f80%24%40gmail.com >> >> >> < >> https://groups.google.com/d/msgid/neonixie-l/008501d4b4fc%24bb636a80%24322a3f80%24%40gmail.com?utm_medium=email&utm_source=footer> >> >> >> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> >> >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/d411c35b-8c1b-4bec-80a8-5f666b78e6d9n%40googlegroups.com.
