Repairing industrial hydraulic sequencer, many ST ULN2004A's, not sure if discontinued, helpful to know if worn out. How to arrive at date code from print top of plastic DIP ULN2004A GK651288 VW GK CHN is 1988 etc ?

[Peter BENSCH]

Welcome, @Niche​, to the community!

Surprisingly, the ULN2004A is still in production. A quick search on the internet should bring some suppliers to light.

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter

[Niche]

Yes I thought it might still be in production but, doesnt address the question which is

how do I arrive at the date of manufacture from the numbers printed on the DIP top ?

Looking forward to knowing date of manufacture from the coding information on the chip,

as its important for industrial equipment of this era as part of risk assessment management ie the conventional MTBF saddle curve etc.

From patterns on other ST devices and similar to other manufacturers it appears

as Week 51 of 1998 though with the preceding 6 maybe the factory, no of years since inception but, that doesnt matter - need the year of manufacture at least, thanks

Ah just noticed u are employee - great - please advise date ???

BTW: Would like to change the web site inserted nickname, cant see how to do that, any ideas ?

Mike

[Peter BENSCH · Accepted solution]

Sorry, I had understood the question differently and interpreted it as a question about substitutes.

Anyway: the date code in this case can be found in the second line, 3...5th character and is read as YWW.

So in your example GK651288 => year ending with 6 (1996, 2006, 2016) and calender week 51. For a further narrowing of the decade, one would have to have the label of the packaging, but unfortunately it is not possible to determine this from the marking on the component.

The last three characters here code the internal number of the backend, so the 288 has nothing to do with the date.

Nickname - you can change it in your profile:

My Profile > Update my Profile > Nickname

Good luck!

/Peter

[Niche]

That's good to know on date range, thanks :)

So its unclear re best practice replacement re saddle curve MTBF etc It runs a big machine yet usually does it reliably despite really old simple non PLC, non Micro sequencer...

Board pics here:- http://members.iinet.net.au/~erazmus/libertyi/

Tried the profile change when first registered, didnt have option then but, now it does - so have updated, worked fine too, profile hair's greyer now, though 20micron thicker as on copper supplements :)

The hydraulic steel cutter/crusher manufacture states 2011 so likely the semis at least 2006 manufacture however, the circuit boards appear as if earlier given the resistor forms maybe from a general batch production of selectable valve sequencers stocked batch much earlier - seen that sort of thing circa 1984 when I was chief engineer at Pretron Electronics designing CNC depth/angle controllers for press brakes. It could well be older than 1996 as I've seen your device even earlier...

So I'm curious when the ULN2004A series was first manufactured (& minus the A), would it have been 1986 or so as I seem to recall that as an SGS type on a Pace-16 micro by NS back then - first one globally to run Nucleonics beta particle absorption on iron ore falling curtain mass flow Mt Newman mining, Western Australia ?

Regards

Mike

Perth, Western Australia

[Peter BENSCH]

Whew, that's off my record. I've known about the ULN2004 since the 1980s too, but my earliest entry on the ULN2004A from SGS is from 1998, so I assumed that in your case 6 stood for the three mentioned decades.

BTW: please remember that the community is a public forum and can be viewed by anyone worldwide. So personal data should only be posted via PM, never in the forum.

Regards

/Peter

[Niche]

Thanks for reply, I'm puzzled re your comment "..so I assumed that in your case 6 stood for the three mentioned decades" ? The 6 origin is the print on the DIP, your point about it on 1996 & your example of 3 decades - so Im curious what assumption did you make...

I have observed the design style on the boards for repair as per my link appears they are older as in 1980's, so maybe 1986 manufacture at earlier as that appears consistent with the style of discrete components on the board and consistent with the 10 year period of your date codes ending in 6 for year..

Good to remind re personal, though there's nothing I've posted I consider of personal value, the IP patents all expired & all of which obtainable via google & Curtin Uni and without any sort of leverage value either. The link to a members repository handled by an Australian ISP erazmus a 16th century philosopher, if there is anything you or ST consider personal leverage able to be misused then feel free to PM me & I'll remove particular elements pronto, np :)

Cheers

[Peter BENSCH]

By "6 stood for the three mentioned decades" in my earliest entry of 1998 I meant 1996, 2006 and 2016. I can't rule out that SGS produced the ULN2004A before then, so 6 would stand for 1986. Unfortunately, due to a lack of information, it is not possible to make a statement on this.

Personal data: I just wanted to make sure that you are aware of it. Everything is fine if nothing personal is included. :thumbs_up:

Regards

/Peter