All,
As others have doubtless discovered, these ICs are becoming unobtanium. I can get NOS of the LM3914 on e-bay, from domestic sellers, but I can’t be sure if they’re genuine. There are LM3914Vs for exorbitant prices, from East Asia, where, sadly, the counterfeit probability is much higher. It shouldn’t be hard to make an adapter, but I’d like to know if anybody has a photo of some genuine LM3914 or LM3914N, from National Semiconductor? Not that photos on e-bay are necessarily trustworthy, but it might help me rule some out. I can already tell that some appear to have had the labels sanded off, so who knows what those chips really are. The most trustworthy looking one is an RCA version, still sealed in the original packaging, but that one’s a bit pricey.
I plan on making a SIFT device, so that I can restore an old OS-8E oscilloscope. The nice thing is that the Navy still has the full operators/repair manual, so I know that there are some paper and foil caps and some bathtub caps. (Also a large number of screws with suspected Cadmium plating, which I replaced with stainless steel, yes I was careful)Â Â
Hi, I have a suggestion for you but it only apply if you have enough know-how and willing to do some legwork to achieve it 🙂 So here we go:  If you are a Patreon contributing member of MCL’s channel there is a version in particular (a TH 2018 version) of a cap leakage tester in which MCL has primarily used an LM3915N Barr-graph IC !!! (a DIL-18 package) and after that version he then switched to the LM3914V (the SMD version) but the reason is obvious : the LM3914V is an SMD part therefore smaller in size but otherwise they work in very similar ways. Back then, I had built both versions (the LM3915N as well as the LM3914V) and honestly, i couldn’t spot any visual difference at all !!!. My point is that the LM3915N might still be available at a Lower price than the extortionate price !!! you’ll pay for the LM3914V. So, if you have ever used and are familiar with some form of PCB design software you can use an LM3915N instead and mount it as an SMD package by simply bending all 18 pins @ 90 degrees outwards and therefore allowing you to solder it as if it was an SMD part. In other words, the whole idea is to MOD the SIFT PCB layout device (the original PCB design by MCL) in such a way so to allow for the above DIL-18 package to fit on the SMD PCB design. It can be done. I do similar MODS (myself) from time to time with some other designs too . However, first, I’d suggest that you breadboard the LM3915N part (only) to make sure that it works as intended. Now, having said all of the above, this is just an idea “providing that” you like experimenting with things and are not afraid of certain challenges. :).
TIPS to find some proven facts by MCL and to prove my point: in video 41 @ 37:16 (time stamp) MCL explains about both versions of the Barr-graph IC’s. in video 43 @ 9:22 (time stamp) MCL talks about the 2 IC’s (again) and their PCB layout comparison etc. Good Luck.
PS if you live in USA this is a place to buy it from:
In Europe, they are available to quite a few suppliers or (in my experience) I once (before) have purchased a whole bunch of them from AliExpress from 4 random sellers there, because they were (back then) the cheapest ones available and tested them all (on a testing rig on breadboard) and concluded that they were perfectly functional IC’s. But….again, it is entirely up to you to choose your own supplier.
@ovi4 Thanks. I’m not worried about experimenting with things. Also thanks for pointing out a legit source. I have to get some name brand toner for my printer as it prints much too lightly to make good PCBs, no matter which settings I use (it was fine when I used the expensive stuff), so I was going to experiment on the breadboard for a while, anyway.
I didn’t want to wait for the 7 weeks that jameco.com was quoting, so I found some LM3914Ns on e-bay that were supposedly pulls, but looked exactly like the series that Mr. C used in video 41. After watching video 130 on how to spot fakes, these ones looked the most authentic. There were some NOS ones of the same series, but the seller was charging $30 for shipping, for $15 worth of stuff. 🤬Â
@seryddwr Standard move. That way they can ensure they get closer to the price they want per item while appearing to undercut others on the site.
You could try a place called “octoparts”. They very often have “obsolete” bits and pieces.Â