Faint IC Marking

Aug 08, 2016 33 Replies

Why are many ICs marked so faintly? I have seen any number of devices where they are hard to read even if angled in the light just so. I bought an open frame power supply and while inspecting it found what might be a missing component, an 0603 maybe. One of the ICs next to it has markings so faint I have not been able to read them at all.



The irony is that the various resistors are marked very legibly and other than the small size, I have no trouble reading them. So why can't the ICs be marked so humans can read them?


Rick C

This may be worth trying, more for reading markings that are hidden in narrow gaps on over-populated boards, Tx, relays etc. Stretch some thin plumber's PTFE tape over the IC and lightly rub over with a small piece of wood. The raised print turns the ptfe clear with the local pressure , on rubbing, so introducing contrast

Because resistors (normally just 0603 and above) are ink printed with the value. Most IC package legends these days are laser etched removing or roughing up the top layer slightly.

They burn the markings into the case using a laser, it doesn't work well, but it works well-enough.

chip resistors are printed, once upon a time ICs were printed too

This email has not been checked by half-arsed antivirus software

To save on the cost of adding pigmentation to the markings.

Chalk, white correction fluid, and white paint all work: The IC's are marked with a laser which roughs up the surface. All you need to do is add some filler or pigment into the rough areas.

There are some other ideas listed in the above article, such as UV flashlights, cameras, and magnifiers. I haven't had much luck with these.

Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Which, I believe, is an anti-counterfeit measure -- printed-on markings are easier to modify or outright fake; the laser-cut numbers are an attempt to at least keep the real amateurs out of the chip-counterfeit game.

Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!

That doesn't explain illegible laser markings. If you can't see them they can't help you determine the chip has been remarked.

Rick C

I know what you mean. I don't know why folks have chosen to do it that way.

Maybe they don't care about you if you don't have automated assembly.

Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!

The assembly is automated, but it can make the diagnosis easier if you can just read the part numbers rather than having to go to a BOM... especially if you don't have it. lol

Rick C

Have you tried different kinds of light ? I mean like pure red or blue LED or something like that.

Also, just occurred to me what might help is bird s*it. That was our pet na me for heat sink compound. Maybe put a dab on that on it and then wipe it o ff and the the bird s*it stays in the etched places.

Another possibility is a super good camera and image editing software. I've been able to bring up a few things with a crap camera, like 5 MP or someth ing like that and software so old it ran in Windows 3.1.

And to the reason for this, someone said it makes it harder to counterfeit, sure, but also, most manufacturers do not want their product serviced, the y want to sell another one. I would say it is unusual that you have to reve rse engineer something you engineer, but these days anything is possible.

Yeah, I have access to the docs for the boards I design, but it is strange having to go back to the BOM to see what part is on the board in front of me. The chip vendors don't have much interest in the planned obsolescence of their customer's products. Yeah, they might sell a few more, but more likely is bad will from those who can't read the damn things.

I already tried the photo technique. There's just not enough visible marking to pick it up. Whatever. I was taking the photo to ask the vendor if a part was missing. There was a big ball of solder on one pad of a small passive part location and the other pad looked like it had the corner of a part pressed into the solder like the part never wetted fully and then fell off. I thought it was strange that there was so much solder there. They said this part is not populated, so I guess I'll fire it up and see if it smokes.

Rick C

Could be worse though - we recently received a notification from Xilinx saying that some of their parts are changing over to a QR code on the lid. They will still have the basic part number, but manufacturing lot, place of manufacture, date code and speed grade will no longer be human- readable.

I don't know whether that's due to cost reduction, anticounterfeiting measures or just that they hate their customers.

Allan

Is it going to be readable by your cell phone (info online)? If so, I don't see it as a big deal and could even be a benefit.

Make it harder for the counterfeiters to read the markings so they can copy them :-)

Like the anti-counterfeiting stuff in US currency, it just creates a better class of counterfeiters.

The QR decoding can be done by an app on a phone, but that only gives the serial number. One must register and login to their portal to be able to decode the serial number into anything useful. This means that they can track who's looking at which devices.

Allan

When you're selling security to [long list of countries, some of which don't like each other, redacted], you tend to care about who can see what's going where. The customers do care, which means that I have to care too.

Allan

Plus over here there are super scary export regulations that can land you in jail for 10 years _per violation_. Big FPGAs aren't on the US Munitions List (22 CFR 1, section 121), but they are on the Commerce Department list of controlled dual-use items, so I expect this is some arrangement Xilinx has with the US Gov. Discovery Semiconductor has the same registration requirement for (according to them) the same reason. Sure makes them a pain to deal with, though.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

So in theory a black van could shows up at your door because some guy in DPRK looked up a device that was sold to you, scary..

-Lasse

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