Easy way to read chip IDs - Page 1
Forum section: electronics / beginners

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 27, 2019, 04:09:44 am
content: Don’t know if this is old trick or not, but anyway I found reading IC numbers is often difficult. So I wipe a very thin coat of heat sink grease across the top and the numbers instantly pop. See before and after image below.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: December 27, 2019, 06:01:25 am
content: Another trick is to stick on a piece of transparent Scotch type tape.

author: AVGresponding
author_rank: Super Contributor
timestamp: December 27, 2019, 10:42:08 pm
content: The heatsink grease trick is quite well known, but works best for laser etched chips.I must confess I never heard of the sticky-tape (no brand names here!) method before, I'll have to try it.Another method that can work with older non laser etched chips that have worn markings is to use a different wavelength light source, coupled with a phone camera or webcam. These cameras are sensitive to infra red wavelengths which can be useful.Be careful around those old eproms if you're using a UV light though!

author: tooki
author_rank: Super Contributor
timestamp: December 31, 2019, 12:54:00 pm
content: Quote from: ThickPhilM on December 27, 2019, 10:42:08 pmI assure you, both Scotch and Tesa brand tapes are readily available in England. I'm also sure you're familiar with the concept of genericized trademarks, like scotch tape and kleenex in USA, and tesa film and hoover in the UK. Ergo, "I wanted a rude username" didn't mean it had to be a specific brand.(And for sure, there's no rule against brand names on the forum.)

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 01, 2020, 12:11:46 am
content: Yes, referred to it as Scotchtypetape because I wasn't sure if "sticky tape" is an Australianism.Probably any thin transparent foil would work. Cling wrap might be superior for all we know. More testing required.

author: tooki
author_rank: Super Contributor
timestamp: January 01, 2020, 01:18:16 pm
content: I doubt cling wrap (commonly called by the genericized trademark "Saran Wrap" by many Americans, muahahahaha) would work better. I'm pretty sure it's the total elimination of the air gap by the (fresh) adhesive that makes the text visible.P.S. Americans definitely also say "sticky tape". Or just "tape", if context ensures no other kinds of tape could be understood.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 07, 2020, 08:59:15 am
content: You're right, just tried it and cling wrap completely fails to adhere to the microcontroller's matte surface. Tape works as expected.

author: AVGresponding
author_rank: Super Contributor
timestamp: January 07, 2020, 06:14:35 pm
content: You misunderstand me, I wasn't berating anyone for mentioning brand names, I was merely stating (in what I had hoped was a humorous way) that I had no brand preference or recommendations!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 07, 2020, 08:53:33 pm
content: A simple method that often works is to change the angle under which you view your component.Often you can easily find an angle in which the text reflects more (or less) light than the surrounding package, which makes it stand out.Another way is to work with polarised light. (with a rotating polaroid filter).Especially when this is built into your microscope setup it's very convenient fast & easy to use, especially because you do not have to use "externall stuff" such as grease, water or tape.You could even rotate the polaroid filter with a foot pedal.

author: wraper
author_rank: Unknown
timestamp: January 07, 2020, 08:56:53 pm
content: Instead of contaminating parts with crap, you could simply clean them with alcohol or other solvent to make marking visible.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 08, 2020, 05:34:43 am
content: No-clean flux followed by scrubbing with alcohol seems to have the opposite effect: the surface of the chip becomes a matte grey and markings aremuchless legible. At least in my experience.

author: wraper
author_rank: Unknown
timestamp: January 08, 2020, 01:07:01 pm
content: Quote from: I wanted a rude username on January 08, 2020, 05:34:43 amLaser marking is easily visible on clean surface, especially if light falls under angle. If it is not visible, most likely you just spread contamination but not cleaned it. If there is a lot of flux, follow with dry wipe after wetting the surface. If not enough, follow with slightly wet wipe to clean remnants of contamination. Surface should be matte if surface of plastic is not glossy to begin with.

author: AVGresponding
author_rank: Super Contributor
timestamp: January 08, 2020, 06:04:21 pm
content: Yes, a good (but gentle) clean will help with laser etched markings, but if they are older, printed ones, you might just remove the last chance of reading them!

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 09, 2020, 12:46:28 am
content: The problem is that the flux and/or brushing with alcohol removes the white paint from within the laser engravings. They can still be read under angled light, but less easily than before.Of course, this batch of 50 AVRs could simply be counterfeit.They work, but while all have the same markings on the top surface, the bottom surfaces have a few different markings. Maybe genuine ICs would use paint resistant to these solvents.

author: wraper
author_rank: Unknown
timestamp: January 09, 2020, 12:52:02 am
content: Quote from: ThickPhilM on January 08, 2020, 06:04:21 pmMild contamination over paint marking does barely anything to readability. In such case smearing thermal paste certainly won't do anything to improve visibility, only make it worse. And my comment was about laser marking only to begin with.

author: wraper
author_rank: Unknown
timestamp: January 09, 2020, 12:53:00 am
content: Quote from: I wanted a rude username on January 09, 2020, 12:46:28 amWhat paint, LOL? Laser marking = no paint.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: January 09, 2020, 01:36:08 am
content: Wait, really? I didn't know that. So the lighter colour within the engravings is due to a change in surface texture or chemical composition caused by ablation or localised heating? And the flux and/or brushing with alcohol removes that surface effect.We should remember that there are different reasons why an IC's marking may be hard to read. Alcohol may help if it's downrightdirty, but that's unlikely for chips straight from the tape/tray ...