Author Topic: Easy way to read chip IDs  (Read 2196 times)

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Offline Ground_LoopTopic starter

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Easy way to read chip IDs
« on: December 27, 2019, 04:09:44 am »
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.
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Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #1 on: December 27, 2019, 06:01:25 am »
Another trick is to stick on a piece of transparent Scotch type tape.
 

Offline AVGresponding

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Re: Easy way to read chip IDs
« Reply #2 on: December 27, 2019, 10:42:08 pm »
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!   :-DD
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Offline tooki

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Re: Easy way to read chip IDs
« Reply #3 on: December 31, 2019, 12:54:00 pm »
I must confess I never heard of the sticky-tape (no brand names here!) method before, I'll have to try it.
I 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.)
« Last Edit: December 31, 2019, 12:55:47 pm by tooki »
 

Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #4 on: January 01, 2020, 12:11:46 am »
Yes, referred to it as Scotch type tape 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.
 

Offline tooki

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Re: Easy way to read chip IDs
« Reply #5 on: January 01, 2020, 01:18:16 pm »
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.
 
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Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #6 on: January 07, 2020, 08:59:15 am »
You're right, just tried it and cling wrap completely fails to adhere to the microcontroller's matte surface. Tape works as expected.
 
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Offline AVGresponding

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Re: Easy way to read chip IDs
« Reply #7 on: January 07, 2020, 06:14:35 pm »
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!
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Offline Doctorandus_P

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Re: Easy way to read chip IDs
« Reply #8 on: January 07, 2020, 08:53:33 pm »
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.
 
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Offline wraper

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Re: Easy way to read chip IDs
« Reply #9 on: January 07, 2020, 08:56:53 pm »
Instead of contaminating parts with crap, you could simply clean them with alcohol or other solvent to make marking visible.
 
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Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #10 on: January 08, 2020, 05:34:43 am »
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 are much less legible. At least in my experience.
 

Offline wraper

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Re: Easy way to read chip IDs
« Reply #11 on: January 08, 2020, 01:07:01 pm »
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 are much less legible. At least in my experience.
Laser 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.
« Last Edit: January 08, 2020, 01:09:28 pm by wraper »
 

Offline AVGresponding

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Re: Easy way to read chip IDs
« Reply #12 on: January 08, 2020, 06:04:21 pm »
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!
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Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #13 on: January 09, 2020, 12:46:28 am »
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. ;D 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.
 

Offline wraper

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Re: Easy way to read chip IDs
« Reply #14 on: January 09, 2020, 12:52:02 am »
if they are older, printed ones, you might just remove the last chance of reading them![/color][/b]
Mild 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.
« Last Edit: January 09, 2020, 12:59:46 am by wraper »
 

Offline wraper

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Re: Easy way to read chip IDs
« Reply #15 on: January 09, 2020, 12:53:00 am »
The problem is that the flux and/or brushing with alcohol removes the white paint from within the laser engravings.
What paint, LOL  :-//? Laser marking = no paint.
 

Offline I wanted a rude username

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Re: Easy way to read chip IDs
« Reply #16 on: January 09, 2020, 01:36:08 am »
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 downright dirty, but that's unlikely for chips straight from the tape/tray ...
 


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