Author Topic: Someone in 1988 had a boring job...  (Read 5247 times)

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Offline pcprogrammer

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Re: Someone in 1988 had a boring job...
« Reply #25 on: October 15, 2022, 06:08:31 am »
.... you only forgot to add the number or sleeve once,and only discovered you'd forgot it after the final wire was soldered to the connector

That is a bit like always telling others when making cables not to forget to slide the connector cap on before soldering, and what do you do yourself, forget to slide on the cap :palm:

Offline TerraHertz

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Re: Someone in 1988 had a boring job...
« Reply #26 on: October 15, 2022, 07:03:54 am »
When you forgot to put a 'revision #' on the silkscreen, so you mark a pin as the rev #?

The idea 'insulate the pin from a screw' doesn't work, since there are two pins with identical spacing from the hole. And the screw/washer would contact the solder fillet anyway.
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Offline CatalinaWOW

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Re: Someone in 1988 had a boring job...
« Reply #27 on: October 15, 2022, 07:54:07 am »
Could this be something like the false streets placed in maps to detect plagiarism?  Something that has no real purpose placed there.  Then in court a counterfeiters inability to explain the purpose would be evidence.
 

Online langwadt

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Re: Someone in 1988 had a boring job...
« Reply #28 on: October 15, 2022, 10:12:43 am »
When you forgot to put a 'revision #' on the silkscreen, so you mark a pin as the rev #?

The idea 'insulate the pin from a screw' doesn't work, since there are two pins with identical spacing from the hole. And the screw/washer would contact the solder fillet anyway.

if you look closely you can see that the other nearby pins are connected to the same ground plane as the mounting hole
 
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Offline PlainName

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Re: Someone in 1988 had a boring job...
« Reply #29 on: October 15, 2022, 11:03:56 am »
Quote
Could this be something like the false streets placed in maps to detect plagiarism?

There's an idea!

Hmmm. Maybe I should say all my mistakes are false streets rather than apologise for the cockups.
 

Offline AndyBeez

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Re: Someone in 1988 had a boring job...
« Reply #30 on: October 15, 2022, 02:45:13 pm »
Not as much fun as this guy somewhere in south east asia was having.

I was asked by a nieghbour if I could fix their solar light? As you can see from the image, there was an ingress of water/condensation and, the light was long gone to the great WEEE pile in the sky. Originating from Britain's defunked Poundworld store, it was not made from top quality materials. So why then did someone go to all the trouble of grinding off the chip numbering? From the component layout it's a jellybean solar light chip - like the QX5252. Another identical light was ground in the same way.
Pehaps the IC's were stolen, were on a technology export blacklist or, would be traced back to the slave labor camp were someone is making these for half-a-dime a piece? Whatever, there be a happy man out there ;D
« Last Edit: October 15, 2022, 02:47:26 pm by AndyBeez »
 

Offline james_s

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Re: Someone in 1988 had a boring job...
« Reply #31 on: October 15, 2022, 06:05:38 pm »
There's always some idiots out there that think grinding the number off an IC does anything to stop someone from reverse engineering something. I'd probably reverse engineer it and replace the IC out of spite.
 
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Offline CatalinaWOW

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Re: Someone in 1988 had a boring job...
« Reply #32 on: October 15, 2022, 10:06:48 pm »
There's always some idiots out there that think grinding the number off an IC does anything to stop someone from reverse engineering something. I'd probably reverse engineer it and replace the IC out of spite.

There is no method for anti-tampering which stops reverse engineering.  Grinding numbers off of chips makes enough trouble to stop the only slightly motivated.  It may add an increment of cost or time to the cost of copying devices with other means of protection.

Just because you can and have.overcome this method doesn't mean it didn't meet the objectives of the originator.  Which might have been something as simple as a few days advantage in time to market
 

Offline james_s

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Re: Someone in 1988 had a boring job...
« Reply #33 on: October 15, 2022, 10:09:26 pm »
There is no method for anti-tampering which stops reverse engineering.  Grinding numbers off of chips makes enough trouble to stop the only slightly motivated.  It may add an increment of cost or time to the cost of copying devices with other means of protection.

Just because you can and have.overcome this method doesn't mean it didn't meet the objectives of the originator.  Which might have been something as simple as a few days advantage in time to market

It motivates me to reverse engineer something. On more than one occasion I have taken the effort to reverse engineer a device only because someone had ground the numbers off the ICs, if not for that I wouldn't have bothered but I took it as a challenge. The amount of "protection" that method provides is absolutely trivial, all it really does is make it more difficult for a novice to repair.
 
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Offline CatalinaWOW

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Re: Someone in 1988 had a boring job...
« Reply #34 on: October 15, 2022, 11:58:12 pm »
There is no method for anti-tampering which stops reverse engineering.  Grinding numbers off of chips makes enough trouble to stop the only slightly motivated.  It may add an increment of cost or time to the cost of copying devices with other means of protection.

Just because you can and have.overcome this method doesn't mean it didn't meet the objectives of the originator.  Which might have been something as simple as a few days advantage in time to market

It motivates me to reverse engineer something. On more than one occasion I have taken the effort to reverse engineer a device only because someone had ground the numbers off the ICs, if not for that I wouldn't have bothered but I took it as a challenge. The amount of "protection" that method provides is absolutely trivial, all it really does is make it more difficult for a novice to repair.

You have mentioned that a couple of times.  Unless you publish your results it is irrelevant to the originators goals.  And if it took you more than a few hours to figure out it might have met their goals even if you published.  Finally, knowing your proclivities a sophisticated anti-tamper person might strew a few ground chip designs around to distract you from more important and more discretely protected devices.
 

Offline AVGresponding

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Re: Someone in 1988 had a boring job...
« Reply #35 on: October 16, 2022, 08:23:05 am »
I rather doubt the market for garden lights is so fiercely competitive that this has any point whatsoever. All it does in my mind is increase the manufacturing cost by adding another processing step and requiring additional equipment and consumables (grinding wheels, sandpaper, file, whatever they are using).
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Offline PlainName

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Re: Someone in 1988 had a boring job...
« Reply #36 on: October 16, 2022, 09:03:41 am »
Could  be just part of The Process. Maybe they make other stuff which is rather more sensitive to being ripped and their in-house process includes removing markings, just like it might also include "bend through-hole leads at 45 degrees".
 

Offline AVGresponding

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Re: Someone in 1988 had a boring job...
« Reply #37 on: October 16, 2022, 10:01:47 am »
You really think producers of cheap tat like this also make anything high end? Colour me sceptical.
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Offline PlainName

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Re: Someone in 1988 had a boring job...
« Reply #38 on: October 16, 2022, 10:13:48 am »
'Sensitive' doesn't have to equate to 'high-end'. And whoever puts that together is probably a contract house who build for many clients. I have no idea if that is the case, but it's not beyond the realms of possibility - guidelines are blindly followed regardless of appropriateness all over the place.
 

Offline AndyBeez

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Re: Someone in 1988 had a boring job...
« Reply #39 on: October 16, 2022, 03:09:25 pm »
You really think producers of cheap tat like this also make anything high end? Colour me sceptical.
Industrial espionage, certainly not with this tat; but when you guys now know the PCBs seemed hand soldered, maybe the obscuration was to prevent component theft by the poor bastards who were enslaved on the one dollar and a bowl of rice a day assembly line. This solar light retailed for ONE British pound. How much would that inductor alone cost from Digikey?

As for reverse engineering, it's always a cool mind challenge to discover what parts a manufacturer deemed restricted. But figuring out their motivation is less than clear, even when the part turns out to be nothing more than an obsoleted ST microcontroller. Maybe it's the build customer they're out to deceive when they might have to qualify where their stock came from? It would be very tempting to paint or grind an opamp with a 1990s date code, if it were priced 25 years later.
 

Offline AVGresponding

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Re: Someone in 1988 had a boring job...
« Reply #40 on: October 16, 2022, 03:31:00 pm »
You really think producers of cheap tat like this also make anything high end? Colour me sceptical.
Industrial espionage, certainly not with this tat; but when you guys now know the PCBs seemed hand soldered, maybe the obscuration was to prevent component theft by the poor bastards who were enslaved on the one dollar and a bowl of rice a day assembly line. This solar light retailed for ONE British pound. How much would that inductor alone cost from Digikey?

As for reverse engineering, it's always a cool mind challenge to discover what parts a manufacturer deemed restricted. But figuring out their motivation is less than clear, even when the part turns out to be nothing more than an obsoleted ST microcontroller. Maybe it's the build customer they're out to deceive when they might have to qualify where their stock came from? It would be very tempting to paint or grind an opamp with a 1990s date code, if it were priced 25 years later.

That makes a bit more sense.
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Offline james_s

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Re: Someone in 1988 had a boring job...
« Reply #41 on: October 16, 2022, 05:07:18 pm »
You have mentioned that a couple of times.  Unless you publish your results it is irrelevant to the originators goals.  And if it took you more than a few hours to figure out it might have met their goals even if you published.  Finally, knowing your proclivities a sophisticated anti-tamper person might strew a few ground chip designs around to distract you from more important and more discretely protected devices.

I still maintain that it's useless and a complete waste of time, I'm far from the only person who chuckles whenever I open a device and find that the numbers have been ground off the chips. It's a practice I associate with amateurs in China, I've never actually seen it done in anything reputable. It's especially laughable with something trivial like solar garden lights, anyone who can't design the circuit for one of these themselves in a day has no business calling themselves an EE. There are numerous ICs that do the whole thing and the entire circuit can be lifted from the datasheets.

I have seen a clever twist a few times where commodity part numbers were put on custom ROMs in some 70s arcade games, but even then it was obvious from the (published) schematic diagrams that the part was a ROM.
« Last Edit: October 16, 2022, 05:09:26 pm by james_s »
 

Online RJSV

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Re: Someone in 1988 had a boring job...
« Reply #42 on: October 17, 2022, 02:27:05 am »
Haha, LOL:
   Some guys rummaged around, in Barney's parts drawer, got some stray circuit board, put a HEAT -SHRINK tube on one of the connector pins...And threw that sucker straight into the 'Engineers Cage'...where those engineers began examining / discussing possible reasons,...reasons WHY ?
   Three hours later...
 
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Offline pardo-bsso

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Re: Someone in 1988 had a boring job...
« Reply #43 on: October 17, 2022, 01:29:47 pm »
This thing's engineering is epic. The PCB even has grid coordinates silkscreened on it, A B C D 1 2 3 4,.

Nuts.

Actually that was very usual and is extremely helpful when you look at service manuals or schematics, you can quickly map where is each component/subsystem located.
 

Offline PlainName

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Re: Someone in 1988 had a boring job...
« Reply #44 on: October 17, 2022, 02:49:56 pm »
And alternatively, passives numbered from top left to bottom right on the schematic(s), with ICs numbered top left to bottom right on the PCB. Reasoning is that ICs are easy to locate on the schematic and passives relatively easy on the PCB because they'll be next to the same IC they are on the schematic. Of course, the trend to have things connected via labels rather than lines on the schematics mitigates against that, now.
 
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Offline james_s

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Re: Someone in 1988 had a boring job...
« Reply #45 on: October 19, 2022, 01:19:05 am »
This thing's engineering is epic. The PCB even has grid coordinates silkscreened on it, A B C D 1 2 3 4,.

Nuts.

Actually that was very usual and is extremely helpful when you look at service manuals or schematics, you can quickly map where is each component/subsystem located.

Most of the older arcade games had that. It was practically essential when you had a PCB that was 12"x18" or larger.
 

Offline Kasper

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Re: Someone in 1988 had a boring job...
« Reply #46 on: October 19, 2022, 06:32:58 am »
When you forgot to put a 'revision #' on the silkscreen, so you mark a pin as the rev #?

The idea 'insulate the pin from a screw' doesn't work, since there are two pins with identical spacing from the hole. And the screw/washer would contact the solder fillet anyway.

if you look closely you can see that the other nearby pins are connected to the same ground plane as the mounting hole

Could use a non-conductive washer to protect the fillet.

I used to do stuff like this in avionics right out of college.  It was boring but not as bad as you'd think.  I'd tinker, listen to music and chat with coworkers all day.  We'd build 10 to 30 radios at a time and they required a lot of mods and tuning so there was a fair bit of variety.  Some higher ups decided it was better to do lots of mods than to go through recertification required for an updated PCB.

Sometimes I put tubes over pins like this but it was on transistors, we'd rearange the pinout and use the tubes to stop the pins from shorting to eachother.  We'd also put kapton tape on PCB beside a ceramic cap and then solder 3 caps to it.

Our speed and QA failure rate had a small impact on our wage so that added a bit of entertainment as well.
 


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