Author Topic: Worst PCB Ever?  (Read 15094 times)

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Offline funkyant

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Worst PCB Ever?
« on: June 01, 2017, 10:52:18 am »
This was a post on Reddit, but was just too good not to share here:

https://www.reddit.com/r/electronics/comments/6efm66/worst_pcb_ever/



:-DD  :palm:


Quote
I used to work as a lab assistant for a local state university and have seen some amazing and some crappy projects come though.

The image above was supposed to be a "function generator" for a 400 level final project!  One of the FOUR STUDENTS assigned to this train-wreck came over to me and asked for help "diagnosing" what was wrong with their circuit board.  Not only did they not fundamentally understand that circuit traces could not be overlapped, but they had been trying to repair the trace they broke by using solder as wire. 

Normally, I am an extremely sympathetic person when it comes to situations like this, but they waited until the last minute, did not ask any questions beforehand, did not ask to have their circuit checked before they ordered it, and did not attend any of the many after-class PCB/soldering meetups that I often arranged.  It is the worst circuit I have seen to date, and figured I would finally share it with all of you.
« Last Edit: June 01, 2017, 11:15:40 am by funkyant »
 
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Online grumpydoc

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Re: Worst PCB Ever?
« Reply #1 on: June 01, 2017, 11:01:48 am »
Wow
 

Offline P90

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Re: Worst PCB Ever?
« Reply #2 on: June 01, 2017, 11:08:47 am »
project for modern art class?  LOL
 
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Offline Zero999

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Re: Worst PCB Ever?
« Reply #3 on: June 01, 2017, 11:10:20 am »
Did they fail or have time to redo it?

It looks like it was made in house, are the holes through plated? If so, how was it done?

I'm surprised the university got boards made in house, wouldn't it be cheaper to get them done externally?
 

Online JPortici

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Re: Worst PCB Ever?
« Reply #4 on: June 01, 2017, 11:12:28 am »
was that a fritzing job?
 

Offline funkyant

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Re: Worst PCB Ever?
« Reply #5 on: June 01, 2017, 11:17:34 am »
Did they fail or have time to redo it?

I'd make a pretty solid guess that even if they respun it, they still would have failed  :-DD
 

Offline X

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Re: Worst PCB Ever?
« Reply #6 on: June 01, 2017, 11:22:33 am »
Did they fail or have time to redo it?

It looks like it was made in house, are the holes through plated? If so, how was it done?

I'm surprised the university got boards made in house, wouldn't it be cheaper to get them done externally?
Some unis actually have their own small-scale silicon fab. Not likely to put Intel out of business, but when research-grade results are required, you'll be surprised at what length unis will go through to ensure they can control the process, which is very handy when you want to keep the number of independent variables under control.
« Last Edit: June 01, 2017, 11:25:23 am by X »
 

Offline CJay

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Re: Worst PCB Ever?
« Reply #7 on: June 01, 2017, 11:30:56 am »
Did they fail or have time to redo it?

I'd make a pretty solid guess that even if they respun it, they still would have failed  :-DD

Fourth year project with four students working as a team, I bloody hope they failed if that was the level of their subject knowledge.
 

Offline funkyant

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Re: Worst PCB Ever?
« Reply #8 on: June 01, 2017, 11:47:26 am »
Did they fail or have time to redo it?

I'd make a pretty solid guess that even if they respun it, they still would have failed  :-DD

Fourth year project with four students working as a team, I bloody hope they failed if that was the level of their subject knowledge.

It's the:

Quote
they not fundamentally understand that circuit traces could not be overlapped

that's really the kicker! hahahahaha
 

Offline Jeroen3

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Re: Worst PCB Ever?
« Reply #9 on: June 01, 2017, 11:50:59 am »
When art students try electronics.
 

Offline amyk

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Re: Worst PCB Ever?
« Reply #10 on: June 01, 2017, 11:54:48 am »
:o part of me wants to think that this was done as a joke. Then again, given some people I've met... :-\
 

Offline tatus1969

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Re: Worst PCB Ever?
« Reply #11 on: June 01, 2017, 01:01:32 pm »
hard for me to believe this is real. i have to show this to my 14yr old son :palm:
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Offline Ash

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Re: Worst PCB Ever?
« Reply #12 on: June 01, 2017, 01:28:28 pm »
But it worked in SPICE.....  :wtf:  :-DD  :-//

 

Offline igendel

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Re: Worst PCB Ever?
« Reply #13 on: June 01, 2017, 01:39:10 pm »
What's wrong with crossing traces? Electrons that come from the left continue to the right because of momentum, electrons from the top continue to the bottom... it's simple physics people!  :-DD
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Online Cerebus

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Re: Worst PCB Ever?
« Reply #14 on: June 01, 2017, 01:40:26 pm »
ot boards made in house, wouldn't it be cheaper to get them done externally?

When I was at university (a relatively small one with ~3500 undergraduates) the university had about 4 student machine shops (excluding the specialist ones for metallurgy and materials science) and two prototype scale PCB shops. How do you expect people to learn if they don't get hands-on experience? If you don't, you end up with people who design things that can't be efficiently manufactured, or even can't be manufactured at all.

If you've got the size to have frequent need of some facility it's often cheaper to have it in house; after all, you're not paying someone's profit. Let alone the usefulness of having experienced staff on hand whose job it is to help you get the best, cheapest job done, not the most profitable or easiest to sell. Even if the economic benefits are marginal or even slightly negative, the convenience, access to processes for teaching and access to experienced technicians can make up for the economic angle with those intangible benefits.

Aside from teaching related facilities as above, the university also had one main and two satellite professional print rooms as it just made commercial sense to have that much printing capacity. Heck, even the student union had its own print room, that kept an ageing Rotaprint 30/90 in daily use.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline Dielectric

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Re: Worst PCB Ever?
« Reply #15 on: June 01, 2017, 01:51:52 pm »
Just  checking in to make sure it wasn't one of my boards.   :-DD
 

Offline EEVblog

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Re: Worst PCB Ever?
« Reply #16 on: June 01, 2017, 01:54:18 pm »
 :clap:
 

Offline mdszy

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Re: Worst PCB Ever?
« Reply #17 on: June 01, 2017, 01:58:56 pm »
I need to hang a picture of this up in my lab, that way every time one of my own boards fails to develop/etch properly, I can look at this and be thankful I didn't make something like this!
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Offline CJay

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Re: Worst PCB Ever?
« Reply #18 on: June 01, 2017, 02:09:21 pm »
What's wrong with crossing traces? Electrons that come from the left continue to the right because of momentum, electrons from the top continue to the bottom... it's simple physics people!  :-DD

At certain frequencies that... No.

Just no  :-DD :-DD
 

Online GreggD

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Re: Worst PCB Ever?
« Reply #19 on: June 01, 2017, 02:11:28 pm »
I have a hard time believing this but if true then not just the students but the school should find something else to do. Hope there are no student loans to be repaid.
I want to see the other side of the pcb.
 

Offline 691175002

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Re: Worst PCB Ever?
« Reply #20 on: June 01, 2017, 02:13:14 pm »
I saw a lot of this kind of thing when I was at university.  If you aren't interested enough in the subject to do projects on your own time you just never connect classroom knowledge to the real world.

Its more prevalent (but less obviously hilarious) in computer science.  If you ask a graduating class to produce a simple application 80% of them will start by implementing a linked list from scratch in C.
 

Offline Zbig

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Re: Worst PCB Ever?
« Reply #21 on: June 01, 2017, 03:02:49 pm »
I saw a lot of this kind of thing when I was at university.  If you aren't interested enough in the subject to do projects on your own time you just never connect classroom knowledge to the real world.

Its more prevalent (but less obviously hilarious) in computer science.  If you ask a graduating class to produce a simple application 80% of them will start by implementing a linked list from scratch in C.

No. There's no sensible explanation for this other than them being dumb as a bag of hammers. I knew this thing wouldn't make any kind of sense when I was 10. And I'm not really that smart, either.
 

Online NANDBlog

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Re: Worst PCB Ever?
« Reply #22 on: June 01, 2017, 03:13:09 pm »
Not even close. The worst PCB I saw was some programing board for some old Motorola microcontroller. Obviously it was autorouted. And it had a lot of logic chip on it for the wierd timing programming requirements for the MCU. It had a bunch of NC pins.
...
...
...
Every NC pin was connected together by the autorouter.
And of course you dont spin the board again, you solve this with the scalpel. And if you fixed the wrong track, you fix your fix with a bodge wire.
 
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Offline mdszy

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Re: Worst PCB Ever?
« Reply #23 on: June 01, 2017, 03:15:20 pm »
Not even close. The worst PCB I saw was some programing board for some old Motorola microcontroller. Obviously it was autorouted. And it had a lot of logic chip on it for the wierd timing programming requirements for the MCU. It had a bunch of NC pins.
...
...
...
Every NC pin was connected together by the autorouter.
And of course you dont spin the board again, you solve this with the scalpel. And if you fixed the wrong track, you fix your fix with a bodge wire.

Pardon my own idiocy... But what's the issue with NC pins getting connected together? If they're not internally connected to anything, what does it matter how they're routed?
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Offline Zbig

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Re: Worst PCB Ever?
« Reply #24 on: June 01, 2017, 03:19:48 pm »
Pardon my own idiocy... But what's the issue with NC pins getting connected together? If they're not internally connected to anything, what does it matter how they're routed?

"Don't connect" often really means "don't connect" and not "don't care where you connect this as it's floating anyway". It's often some factory test connection or such.
 
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