List of common bummers

Morten Leikvoll wrote:

Just made a major bummer on a prototype, and I thought first, why do I (and

others) do these errors over and over again.. So maybe its time to collect a

list of common bummers. There should be a checklist for common errors, maybe

even included in the DRC box as plain text! (Hey, Ill post that on suggest!)

 

Here is my recent ones:

 

1. PCB board thickness when using edge connector. In the heat of picking a

stackup for a 10 layer board, the stackup suggestion from the manufacturer

chose their own thickness (tiny number in a tiny box). Neither we, or any of

the other 3 partners involved in the PCB production ever thought that since

there is an edge connector, the thickness is critical.

2. Part verification. There should be a flag on all components called

"verified", that is set to NO on never manufactured parts. Maybe even a text

field for a "verified" attribute. I know very well that is a common problem.

Either pitch is wrong, pads are wrong size, pin numbering is

mirrored/interleaved or wrong somehow. Recently, I managed to mess up the

pinout of a CF socket. Pin numbering should be interleaved, but I managed to

do them sequential. I also managed to mirror the 4 wire pairs on a ethernet

connector.

 

Please submit your own bummers (and don't be ashamed, we all do them)

 

 

 

Good ideas Morten.  I like the idea of Verfied check box.  One thing I

do now if have a verified and unverified library.  I make a part in

unverified and then copy it to verified once it is produced.  However

this process is troublesome and time consuming.  Some other way to mark

a part would be nice.  One method is in the part description.

Another check that could be added to the list:  Silkscreen overlapping

with holes or vias.  Some design are complex and I will miss an overlap

which will ruin the silkscreen.  Maybe there is a way to check for

collisions already, but I haven't look into it.  If there isn't a way,

perhaps a way can be created.

In the CAM system one can build there own jobs and the who, what, where,

when, and how of a design output.  I like this.  Perhaps some sort of

similar system can be built in DRC so that one can set workflows and

levels through the work flows.  For instance, when I am routing a board

I want to know clearances, but I don't care about text or overlaps just

yet.  It would be nice to run a "partial" DRC on just the portion that I

care about.  As the design nears completion I care about the finer details.

Morten Leikvoll wrote:

Just made a major bummer on a prototype, and I thought first, why do I (and

others) do these errors over and over again.. So maybe its time to collect a

list of common bummers. There should be a checklist for common errors, maybe

even included in the DRC box as plain text! (Hey, Ill post that on suggest!)

 

Here is my recent ones:

 

1. PCB board thickness when using edge connector. In the heat of picking a

stackup for a 10 layer board, the stackup suggestion from the manufacturer

chose their own thickness (tiny number in a tiny box). Neither we, or any of

the other 3 partners involved in the PCB production ever thought that since

there is an edge connector, the thickness is critical.

2. Part verification. There should be a flag on all components called

"verified", that is set to NO on never manufactured parts. Maybe even a text

field for a "verified" attribute. I know very well that is a common problem.

Either pitch is wrong, pads are wrong size, pin numbering is

mirrored/interleaved or wrong somehow. Recently, I managed to mess up the

pinout of a CF socket. Pin numbering should be interleaved, but I managed to

do them sequential. I also managed to mirror the 4 wire pairs on a ethernet

connector.

 

Please submit your own bummers (and don't be ashamed, we all do them)

 

Mine was during my first year as an engineer, large super-dense SMT

boards which was quite a feat in the late 80's. I am not a fan of source

termination for various reasons, so my board didn't have any. System

came together, weird reflections on an internal multi-channel RF bus.

"Why are there no terminators on your board?" ... "I thought you had

them on yours" ... "No, I was under the assumption they were on yours"

... our boss almost exploded.

Luckily we managed the situation by changing the LC filter values. Whew.

--

Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.

Use another domain or send PM.

On 5/6/2010 12:59 AM, Morten Leikvoll wrote:

Just made a major bummer on a prototype, and I thought first, why do I (and

others) do these errors over and over again.. So maybe its time to collect a

list of common bummers. There should be a checklist for common errors, maybe

even included in the DRC box as plain text! (Hey, Ill post that on suggest!)

 

Here is my recent ones:

 

1. PCB board thickness when using edge connector. In the heat of picking a

stackup for a 10 layer board, the stackup suggestion from the manufacturer

chose their own thickness (tiny number in a tiny box). Neither we, or any of

the other 3 partners involved in the PCB production ever thought that since

there is an edge connector, the thickness is critical.

2. Part verification. There should be a flag on all components called

"verified", that is set to NO on never manufactured parts. Maybe even a text

field for a "verified" attribute. I know very well that is a common problem.

Either pitch is wrong, pads are wrong size, pin numbering is

mirrored/interleaved or wrong somehow. Recently, I managed to mess up the

pinout of a CF socket. Pin numbering should be interleaved, but I managed to

do them sequential. I also managed to mirror the 4 wire pairs on a ethernet

connector.

 

Please submit your own bummers (and don't be ashamed, we all do them)

 

 

Proportional Text in board layers.

Wrong hole size for hi power thru hole component leads.

"Morten Leikvoll" <mleikvol@yahoo.nospam> wrote in message

news:hrtsti$7vf$1@cheetah.cadsoft.de...

Just made a major bummer on a prototype, and I thought first, why do I

(and others) do these errors over and over again.. So maybe its time to

collect a list of common bummers. There should be a checklist for common

errors, maybe even included in the DRC box as plain text! (Hey, Ill post

that on suggest!)

 

Here is my recent ones:

 

1. PCB board thickness when using edge connector. In the heat of picking a

stackup for a 10 layer board, the stackup suggestion from the manufacturer

chose their own thickness (tiny number in a tiny box). Neither we, or any

of the other 3 partners involved in the PCB production ever thought that

since there is an edge connector, the thickness is critical.

2. Part verification. There should be a flag on all components called

"verified", that is set to NO on never manufactured parts. Maybe even a

text field for a "verified" attribute. I know very well that is a common

problem. Either pitch is wrong, pads are wrong size, pin numbering is

mirrored/interleaved or wrong somehow. Recently, I managed to mess up the

pinout of a CF socket. Pin numbering should be interleaved, but I managed

to do them sequential. I also managed to mirror the 4 wire pairs on a

ethernet connector.

 

Please submit your own bummers (and don't be ashamed, we all do them)

Hi,

what about an interface in the DRC-check to an user-defineable ULP?

With this feature, a user would be able to extend the DRC check with

functionality at his/hers

own discretion.

Carsten

On Thu, 6 May 2010, Gary Gofstein wrote to us saying :

On 5/6/2010 12:59 AM, Morten Leikvoll wrote:

 

Please submit your own bummers (and don't be ashamed, we all do them)

 

Wrong hole size for hi power thru hole component leads.

Using an SOIC18 package for an SOIC18W part

Although the second time I did this it was because I managed to order

the wrong parts...

--

Rob Pearce                       http://www.bdt-home.demon.co.uk

The contents of this | Windows NT crashed.

message are purely   | I am the Blue Screen of Death.

my opinion. Don't    | No one hears your screams.

believe a word.      |

Robert Pearce wrote:

On Thu, 6 May 2010, Gary Gofstein wrote to us saying :

On 5/6/2010 12:59 AM, Morten Leikvoll wrote:

 

Please submit your own bummers (and don't be ashamed, we all do them)

 

Wrong hole size for hi power thru hole component leads.

 

Using an SOIC18 package for an SOIC18W part

Although the second time I did this it was because I managed to order

the wrong parts...

It could have been worse, here's Henry Ford's bummer:

http://www.hfmgv.org/exhibits/showroom/1896/receipt.html

Quote "Ironically, in his enthusiasm Ford neglected to notice that the

vehicle was too wide for the doors to his Bagley Avenue shop, ..."

--

Regards, Joerg

http://www.analogconsultants.com/