Bill,
I can't say that I saw that exact condition but I do recall some error
for the same or similar conditions. Back years ago with P98 I was using the
same pad configuration where we wanted an unplated hole with only a pad on the
top/bottom side. So I had defined the pad as top layer and it was drilled with
an unplated hole. That had worked just fine in P98, not a problem across a
number of boards. However in P99SE, it didn't work and I can't remember the
precise failure. It was something like the pad being dropped from the Gerbers
on the layer where it should have been or possibly a polygon flowed right over
it. Something as equally devastating as the problem you just found. Possibly it
was a polygon on the opposite side not being cleared around the drilled hole
and thus very very similar to your problem.
The conclusion at that time was just to never, never, never, use a
single layer pad with a drilled hole.
Sincerely,
Brad Velander
Senior PCB Designer
Northern Airborne Technology
#14 - 1925 Kirschner Road,
Kelowna, BC, V1Y 4N7.
tel (250) 763-2329 ext. 225
fax (250) 762-3374
-----Original Message-----
From: Brooks,Bill [mailto:[EMAIL PROTECTED]
Sent: Friday, October 21, 2005 9:20 AM
To: 'Protel EDA Discussion List'
Subject: [PEDA] Strange feature.. DRC misses an error condition.
I found a strange condition by accident today that DRC fails to detect.
We had a part mis-defined with a PAD that was a 'toplayer' pad (not a
'multilayer pad') that had a drill hole defined in it... not on purpose, but
by accident.
Now DRC did not pick up any shorts with planes or traces running under this
pad but if drilled and plated through in the actual board it would have
shorted to the internal layers and any tracks running under it.
This happened because somehow we had an unusual condition that the DRC seems
to not check for I guess... not seeing any errors on DRC I assumed the board
was good. The error was caught by our board manufacturer thank goodness and
we corrected the condition.
Has anyone ever run across this before?
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com
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