On 15 Dec 99 at 9:45, [log in to unmask] wrote:
> Hi All
> Is there a document that addresses the number of jumper wires that
> can be used on an assembly that are not a part of the original
> design. You know the kind that are put on to solve "open" problems.
> Geeeesh!
>
> Susan Mansilla
Hi Susan,
I posted this earlier on this list on a similar
question. I don't know which of the standards I mentioned are
outdated now (at least MIL-STD-275 - replaced by IPC-D-275 - replaced
by IPC-222x, but this one covers no jumper wires) and I don't know
which standards for the below mentioned "lower" class were used for
the numbers of allowed jumper wires. Some other responses on your
question mention MIL-C-28809, like I did. As Kelly M. Schriver wrote,
it is outdated with (as far we know) no direct replacement. The
wonderful MIL-IPC crossreference from Eric Kalgren mentiones a
MIL-C-28809B, related to IPC-CM770D.
** quoted message **
Date sent: Sat, 9 Oct 1999 03:14:42 +0200
Subject: Re: [TN] Maximum jumper wires allowed...
A customer of mine who manufactures mostly class 2 or 3 products has
(or had) the following procedure:
They define two own classes for PWBs and assemblies. The
"lower" class refers to in-house standards, IEC359 and DIN IEC 326,
the "higher" to MIL-P-46843, -P-55110, -STD-275, -STD-454, and
DOD-STD-2000-1 to -4.
The copy of the jumper wire procedure itself is from 1991, and I
assume they have meanwhile these definitions updated to IPC-222x and
other newer standards.
The "lower" class has the following rules:
a) max numbers of ALL repairs, added components, jumper wires etc. PCB
size in cm^2 number < 100: 5 100-300: 10 300-600: 15 > 600:
20
b) jumper wires and added components
< 100: 3
100-300: 6
300-600: 9
> 600: 12
The "higher" class allows no repairs.
For repair they refer to IPC-R-700 and MIL-C-28809, but mostly to
other in-house procedures.
*** End of quoted message ***
Susan, if you reply me offline an tell me which company you are with,
then I can try to ask my customer whether he would be willing to
share the latest revision of his procedure. This should refer to the
latest and valid MIL/IEC/IPC/whatever standards.
Hope this helps.
Regards
Matthias Mansfeld
-----------------------------------------------
Matthias Mansfeld Elektronik
* Leiterplattenlayout, Bestueckung
Am Langhoelzl 11, 85540 Haar; Tel.: 089/4620 093-7, Fax: -8
Internet: http://www.mansfeld-elektronik.de
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