Invariably hand rework and maintenance is done at a remote location form
design and assembly
without the extravagant EDA  tools mentioned below. Repair and mod
instruction  are indicated in
text referring to the replacement of components by reference designator. The
finding of  the said
components can be very difficult and time consuming on assembled troublesome
used boards. Engineers
usually follow a functional block on a Schematic, and would not use
reference designators until referring to
components so the sequence is irrelevant. I sequence reference designators
right reading left to right and top corner to
bottom corner and component side to solder side on the board. Finding
components, even if some of the silkscreen is gone is very easy.

Dave Sharples.


----- Original Message -----
From: Tim Mullin <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 21, 1999 7:25 PM
Subject: Re: [DC] component numbering


> If the reference designators are controlled from the schematic a common
> practice especially when there are many sheets is to assign a range of
> numbers for each sheet. For example on sheet 1 resistors will be assigned
a
> range from R1-99 on sheet 2 R200-299, and so on. This makes it easier to
> locate a component when having to shuffle through many schematic sheets
> because the page number is included in the naming of the reference
> designator. With the cross-probing capabilities of most EDA software today
> it is equally as easy if not easier to locate a component either on a
> schematic or a board regardless of where it is or how it was named.
>
> Best Regards,
>
> Tim Mullin - Regional Director
> INCASES North America, Inc.
> Tel: 253-853-3860  * Fax: 253-853-3861
> Email: [log in to unmask]  *  http://www.incases-us.com
>
> > -----Original Message-----
> > From: Hope Lariosa [SMTP:[log in to unmask]]
> > Sent: Wednesday, October 20, 1999 9:09 AM
> > To:   [log in to unmask]
> > Subject:      [DC] component numbering
> >
> > Is there a 'standard' on how to number components?
> >
> > I'm referring to the way reference designators for components are
placed.
> > If people (engineer, designer, assembler, technician) want to see a
Right,
> > Down method, would that apply to the schematic or the board?  If there
is
> > no stanrdard, I'm sure it all boils down to whatever the people involved
> > agree upon.
> >
> > I was wondering what the popular concensus is...anyone?