Hi B.R.

This sounds like either of a couple of problems may exist.

1. There may be an improper cleaning prior to soldermasking, leaving a
conductive residue on the board, resulting in what is Known as Hi "Z" shorts
or;

2. Improper coverage of the soldermask allowing flux to be entrained,
especially if there is close proximity of pad to trace.

3. A third option may be small particulates of copper remaining from the
circuit etch process.

Lots of luck in solving the problem,

Les Connally

[log in to unmask] 

------------------
Original text

From: "B.R.SHASHIRAJ" <[log in to unmask]>, on 7/24/97 6:28 PM:
Hello Technetters,
        Can some one out their throw some light on below mentioned problem
,probable causes and solutions.
       1. this defect noticed on 1.6mm double sided board, smobc,hal finish.
       2. after assembly and while testing at elevated temperature noticed 
 shorts during test cycle on the solder side between connector pads and trace 
running thro.
       3.unable to figure out ,this shorts appear of very little dimension and
are very small compared to pad /trace.
     
      can some one figure what this cud be and why
  THANKS.

BYE.
                  

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