On a flying head tester, typically, nets are first checked for opens.
This is done one net at a time, with the probes touching the ending 
points and/or intermediary points within a given net.

After testing for opens, the next step is to check for shorts. One 
probe is placed on a test point from one net while the other probes 
touch points on adjacent nets to verify that no shorts exist. 

When testing for both opens and shorts, boards are "scanned" left to,
with the software optimizing the movement and travel of the probes to 
minimize test time.

Bed of nails testing checks for opens and shorts while touching all 
test points at the same time.

Luis Rivera
CompuRoute, Inc.
Dallas, TX
[log in to unmask]
(214) 340-0543

> Date: Fri, 13 Dec 1996 10:11:00 -0500 (EST)
> From: Jim Marsico 516-595-5879 <[log in to unmask]>
> Subject: Re: test: FLYING PROBE VS. HARD TOOLING
> To: [log in to unmask]
> 
> Is it true that with flying probe testing that you test only 
> one net at a time? 
>
> If so, how do you know if you have a short between nets? 
> 
> Doesn't bed-of-nails testing also test for shorts between nets?
> 
> Jim Marsico
> 
 

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