Homebrew PCBs

Hi all,

Part of my motivation for seeking advice regarding ESD practices is the 
failure of a circuit I constructed a year or two ago. It had a handful 
of 74ACT- something-or-other latches on it. The PCB functioned as 
expected for a good while. Following some interfacing with other PCB's 
and the associated handling, connecting, disconnecting, etc., the latch 
PCB failed. I eventually determined that two of the latches were bad, 
replaced all of them and was back in business.

Discussions with the engineer who designed the circuit revealed that I 
was not the first to go down this path. The engineer, involved in this 
type of work professionally and well experienced, thought my and other 
failures to be ESD related. I take that advice as his best guess based 
on his experience -- I'm pretty sure he never examined one of the failed 
latches with an electron microscope to confirm ESD issues. That incident 
made me somewhat more ESD conscious than previously and hence my 
questions of this group.

Another aspect to consider is the time and test equipment needed to 
trouble shoot a non-working PCB, some of which can be pretty complex.  
I'd rather not take the time to trouble shoot and I may not have the 
signal generator, scope, logic analyzer, or whatever to effectively find 
the problem. Taking a modicum of ESD precautions seems a reasonable 
tradeoff, especially if I already have the ESD workbench mat and wrist 
strap.

At any rate, this is (for me) an interesting thread from the perspective 
that I am not a professional PCB design/build guy, nor am I particularly 
well experienced in at-home construction techniques. I'm learning. I 
appreciate the advice and thoughts offered.

Steve K8JQ

On 12/24/2011 12:50 PM, AlienRelics wrote:
> Amend that to unvarnished wood floors. ;') Asphalt tiles or ceramic tiles are good insulators.
>
> I do agree with what you are saying.
>
> To paraphrase another poster, I've never been hit by lightning but I still won't go swimming or kite flying during a storm. On the other hand, I've been out backpacking and I don't bring lightning rods or a Faraday cage with me.
>
> Steve Greenfield AE7HD
>
> --- InHomebrew_PCBs@yahoogroups.com, "Boman33"<boman33@...>  wrote:
>> I am running production lines and supervising two engineering labs and the
>> ESD problems exist.  What you and others fail to take into account is the
>> environment.
>>
>> If someone is in South Florida without air-conditioning= high humidity, tile
>> floors, and walking barefoot, there is never going to be a problem.  Then
>> someone up north in the winter with low humidity, carpeted floors, and
>> rubber soled shoes, there will be lots of problems.
>>
>>
>>
>> Hobbyists need to be realistic and practical without overdoing it in either
>> direction.
>>
>> Bertho
>>
>>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

-- 
Read The Patriot Post    Vertitas vos Liberabit
http://patriotpost.us/subscription/