Re: Current through the soldering iron tip

Craig Zeni
 

Electrostatic discharge...

Craig Zeni
Cary, NC
Despatched from my infernal Android

On Tue, Jun 11, 2019, 21:11 Greg Smith <gcscls@...> wrote:
Denny
I checked and I have a WES 51.  It is marked ESD Safe on the front of the case.  Do you know what “ESD Safe” means?
Greg
 
From: Denny Anspach
Sent: Tuesday, June 11, 2019 11:09 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Current through the soldering iron tip
 
I am the person who alerted Larry to this issue, an issue notably prevalent in non-grounded irons, especially those with ceramic insulation.  It becomes a potential lethal problem when soldering fine electronics (read: DCC decoders). An authoritative standard industry text book on electronic soldering strongly warns against using ungrounded irons on such circuitry.
 
This came to my attention when I sequentially fried the audio circuitry of three new sound decoders, and neither I nor the manufacturer had a clue as to what was happening (although -in frustration- not without some mutual polite finger pointing in the process).  A model railroad  EE engineer colleague (whose day job is industrial trouble shooting chip problems) -by elimination- discovered the problem:  my faithful super-reliable non-grounded  red Weller WLC100 soldering station was leaking a measured 28V through the hot iron (the cold iron had no leakage).  I banished this iron, and a bunch of other ungrounded irons immediately from all electronic work, switched to a better grounded Weller station specifically qualified for electronic work  ("ESD SAFE") and all problems disappeared like the snow in the midday sun.
 
I have been installing decoders for almost 20 years, so this internal breakdown occurred somewhere along the way, or the decoder circuitry became more vulnerable.  
 
The WLC100  is a very popular work horse model, still very much on the market, and notably has not been sold by Weller as safe for electronics.
 
Denny
 
 
 
Denny S. Anspach MD
Okoboji, IA
 
 
 

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