Brian, I know that you do not want to remove a protective plate such as gold, which will prevent oxidation, such as what you will get with bare silver or copper, which is liable to change over time due to the effects of the oxidation, but you can do fine "tweaking" with solder plate, so long as you do not totally remove it, which it sounds like you are doing.
Another way to "tweak" a circuit would be to thin out the amount of "solder mask" which will change the "dielectric constant" of a trace, and hence the "velocity factor", although that would be a change of a different kind than the "inductance" you are dealing with, and probably a little harder to get optimal results with, and where you would probably use something like acetone or some other solvent as opposed to an eraser. Then again, you could possibly actually get down to bare copper if you really wanted to change inductance by thinning things out, and then give the area a very thin protective spray to prevent oxidation, without affecting the net change in inductance too much, if at all. Respecting cleaning the "card edge connector fingers", which is usually the first thing any Technician will look at: Digital Equipment (DEC) once put out a tech bulletin back in the early 70's stating that anyone caught using an "eraser" on card edge connectors would be fired on the spot, once they found out that that was how their tech support people were "fixing" their malfunctioning equipment in the field, but they additionally followed it up with much better designs on their connectors at the same time, along with thicker plating on their "fingers", which lead to yet another problem in some areas, due to the extra "resistance" of the thicker gold plating. That's why the Military was also freaking out about the amount of gold on connector contacts and fingers back in the early 70's, but for just the opposite reason, the Military wouldn't stand for the extra resistance, or the gold embrittlement when it came to soldering. JaMi * * * * * * ----- Original Message ----- From: "Brian Guralnick" <[EMAIL PROTECTED]> To: "Protel EDA Discussion List" <[EMAIL PROTECTED]> Sent: Friday, November 26, 2004 1:05 PM Subject: Re: [PEDA] Dielectric constant > Read my full reply/description. > > I do know that if you have gold, or silver plating, you will be stripping a > few thousand atoms at a time from the vertical thickness, since, you see > them darkening up the eraser. Also, it seems to get rid of any oxidizing > layers. It's especially great at re-finishing gold-thinger edge card PCBs. > > ________ > Brian G. > > > ----- Original Message ----- > From: "JaMi Smith" <[EMAIL PROTECTED]> > To: "Protel EDA Discussion List" <[EMAIL PROTECTED]> > Sent: Friday, November 26, 2004 3:51 PM > Subject: Re: [PEDA] Dielectric constant > > > > Brad, > > > > By using an eraser, you can do a very fine trim of the thickness of the > > trace, and > > hence a very fine "tweak" of the electrical characteristics, especially if > > you have > > a solder plate / HASL. > > > > JaMi > > > > > > > > ____________________________________________________________ > You are subscribed to the PEDA discussion forum > > To Post messages: > mailto:[EMAIL PROTECTED] > > Unsubscribe and Other Options: > http://techservinc.com/mailman/listinfo/peda_techservinc.com > > Browse or Search Old Archives (2001-2004): > http://www.mail-archive.com/[email protected] > > Browse or Search Current Archives (2004-Current): > http://www.mail-archive.com/[email protected] > ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[EMAIL PROTECTED] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
