[TenTec] Tantalum Capacitor Pointers?

[george fritkin]

Depending on the application you may be wasting your money.  Usually the POSITIVE lead is LONGER on a Tantalum.  Since their loss is lower than an electrolytic it should be cooler.  Getting hot does denote a problem
George, W6GF

--- On Mon, 6/27/11, Steve Berg <wa9jml at tbc.net> wrote:

From: Steve Berg <wa9jml at tbc.net>
Subject: Re: [TenTec] Tantalum Capacitor Pointers?
To: tentec at contesting.com
Date: Monday, June 27, 2011, 8:40 AM


I have been gradually working my way through my first Argonaut II.  I 
have had troubles with the inverter circuit that drives the display back 
light.  I replaced the two electrolytics in that circuit with tantalums 
of the same ratings, and while it works, the one 30 MFD power line 
bypass cap runs hot, and the display back light is dim.  Since I have 
the topside switch board out to replace the back light switch, I want to 
replace the electrolytics on that board, too.  It has been some years 
since I had the chance to work with tantalum capacitors, and I recall 
that the lead by the heavy black line on the package is the negative 
lead.  That is how I installed them in the inverter circuit.  Yet the 
one cap runs hot, the other one does not.  Do I have a bad capacitor, or 
is there some other problem here that I am not aware of?  I figured that 
tantalums would be much better capacitors than electrolytics, which is 
why I have been trying them.  Am I missing something here?  Can someone 
give me some pointers?

Thanks!

Steve WA9JML
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