[Premium-Rx] Replacing old tantalums?

[GandalfG8 at aol.com]

In a message dated 14/04/2009 00:39:53 GMT Daylight Time,  
ToddRoberts2001 at aol.com writes:

Glad  to hear they can be replaced with common 100uF/25V  electrolytics. 
Those are dirt  cheap nowadays.Just curious what types  are in there now 
that 
need replacing?  Radial lead or axial lead?  100uF/25V seems to be an 
unusually 
large size for a  dry tantalum,  they usually go up to 47 or 68uF in that 
voltage range. 47uF/25V  dry  tantalums seem to go for around $4-$5 each 
brand 
new. Someone could  parallel  2 of those small ones for 94uF/25V for less 
than $10 for  each replacement. You  must be looking at wet tantalums in 
the 
Mouser  catalog?



----------------------
Wet tantalums of that capacity and rating are certainly a different ball  
game.
Looking at Farnell again I could pay $100 each for those, plus a delay and  
surcharge to have them sourced from the US.
These are Vishay axial leaded parts rated for aerospace applications.
 
Although I haven't got the schematic to hand the chances are high that  
tantalum caps of this type and size are part of a power supply section, and 
with  tantalum originally being specified more for environmental reasons than  
electrical necessity.
Even if HP hadn't suggested it I'd have been very surprised if  replacement 
with a normal electrolytic wasn't adequate.
 
regards
 
Nigel
GM8PZR