[R-390] Old style Mica Capacitors

[2002tii]

Al wrote:

>I wonder if "NOS" ones go bad at the same rate as ones in service? 
>Having problems with some in R-388's & a few others nowadays.  The 
>100 mmf's in the AGC ckt in particular.  I've been using dipped 
>micas as replacements, they're getting pricey.

Much faster.  The failure mechanism is moisture, and (i) radios are 
generally stored under less humid conditions than parts and (ii) the 
warmth of operating radios tends to keep working capacitors dried 
out.  I have had very poor results with NOS micas from a variety of 
sources that were made before 2000, so I don't buy them anymore.  The 
cost of new caps is nothing compared to the aggravation of having to 
go back in and replace one for a second time.

Best regards,

Don