10-15-2010, 01:18 PM
I wonder if the reason why the mica caps in the pushbutton section go bad is because, unlike most mica caps of the period, these usually only have wax insulation instead of the hard plastic used on most mica caps?
The originals were usually 390 pF; I use 370 pF dipped micas as replacements, which work quite well. 350 pF would also be OK.
Whatever you do, don't use ceramic discs to replace the two caps in the pushbutton assembly unless they are NP0 (temperature compensating) caps! Normal ceramics will let the preset stations drift after the radio warms up (don't ask how I know this). Micas will hold the adjustments steady.
The originals were usually 390 pF; I use 370 pF dipped micas as replacements, which work quite well. 350 pF would also be OK.
Whatever you do, don't use ceramic discs to replace the two caps in the pushbutton assembly unless they are NP0 (temperature compensating) caps! Normal ceramics will let the preset stations drift after the radio warms up (don't ask how I know this). Micas will hold the adjustments steady.
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Ron Ramirez
Ferdinand IN
