|[AMRadio] Old Mica Caps in OLD VFOs|
knjhanlon at msn.com
Thu Oct 25 14:28:01 EDT 2012
In my experience, I have not had a problem with old mica caps in old vfos. I have two Johnson 122 vfos that show a bit of thermal drift, but no other problems. I have two Heath VF1a that are more stable than the Johnson 122s. I have two Knight VFOs that are also more stable than the Johnsons. I have a DX-100 and a Valiant. The DX-100 is quite stable, while the Valiant shows the same kind of slow, thermal drift that the Johnson VFOs do. I also have a Millen 90711 vfo, a Harvey Wells Bandmaster vfo, a Geloso vfo, a Heath HG-10, tow Hallicrafters HT-18s, and vfos in a Knight T-150A, Elmac A-54, AF-67 and AF-68, Lysco 600, Heath TX-1, and three ptos from the T195 transmitter. None of them show any obvious capacitor problems.
This is not to say that an individual unit may not have a problem, but I certainly would not advise wholesale replacement of the mica caps in an old vfo before I tried it out.
Jim Hanlon, W8KGI
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