[R-390] 4 kc filter

[Norman Ryan]

Hello, Les and crew,

True enough.  But I wonder why that is.

Is it disintegrating plastic foam gumming up the works or causing the
resonator to touch the shell?

While I'm here, anyone know the enameled wire size on the bobbins?  How
many feet of wire for 50 Ohms DC resistance?  I've got a couple of duds
I'd like to try and revive some time.

Other than resoldering a broken lead inside, has anyone successfully
revived one of these either by rewinding the bobbin or replacing plastic
foam?

73 de Norman KG4SWM


Llgpt@aol.com wrote:
> They might be good "now', but the 4 kc filter is/was the most used filter on
> the R-390A. They will only vibrate a certain number of times before they go
> kaput! And, that time has approached judging from the failure rates being
> reported now.
> 
> Les