[R-390] R-390A Filters

[KA9EGW]

I am surprised nobody has tooled up an aftermarket crystal, ceramic or 
mechanical filter [especially 4K as that seems to be the most 
susceptible to end-of-life failure] as has been done for the power 
supply caps and some other unobtanium parts...if I had the time I would 
do it, but with a family member in termina decline I don't.

And whatever happened to Tim Curry's replacement filters?

Are the I/O Z's on current manufacture filters compatible?

73, Brian KA9EGW


On 2/15/2013 3:40 PM, quartz55 wrote:
> I have my 2K and 4K filters removed from the IF.
>
> The 4K appears dead in the IF.  Input and output windings show 51 ohms, to ground the output measures 34Meg, the input measures 370Meg.
>
> 2K in the IF appears to have high loss compared to 8 and 16K filters.  Input and output windings show 53 ohms.  To ground output measures infinity.  Input measures 5.3Meg/1Meg depending on which way I use the leads.
>
> 82pf caps appear good.
>
> Any recommendations for taking them apart?  I've read the articles and the sites with pictures on removing the ends, but I'm still a bit confused about when heating them, how do I keep them from blowing apart with the build up of heat?  I see a nubbin on one end of the filters, right in the center, output end, does that cover a hole?  Or should I just drill a hole in one end before heating them?  They appear to be the later filters, buff colored so there's no connection of the input and output ends.
>
> http://i251.photobucket.com/albums/gg287/DogTi/R390A/filters_zpsb692cc43.jpg
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