[R-390] Mechanical Filter Failure?

Bob Camp ham at cq.nu
Tue Dec 18 10:14:54 EST 2007


Hi

Before you go to crazy - sling a 10K ohm resistor between input and  
output directly on the filter. That should give you a quick  
verification that the signal path does not have any "gremlins" in it.

Bob


On Dec 17, 2007, at 11:09 PM, Jon Schlegel wrote:

> Hi guys and gals,
>
> I'm working on bringing up an R-390A and have no response through  
> the 2 kHz mechanical filter.  It's my understanding that the usual  
> failure mode for these is an open coil on the input or output yet I  
> measure 40 - 50 ohms DC on both input and output of the 2 kHz  
> filter.  Checked the rest of the signal path around the filter  
> especially the rotary switch and all checks ok.  Is there anything  
> else I should look at before thinking about finding a replacement?
>
> Regards,
> Jon, WA3MVM
>
>
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