[R-390] R-390 (non-A) Sudden and New Issue

[Barry]

The line input filter is a small, sealed metal box just in front of the power connection in the back of the radio.  I rebuilt mine due to a burnout condition which was not a "fun" project.

73,
Barry - N4BUQ

> Hi Jordan,
> 
> This restoration was performed by someone other than me.  Which filter are
> you referring to on the schematic?
> 
> Thank you
> -Alex
> 
> On Thu, Feb 26, 2026 at 3:56 PM Jordan Arndt <Outposter30 at shaw.ca> wrote:
> 
>> Out of curiosity, was the AC input filter rebuilt or replaced when it was
>> restored..?
>>
>> 73...Jordan VE6ZT
>>
>>
>>
>> ----- Original Message -----
>> From: "Alex Hopper" <ahopper0216 at gmail.com>
>> To: "R-390 Mailing List" <r-390 at mailman.qth.net>
>> Sent: Thursday, February 26, 2026 11:46 AM
>> Subject: [R-390] R-390 (non-A) Sudden and New Issue
>>
>>
>> > Hi Folks,
>> >
>> > I have an R-390/URR (non-A model) that was restored by someone last year
>> -
>> > the individual who restored this set is quite competent and did good
>> work.
>> >
>> > Over the last few days I have noticed 'popping' and 'cracking' coming
>> from
>> > the set.  Sounds like what you would hear if there was a lightning strike
>> > nearby, or if there was an internal component that aws arcing.
>> >
>> > As a result the radio does not receive on any bands at the moment.  I
>> took
>> > it out of its cabinet and checked/replugged all the connectors between
>> > modules.  I fired it up and it worked perfectly normal.  I turned it off,
>> > put it back in the cabinet and...same issue!  I removed it again and the
>> > issue persists.
>> >
>> > I don't even know where to start with this, and I am upset that my
>> beloved
>> > R-390 seems to be dead in the water.
>> >
>> > any suggestions or thoughts?
>> >
>> > Thanks,
>> > -Alex
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