[R-390] R390 Band Switch Alignment

[Dan Merz]

Roger/others,  I'm getting nearer to doing what you're suggesting and
pulling the rf chassis.  I started listening on 40 meters to see what I
could get out of the 390.  At first,  not even the calibrator signal was
audible on the 7 Mhz range but I got it to come in weakly by turning the Mhz
knob a bit about the detent point.  I put some deoxit on the tube pins,
1st/2nd mxr, r.f. tubes - things seemed to get better.  I rocked the Mhz
knob for a while and pretty soon I was picking up a West coast noon net,
with signal coming in pretty good and some very strong.  It seemed to be on
a par with the 390a at that point - at least it was acting like a radio
where I could peak the background noise with the ant. Trim.  So I'm thinking
there is a dirty switch contact in there someplace,  maybe under the rf
chassis and it seems only to be affecting the 4,5,6,7 Mhz ranges.  The lower
bands seem to always work and the higher bands seem to always work.  So I
left the set on for a couple of hours and it continued to be ok on 7 Mhz
range but when I went back after about 3 hours, it was back to nearly dead
not able to hear the calibration oscillator and then only weakly on 7 range
and only slightly better on 4,5, and 6,  after some moving of the Mhz knob
but I wasn't able to revive it to the former state of operating much better.
I going to start loosening up the front panel screws.... Roger,  I remember
the post on alignment of the switch - I may still have it in my mail here -
will take a look,  Dan.  

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Flowertime01 at wmconnect.com
Sent: Wednesday, April 27, 2005 11:35 AM
To: r-390 at mailman.qth.net
Subject: Re: [R-390] R390 Band Switch Alignment

Fellows,

Please I need some help to go out to Dan,

Some where last month I put up a post about why we should pull the RF deck
and do the band switch adjustment by inspection of the switch by eyeball.
Because the switch sections are not all exact and wonderful.

My old sent mail has determined that I sent that post to long ago and
deleted it for me. I just love computers.

If someone has a copy, will you please put it back out here again.
Thank You.

Dan has an R390 that is weak in a couple of bands. It sounds as if his
receiver needs a band switch adjustment. It also sounds as if he needs some
pointers on doing a deoxit of all the switches, crystal sockets, tube
sockets and deck connectors. Some pointers from old post may be useful to
Dan on this subject as well.

Thanks

Roger KC6TRU


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