[R-390] R390 Band Switch Alignment

[Jim Miller]

Could be the xtal oscillator.  Try giving the xtal trimmer caps for the 
questionable bans a few spins to work through any oxidation, then repeak 
them.  Also be sure no slug racks are sticking.  Give them a tap with your 
finger to be sure they pop into place and see what happens.
----- Original Message ----- 
From: "Dan Merz" <djmerz at 3-cities.com>
To: <Flowertime01 at wmconnect.com>; <r-390 at mailman.qth.net>
Sent: Wednesday, April 27, 2005 6:19 PM
Subject: RE: [R-390] R390 Band Switch Alignment


> 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
>
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>