[R-390]

[Bob Camp]

Hi

The first thing to do is to figure out *which* bands it does not work 
on.

If it's just random bands here and there with none of them next to each 
other then the crystal oscillator tube may be the problem. If it's one 
of two random bands then it *might* be a crystal but I have never seen 
more than one or two bad crystals in any one radio.

My bet would be that you will find that all the bands above or below X 
don't work or that all the bands between X and Y don't work.

Since some tubes are only used on some bands you can't even rule out a 
dead tube. II would bet you have a dead coil somewhere in there. Best 
bet is always the input coils. Between lightning and high power 
transmitters the input coils sometimes lived a short and sweet life. 
Next best bet is that the 17 MHz oscillator has died and everything 
that uses it is  out.

If it's input coils there are sources for rf decks complete with all 
the coils in them. If you have several radios to work on it may not be 
a bad way to go. If it turns out only one or two coils then I suspect 
that you can get them here on the list for a lot less than the price of 
a rf deck.

	Take Care!

		Bob Camp
		KB8TQ


On Jun 20, 2004, at 5:47 PM, Lee Bahr wrote:

> I went to the Arlington Ham Comm in Texas yesterday and bought my third
> R-390A.  It was a Motorola, serial # 1587.  All meters are intact but 
> the
> chap who sold it to me for $250 said it does not work on all bands and 
> he
> didn't  know what was wrong with it. He said he found it in a 
> corporation's
> disposable pile.  Now I have 3 of them to restore!  (The other two are 
> EAS
> units).  The Motorola unit looks clean and the front panel is nice but 
> not
> perfect.  All the covers are there.
>
> What would be the most logical reason for some bands not working?  I 
> guess
> crystals would be suspect and maybe switch contacts, if nobody was 
> screwing
> slugs around in the unit.  (I'll check to see if rack coil slugs are
> moving).
>
> Also, what do you guys think of the latest Electric Radio's article 
> (June,
> 2004) on improving R-390A audio?  I'm thinking of trying this if I 
> ever/when
> get my radios up and running,
>
> I just ordered the two sets of Hi-Res videos on the R-390A as well as 
> the
> set for the SP-600JX but they have not arrived from Hi-Res as yet.  My 
> two
> cap kits for my first two R390As have been sitting on the work bench 
> for
> weeks now.  Maybe the videos will get me going!
>
> Lee, w0vt
> Houston
>
>
> _______________________________________________
> R-390 mailing list
> R-390 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>