[R-390] New Member cont'd

[Barry]

Hi Wes,

Welcome to the group.  Glad the radio at least works to some extent for you.

One thing to mention.  You might want to avoid running it until you check out a potential problematic capacitor on the IF deck (C556 I believe).  If it is shorted or leaks excessively, it can damage/destroy whichever mechanical filter happens to be switched in at that time.  In this case, if you rotate through all bandwidths, you can destroy all four filters.

Since yours works in all positions, that cap is probably still good but is a risk factor that is easily avoided.  Search the archives and/or the net for more info on this.

Oh, and you can simply connect a low-impedance speaker to the 600-ohm output.  You'll lose a bit of volume and fidelity, but it will work.

Again, welcome.

Regards,,
Barry - N4BUQ

----- Original Message -----
> From: "Wes Bolin" <k5apl at yahoo.com>
> To: r-390 at mailman.qth.net
> Sent: Thursday, March 7, 2013 8:20:22 AM
> Subject: [R-390] New Member cont'd
> 
> Thanks to all who have welcomed me and have passed on tips,
> recommendations, and sources of information about my R390A.
> I purchased it last week at a hamfest; very dirty but physically
> looked to be complete. The owner said "it worked the last time
> I turned it on".  Brought it home and powered it up- straight off
> 120VAC (no variac).  Had to use earphones cause no 600 to
> 8/4 ohm transformer (its on order).
> I was lucky.  The calibrator worked on 28, 7, and .7 MC bands. Could
> barely hear a strong BCB station, and copied some SSB
> on 40M.  Selectivity 'worked' on all positions. BTW the calibrator
> was good signal strength. BFO 'worked'. I could see that a
> bulb was out, and no indication on Audio Meter. Fiddled with other
> knobs and switches and they apparently are 'good'. Turned
> it off and put it back on the shelf until my present project is
> finished (Hammarlund SP600).
> Might take me a few weeks to finish up my project, so in the meantime
> I will gather more info and parts for updating it.  The
> cosmetics of the front panel are very good, but dirty. The knobs will
> need re-paint.  The Carrier Meter works but is very opaque
> and smeared glass, on the inside of it. Any ideas how to clean it on
> the inside?
> It is very reassuring to have a source to go to when a question or
> need arises during this restoration.  Thanks again.
> Wes
> Motorola #1128