[R-390] R-390] I got my R-390 working!!‏

[Gene Beckwith]

Gents, 

It may be redundant...but in general...the old carbon composition 
resistors in the R390Xs and other heavy metal vintage rigs have a 
directional tendency to increase in value over time...with or without 
being in service...I don't know the chemistry and what happens to the 
resistive material...but even unused - nos - carbon comp resistors can 
and may change value over time...directionally to increase in value...

When rehabing a heavy metal rig...advise checking nos stock before using 
for replacement....

Really enjoying the notes here on the reflector...

73,

Gene
W8KXR


John Burke wrote:
> Jim,
> When I restored my 1954 Motorola R-390/URR I found a majority of the 2.2k ohm 1/2 watt 
> resistors in both the RF and IF deck to be well out of tolerance. I also had to replace several 
> other resistors for the same reason. The performance improved dramatically and several of the
> original problems were cured at the same time. Since I have been unable to locate a copy of
> the parts manual for the 390, I have been unable to ID the resistor manufacture but they are 
> smaller then IRC or AB 1/2 watters and have a rough texture to their surface. Also, the resistors
> in the power supply regulator are most generally out of tolerance due to the heat problem in
> this design, so take a look at them too. It's well worth the effort.  
> 73, John - W0ENE
> _____________________________________________________________
> 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
>
>