[R-390] R-390 Problem

[Flowertime01 at wmconnect.com]

Gary,

Easy one first, Young man having a tube receiver warm up in about a minute 
is normal. It ain't a transistor you know. Warm up use to be part of all 
receiver and transmitter operation.

I do not think the 120 volts is the magic point.

Things that come to mind: In all of these, you reach a strike point where 
the power will flash across the open and the circuit then goes into 
conduction and the receiver "appears" to work.


Tube filaments open filament eye ball all the tubes in the dark.
Crud in a connector or tube socket
Cold solder joint
Failing cap.

Turn the radio on and just leave it on. At some point the problem will fall 
apart and make it easy to find the problem.

Thump the receiver on the bench a couple times. Pick it up 4 inches and let 
it free fall back to the bench squarely.

If you know your receiver knobology sequence, you should be able to front 
panel the problem down to a specific tube stage or two tubes.

I believe that sequence is in the Pearls Of Wisdom. But you need to learn 
it before your receiver goes south so you have some idea of what your trying 
to hear when you spin a front panel knob from stop to stop. As a memory aid 
you can read the sequence off the schematic from head phones back to antenna.

Stick with it. these are in fact common problems. Do not let the way you 
stumbled onto the problem miss lead you into thinking you have some real 
exotic problem. 

Interesting as it may be, It is just another receiver problem.  Yesterday 
it worked, Today it does not work. Someone thing has gone wrong. While 
locating the problem, do no harm. Find and fix the problem. 

Roger AI4NI</HTML>