[R-390] Non-A alignment question

[Roy Morgan]

On Feb 23, 2011, at 11:04 AM, Paul Staupe wrote:

> ... a R-390/URR (non-A) ...no stations received.  I tried tuning it  
> up using the manual with my
> URM-25D and a VTVM on the diode load to no avail.

See if the IF strip is working (inject 455 kc in to the in put of the  
IF strip from the URM)

Then see what frequency the PTO is really on: use another receiver  
with a bit of wire as antenna stuck down into the PTO oscillator tube  
shield,  A bit of manual study will reveal what the PTO frequency  
should be.

Later, come to understand the mixing scheme and the frequencies  
expected at different parts of the radio.. Locate the test points on  
the RF module and inject signals expected, starting nearest the IF  
output.

NOTE:  If you are using the URM module that has a single capacitor in  
it, replace that thing before going very far.  It may well be leaky  
and let B+ into your URM attenuator, or let grid voltage leak off from  
the radio.

Roy

Roy Morgan
k1lky at earthlink.net
K1LKY Since 1958 - Keep 'em Glowing!