[R-390] Sunday's Line & Local Report

[Craig Heaton]

As the sweet young thing that delivers the mail would say, "The continuing
saga of the boombox".
 
Progress was made today, I hope. Never trust a  Sprague TO-6A to determine
if a capacitor is good enough for C603, new, used, NOS or otherwise.  So
much for the above, on to the results of the IF testing.

Only a single description is needed, both the Amelco and Motorola were close
enough. Carrier level meter varied slightly.

The receivers & sig-gen (HP 8640B) were tuned to 3.800MHz and allowed to
warm up for 1-1/2 hour or so. Pin #1 of V507A was the test target. I think
this is far enough down the line to compare IF's. I don't do this every day,
hope I've read the scales correctly on the test equipment.  

O'scope with a probe was connected to pin #1, sig-gen cabled up straight
into the balanced antenna input. Function switch was set at AGC. Then the
sig-gen was cranked up to get a mid-scale reading on the carrier level
meter, 50DB. This was @ 0.5mV RF output. Next the 400Hz audio output was
selected and set for 100% modulation. The scope read about 3mV. 

Then the output range switch on the sig-gen was rotated and output set
around .15V, carrier level meter was near 100, and the scope read 5mV. (on
both receivers) 

If the above numbers look good, keep them for future use. Time to visit  the
neighborhood capacitor store. Whatever it is, clues point to the AF module. 

Regards,
Craig