Thank you Craig and Bear. I have a new 2uf capacitor on the way.
Since this is an AGC circuit, I thought that the value of the capacitor would be fairly critical. I guess what you are saying is that if you change the 2uf to, say, 1uf, it would still be "slow" but just not as slow. Is that right?
Now I just hope that the RF subchassis doesn't develop any problems. I'm afraid that would be beyond my meager skill set.
thanks again,
Ron W8ACR
Ron,
The R390/A receiver is not a half way fix-it receiver. They are old, get that fact between your ears.
Looking at some of my notes:
#1: Replace all know caps that have failed. Most of these are BBOD's
a: two in the panel & frame section
b: four in the RF deck
c: nineteen in the IF deck
d: nine in the AF deck
#2: Refer to the Y2K manual, chapter 6. Follow step by step alignment procedure. Mechanical is first! If the mechanical ain't right, ain't nuthin right! Then electrical alignment.
#3: Have fun finding the rest of the bugs.
The RF deck removal has never been joy for me, hate that part. The Y2K shows how, get help if needed. Has to be done! Believe me when you have completely gone through a R390/A, replaced the BBOD's, fixed the bugs; they are a joy to use.
They are not a band cruiser! Designed to be turned on, left on 24/7 for six months at a time, mostly on one frequency. On AM they are among the best of the vacuum tube battle mode receivers. The mechanical filters eliminate most of the frequency hogs in the AM getto. Not bad for a receiver first released around 1954.
Properly restored you will hear other stations in the QSO that other can not!
Regards,
Craig