[R-390] R-390 Dilemma: Deaf RF Deck

[Flowertime01 at wmconnect.com]

Rick,

Read Roy's post. Follow his instructions.

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There are some common threads found in 50 year old RF decks.
These all come back to crud. Move the crud and the symptom changes.
But crud is crud.

Follow Roy's advise to spend the least time locating where your specific 
problem is.

Start on the third mixer and VFO.  with the receiver set above 8 Mhz.
You think the VFO is good because it works with the other deck.
Pull V204 a 6C4 and make sure you have B+ on the socket.

Put some 455Khz into E211 (< 150UV) Peak T208 while you are at it.
You could have a bad coax between the RF and IF deck. Missing B+ from a 
broken wire in the wire harness or the RF deck connector. This should be an easy 
test.

Run the generator up to between 2 and 3 Mhz. Roll the VFO around and get it 
to mix a 455Khz output.

You can move the signal injection back to E210. The same freq should couple 
through.

If this is a no go then you need to look at V203.

If this works move the generator up to mix with the crystal oscillator.

If this does not work then look for a B+ problem or switch alignment problem 
in the Crystal oscillator sub chassis.

Check the tube sockets for crud that keeps a tube from working.
Use a tube extender if you have one to test voltages.
Work back through the deck one stage at a time.

Better to test and inspect one stage and socket at a time than try and shot 
gun the whole deck.

The problem is locatable and repairable.
Good luck with it.

Let us know what you find.

Roger AI4NI