[R-390] Deaf R-390A

[Larry H]

Hi Ron,  Sorry to hear this - it may not be good news.  I hope it's not this, but check the wire P112-19 to see if it's grounded.  It's the filament line between the bfo and vfo tubes.  If it's shorted to ground, the 'regulator 3tf7' might have been blown.  Unfortunately, its right next to a ground wire in the P112 socket, number 18.  The easiest way to check is pull the 3tf7 and measure the element resistance, it should be around 15 ohms.  If its below 25 ohms, it might be ok.  If its open, pull the bfo tube and measure pin 3 to ground.   If it's shorted (low resistance is ok), you know the drill.  If it's not, wiggle the large IF deck connector and see what happens.
Since the 3tf7's are not cheap, I suggest putting a 12BH7 or 12BY7 in instead and adding the 2 jumper wires on the socket to make it work temporarily until you find the problem.
Good luck.
Regards, Larry
      From: TVComlGuy--- via R-390 <r-390 at mailman.qth.net>
 To: r-390 at mailman.qth.net 
 Sent: Thursday, May 26, 2016 12:48 PM
 Subject: [R-390] Deaf R-390A
   
Good afternoon to the group,
 
I recently picked up an R-390A from an antique shop that came from an  
estate. After changing the cap of death on the filters, I brought it up and it  
worked right off the bat. It started making crackling noises and I started  
wiggling connectors. When I got to P-112 on the I.F. deck it dropped out  
completely. I put some Deoxit on the pins and it started working again.  Then 
when I touched the plug it dropped out and wouldn't come back.  I  switched 
out the I.F. deck from a good receiver and it, too, didn't work.  When I 
put the working deck back in the working receiver it also doesn't work  now!  
 HELP!!!
 
73//Ron, KB0WAR
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