Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

49-906 FM hum
#1

I just finished my 49-906. Replaced all caps, out of range resistors and a few tubes. Alignment was done also.
AM is good and strong-no hum. FM picks up a few stations but has a hum all across the dial. It does almost go away when tuned to a station.
What did I miss?

http://www.nostalgiaair.org/PagesByModel...013675.pdf

Thanks,

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org

#2

You might try changing the 14F8 converter tube. If it has heater to cathode leakage, then the AC voltage for the filament will FM modulate the oscillator, causing a hum. It could also be the 19T8 tube, since different diode sections are used for FM.
#3

Thanks, I'll try a swap and let you know.

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org

#4

That did it! The 19T8 made a difference.

Thanks, Mondail,

Eric
The Villages, FL
Member: Philco Phorum, ARF, ARCI & Radiomuseum.org





Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
New Philco Repair Bench
I am sure this is the archive, and not the Chuck's site.morzh — 09:50 PM
Made mistake & did not label connection
It's not like we are good friends with that wire and can tell it from other ptetty identical looking wires. Why'n't you...morzh — 09:49 PM
Made mistake & did not label connection
I'm not sure why that wire wasn't covered in the video. I'm pretty sure the 6A8 won't work until that pin is grounded. Y...RodB — 09:47 PM
Made mistake & did not label connection
You'll have to forgive me, I am not sure what you mean.  Can you explain what you are really saying.  If anyone does not...georgetownjohn — 08:05 PM
Made mistake & did not label connection
Those are details better left to the ones who know. Maybe you disconnected the wrong end of the wire.RodB — 06:22 PM
Made mistake & did not label connection
Maybe this is starting to make some sense in my hard head.  Is this why the wire in question was not in the great Ron Ra...georgetownjohn — 04:34 PM
Made mistake & did not label connection
I was correct with the 6A8 pin connection's, 7 and 8 are connected to ground as well as the tube shield (the broken line...RodB — 02:41 PM
Made mistake & did not label connection
What does the dotted line representing that surrounds the tube in the schematic?georgetownjohn — 02:17 PM
Made mistake & did not label connection
Hello John, I have been there either label got lost or was not labeled ! Sincerely Richardradiorich — 02:15 PM
Made mistake & did not label connection
Sorry, it is a Philco 37-640.  Does that help?--Johngeorgetownjohn — 02:14 PM

[-]
Who's Online
There are currently 2963 online users. [Complete List]
» 2 Member(s) | 2961 Guest(s)
AvatarAvatar

>