Quote:
Originally Posted by toxcrusadr
Were you getting any AM before or was the radio basically dead and the FM came to life with the new tube but not AM?
Got a schematic for this beast? I'm just wondering how separate the AM and FM sections are. Are they both using the 12AT7?
Has the set been completely recapped or are the caps original? If original there may be one or more bad or drifted interstage caps somewhere in the AM circuitry.
How about a dirty band selector switch?
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Thank you much for the prompt reply.
The AM section was working before I replaced the 12AT7. I had to replace the tube because a pin broke off the original.
On the schematic for the C845, chassis 8C02 (which is practically identical to that for the C835), the 12AT7 tube is identified simply as a converter, which leads me to believe it works for both AM and FM. I can't be certain about that, however, since the tubes in the C845 are wired in series, and the radio will not operate without all tubes in their sockets.
This radio has not been recapped, to the best of my knowledge (I got it used about five years or so ago), so there could well be one or more bad capacitors in the AM stages.
Dirty contacts on the band switch could be causing the problem. I don't have any kind of contact cleaner here, so I'll have to put off cleaning the switch until I can get a fresh can of cleaner at Radio Shack (the nearest RS branch store is perhaps ten miles from where I live; I don't drive, so it may be some time before I can get there).
I did mention in my post that I am getting very weak and garbled reception of a local AM station in the next town south of here, so I am thinking the AM stages must be working, at least somewhat. What puzzles me, however, is why, if the radio gets the local station (distorted though it is), I am not hearing any other stations anywhere on the dial.
