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Weak/No Volume on FM Band - 51-934 - Printable Version

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Weak/No Volume on FM Band - 51-934 - winniefs - 10-02-2011

I'm having problems with the volume; sometimes I get no volume when I turn the knob to the FM band and other times only a very low volume and very few FM stations. Any ideas for a solution? When AM band is playing I get really good reception and lots of AM stations. I have sprayed the AM/FM switch but this didn't help. At the rear of the chassis on the left hand side (viewed from the rear) there is a single lead about 4" long and a dual lead same length. I'm assuming these should be connected (soldered)somehow to the 3 terminals on the rear of the cover. I've tried different combinations of hooking them up but I don't get much change in volume. Could someone explain how each of the 3 wires should be connected and if any of the 3 screws should be bridged when in AM or FM.

Thanks for any help;
Andy

Re: Weak/No Volume on FM Band - 51-934 - winniefs - 10-03-2011

Does anyone out there have a Philco 51-934 they could pull the back off of and see how the 3 leads are arranged??
Thanks;
Andy

Re: Weak/No Volume on FM Band - 51-934 - Ron Ramirez - 10-03-2011

I was just looking at the schematic of the 51-934.

Then I looked over at the shelf where Debbie has put some of the radio she has bought for her collection of plastic and bakelite radios...and, lo and behold, there was a 51-934!

It looks like the dual leads should connect to terminals 1 and 2 (FM), and the single lead should connect to terminal 3 (AM). The original setup had a wire connected to terminal 1 that connected to a piece of metal that wrapped around the AC cord, acting as a capacitor to make the AC cord act as an FM antenna. This setup works okay on local FM stations, but isn't much good for DX.

Re: Weak/No Volume on FM Band - 51-934 - winniefs - 10-04-2011

Ron; Thanks very much for your reply. I hooked up the dual leads to terminals 1 and 2 and the single lead to terminal 3. My set has the wire which is wrapped around the AC cord and I connected the end of it to terminal 1 also. With this setup I still cannot pull in any FM clearly; only can hear 1 very, very weak staion with the volume cranked up to full. I have an exterior antenna which I assume is supposed to be connected to the 2 fm terminals. I did align the am band and now get far more stations than before the alignment. So I figure maybe take a crack at aligning the FM band. This will be very difficult to do because it's hard to get my alignment tools at the openings of the tuning coils due to tight access even with the chassis pulled from the cabinet.

Andy

Re: Weak/No Volume on FM Band - 51-934 - codefox1 - 10-04-2011

I think I looked this one up a day or two ago. Terminals one and two are for a 72 ohm fm antenna with one as the center conductor. When using a gimmick AC coupler the position of the line cord is really critical, and completely useless in some situations. You could use a 72 ohm to 300 ohm transformer either directly or after a length of coax cable to a directional dipole which would be about a yard of old fashioned antenna lead shorted to itself on the ends and hooked up at the center of one of the leads, but this is very directional. Any way, you'll get it.

Re: Weak/No Volume on FM Band - 51-934 - winniefs - 10-04-2011

codefox1; thanks for the information. Maybe I'll try the antenna you sugessted. There is one on E-bay right now; "indoor am fm 300 ohm stereo radio T dipole antenna" item # 250891009743. Would this be the antenna I'm after???

Thanks;
Andy