Quote:
Originally Posted by Jeffhs
I have a Zenith TO-3000-1 radio which I won in an eBay auction a couple days ago. The seller said, in his item description, that the radio "works (but has) no cord". I won the auction and received the radio via FedEx a few days later. The set works very well on FM, but not so well on SW (I can receive a few stations on SW, however, such as WRMI in Miami and a few others) and is completely dead on the AM standard broadcast band; the dial calibration is way off on all bands as well. I am extremely reluctant to do anything with any of the alignment adjustments on the chassis, for fear I will mess up this set the same way I messed up my first TO-3000-1.
What could silence the AM broadcast band (but not the others) in a solid-state T-O? I had no reception at all on any band except FM when the radio arrived here, but I was able to get the SW bands working (albeit with extremely weak reception) by jiggling the band switch. I'm thinking the switch is badly in need of a good cleaning. The radio has a 1965 date stamp on the chassis, which of course means the set was built over fifty years ago. I bet that switch hasn't been cleaned since the radio was new.
Note: I said the seller's item description for this radio stated the radio "works" but there was no cord. I knew he meant no batteries or AC wall wart; fortunately, I had an exact replacement wall wart that worked perfectly. However, I do not believe he was being entirely honest regarding the condition of the radio when he said it "works". That is, the set does in fact work very well on FM and picks up a few stations on shortwave, as I mentioned, but the AM band is completely dead.
I would not consider any radio with these problems a 100-percent "working" set. I do wish the seller had been more honest regarding the radio's condition; if he had, I would have looked a bit longer on eBay to find a TO 3000 that worked, and well, on all bands.
I am tempted to give this seller negative feedback due to the inaccurate description; however, I will not return the radio, as I believe it can be made to work again as it once did. Since I get stations on shortwave, after all, the set must be working for the most part. I'm tempted to think the only problem is the alignment is off, especially since the dial calibration is off by about 1 MHz on FM (and probably on AM/SW as well). I don't want to fiddle with the alignment adjustments myself, since I do not have a signal generator; that is exactly how I silenced my first T/O 3000 a year or so ago. I don't want to make the same mistake with my "new" TO 3000.
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If it took a lot of jiggling of the band switch to get SW to work, begin by cleaning it and inspecting solder joints on and around it. Get SW to work positively before proceeding to diagnose AM. Reception being dead could be a bad transistor, open coil, bad electrolytic cap, dirty contacts, etc. A bad local oscillator would definitely kill reception completely too, you could try the trick of running another radio beside this one to verify if the local oscillator works. If it works on SW it more or less rules out the parts common to SW and AM, and leaves you with coils and switches.
The fact that dial calibration is off tells some someone else has already messed with alignment too. An RF signal generator is small and can be had cheaply. Don't be put off by past failures with alignment, if you use a working signal generator and follow the alignment instructions exactly you can't really make it worse.