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-   -   No AM broadcast band reception on Zenith TO 3000-1 (http://www.videokarma.org/showthread.php?t=269640)

Jeffhs 10-12-2017 01:57 PM

No AM broadcast band reception on Zenith TO 3000-1
 
Greetings.

I have a Zenith TO 3000-1 radio (an eBay find several months ago) which works and sounds great, but has no reception on the standard broadcast band. I was told by a VK member (Broadcaster, IIRC) that this problem is caused by a shorted transistor, but I am not sure which transistor out of the 12 in the radio is bad. I obviously do not want to "shotgun" replace every transistor (though I could, since I have another TO 3000 in storage) because all other bands, including FM, work very well. I am thinking the band switch might have one or more corroded or defective contacts, since the other AM bands (SW) came to life when I jiggled the switch a bit; however, trying the same trick on the BC band did not produce the same results. I downloaded the service manual and now have it as a .pdf file on my computer, should I need it for further troubleshooting.

Thank you.

tom.j.fla 10-12-2017 03:44 PM

Jeff, check your MW osc coil. On my D-7000 and ROYAL 7000-2 those coils were open. All the best,Tom.J

jr_tech 10-17-2017 02:44 PM

There are 3 transistors in the 3000-1 that are not also used for FM reception or audio. These are the 121-349 AM RF, the 121-351 AM Mixer and the 121-350 AM Oscillator. They are located in the upper left corner of the chassis (as viewed from the back).

However, it is unlikely that any of these is bad if your Shortwave bands are still working.

jr

Sandy G 10-17-2017 05:16 PM

There is a good article on properly cleaning the bands on TOs in this month's "Electric Radio". Likely more geared to the Tooob versions, but I'd imagine the soiled state sets could benefit as well.

Gregb 10-31-2017 09:11 AM

I had the same issue with my 3000-1 and it was the AM osc transistor. Changed it out and away it went.

Gregb

jr_tech 10-31-2017 03:47 PM

Quote:

Originally Posted by Gregb (Post 3191440)
I had the same issue with my 3000-1 and it was the AM osc transistor. Changed it out and away it went.

Gregb

Were the shortwave bands still working ok? AM was the only dead band? :scratch2:

jr


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