Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

Sounds like you have rotor to stator short in the antenna half of the main tuning capacitor. One (or more) of the plates is shorting out to the adjacent plate. It's shorted either by being slightly bent or because there's something conductive - like a tiny fleck of solder or a bit of corrosion - that's causing the plates to touch. With a strong light and a careful look, you may be able to see what's causing the problem.

With the tuning cap fully open, insert paper about the thickness of a business card between each set of plates to remove any conductive bits and maybe straighten a bent rotor or stator plate.

Tune the capacitor just to the spot where reception stops to see if you can find what's making the short.

:Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

:Sounds like you have rotor to stator short in the antenna half of the main tuning capacitor. One (or more) of the plates is shorting out to the adjacent plate. It's shorted either by being slightly bent or because there's something conductive - like a tiny fleck of solder or a bit of corrosion - that's causing the plates to touch. With a strong light and a careful look, you may be able to see what's causing the problem.
:
:With the tuning cap fully open, insert paper about the thickness of a business card between each set of plates to remove any conductive bits and maybe straighten a bent rotor or stator plate.
:
:Tune the capacitor just to the spot where reception stops to see if you can find what's making the short.
:
:
:
:
:
::Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

::Sounds like you have rotor to stator short in the antenna half of the main tuning capacitor. One (or more) of the plates is shorting out to the adjacent plate. It's shorted either by being slightly bent or because there's something conductive - like a tiny fleck of solder or a bit of corrosion - that's causing the plates to touch. With a strong light and a careful look, you may be able to see what's causing the problem.

Good thought, but after close inspection this does not seem to be the problem. I was able to get a business card in between each of the plates with out the card binding in any of the positions, still a good thought. After, tuning the dial in this lower region I can hear some stations coming through but they are very faint. Checked voltages at all the tube pins are they appear to be reasonable when compared to to the Zenith data sheet. Still at a loss to figure this one out.

::
::With the tuning cap fully open, insert paper about the thickness of a business card between each set of plates to remove any conductive bits and maybe straighten a bent rotor or stator plate.
::
::Tune the capacitor just to the spot where reception stops to see if you can find what's making the short.
::
::
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:::Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

First thing I have to ask if you checked the alignment per the procedure in the schematic. Another thing I see is a wavetrap (E on the schematic). I read somewhere that those used to be for filtering old maritime signals. Someone more knowledgeable than me may say if this could be the problem by attenuating the low end of the BC band. You may be able to remove the trap.

:Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

:First thing I have to ask if you checked the alignment per the procedure in the schematic. Another thing I see is a wavetrap (E on the schematic). I read somewhere that those used to be for filtering old maritime signals. Someone more knowledgeable than me may say if this could be the problem by attenuating the low end of the BC band. You may be able to remove the trap.

Thanks, I will look this over tomorrow.
:
::Started to work on my Zenith 6S222, completely recapped and replaced any resistor out of range, Checked the tubes and relpaced one , all the rest are OK. Powered up the radio and seemed to play OK. As I moved the dial pointer around I could see there was a problem. All the stations from about the mid point come in good and the stations from mid point to 550 do not come in. Touching my finger to the grid on the Det/Osc tube (6A8) brings these stations in loud and clear. I think this indicates that the audio portion of the radio is OK and the problem is in the RF section. But before I go any further on this project I thought it would be a good idea to seek some advice on this problem, Thanks.

Hi George,
This radio has a broadcast padder. It is in the corner of the chassis near the 6A8G. It may be defective or out of tune. It is labeled 'J' on the schematic.

Best Regards,

Bill Grimm

Hi Bill,
I looked over the broadcast padder, it seems to adjust OK, I will try to spray this with contact cleaner to see if this helps, Thanks

:Hi George,
: This radio has a broadcast padder. It is in the corner of the chassis near the 6A8G. It may be defective or out of tune. It is labeled 'J' on the schematic.
:
:Best Regards,
:
:Bill Grimm

Finally found the problem with this radio. I started by a complete recap and changing any resistor out of tolerance, and all tubes checked OK. Radio stated to play around 800 KHz and above. Any station below this you could hardly hear. I was lucky enough to have a Zenith 6S-223 that played great (same chassis) so I pulled the chassis out and compared the two side by side. What I finally found was a open winding in the antenna coil (mounted in a can on top of the chassis. Repaired this problem and gave it a final alignment and it playes nice all the way across the dial. Thanks again to everyone who helped me on this problem.