Antenna trimmers (parallel tuning condenser) are usually adjusted for the high end of the band. This may be a frequency near the end of the dial or at the end of the dial, depending on the set and the preference of the manufacturer, and the accuracy of the tuning condenser at the very end of the band. For broadcast, some sets will use 1400 KC as an alignment point.
Antenna padders are adjusted towards the low end of the band. On broadcast this is often 600 KC. I don't know of any radios that have antenna padders, though.
Oscillator trimmers are adjusted like antenna trimmers. Oscillator padders are adjusted like antenna padders (though again, I don't know of any radios with antenna padders). A padder is in series with either the tuning condenser or its associated coil.
None of the above should be adjusted unless you know that your IF transformers are perfectly adjusted.
Thomas
T.
http://www.nostalgiaair.org/PagesByModel/333/M0025333.pdf
Adjust A, B, C, and D to the IF. You should probably do this with your generator connected to grid 4 of the 7B8.
Send IF signal through antenna circuit for this next procedure. Adjust E for MINIMUM signal.
Adjust F and G to a frequency near the top of the broadcast band. Adjust F preferrably with an actual station to minimize inaccuracy of your generator.
Adjust J at 600 KC. Recheck dial for accuracy, and touch up at each end using F and J. Once both ends and everything in the middle is perfect, touch up G at the high end. If adjusting G at the high end produces unfavorable sensitivity at the low end, try adjusting it at 1400 KC instead. Also, try adjusting both F and G at 1400 KC if adjusting them at the high end of the band produces unfavorable results. Stations should line up well across the dial, if not perfectly. They should not be off by more than 10 KC. If they are off in the middle, and fine at the ends, this might also mean that your generator was not accurate with the IF frequency. If you have a long wave digital receiver, you can tune in the IF and check it against the digital frequency read-out for perfect results.
K and M should be aligned at the high end of the short wave band. If this doesn't produce favorable results, try aligning them at about 1/5 to 1/4 of the way down from the top of the band. Hopefully stations at the very low end will line up well. You can touch up on the antenna trimmer so that both ends are equally sensitive. If this receiver is built well, which most Zeniths are, and if you knew the exact alignment frequencies, it will be possible to get perfect alignment across the dial. If alignment at the low end of the dial is impossible no matter what you do, you can try shifting oscillator coil wires to change capacitance. No padder is provided for this procedure. Since the radio was probably aligned well at the factory, the wires should already be in proper place.
Adjust the police band antenna trimmer for maximum sensitivity towards the high end of the band, or 1/5 to 1/4 of the way down from the high end, whichever produces better results across the band. The police band should, in theory, line up properly once the broadcast and short wave bands have been adjusted properly.
Thomas
:Well, thankfully the parts list describes what each trimmer is, otherwise, without a perfectly clear head, I'd never be able to figure out what half of those trimmers are.
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:Adjust A, B, C, and D to the IF. You should probably do this with your generator connected to grid 4 of the 7B8.
:
:Send IF signal through antenna circuit for this next procedure. Adjust E for MINIMUM signal.
:
:Adjust F and G to a frequency near the top of the broadcast band. Adjust F preferrably with an actual station to minimize inaccuracy of your generator.
:
:Adjust J at 600 KC. Recheck dial for accuracy, and touch up at each end using F and J. Once both ends and everything in the middle is perfect, touch up G at the high end. If adjusting G at the high end produces unfavorable sensitivity at the low end, try adjusting it at 1400 KC instead. Also, try adjusting both F and G at 1400 KC if adjusting them at the high end of the band produces unfavorable results. Stations should line up well across the dial, if not perfectly. They should not be off by more than 10 KC. If they are off in the middle, and fine at the ends, this might also mean that your generator was not accurate with the IF frequency. If you have a long wave digital receiver, you can tune in the IF and check it against the digital frequency read-out for perfect results.
:
:K and M should be aligned at the high end of the short wave band. If this doesn't produce favorable results, try aligning them at about 1/5 to 1/4 of the way down from the top of the band. Hopefully stations at the very low end will line up well. You can touch up on the antenna trimmer so that both ends are equally sensitive. If this receiver is built well, which most Zeniths are, and if you knew the exact alignment frequencies, it will be possible to get perfect alignment across the dial. If alignment at the low end of the dial is impossible no matter what you do, you can try shifting oscillator coil wires to change capacitance. No padder is provided for this procedure. Since the radio was probably aligned well at the factory, the wires should already be in proper place.
:
:Adjust the police band antenna trimmer for maximum sensitivity towards the high end of the band, or 1/5 to 1/4 of the way down from the high end, whichever produces better results across the band. The police band should, in theory, line up properly once the broadcast and short wave bands have been adjusted properly.
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:Thomas
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