Thanks for your help,

Dave
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: : : : : : : : : : : :Herr David . . . . . . . : : : :From the reading of your given information. : : :It seems to be a given that the tuning transport is running from one end end of the AM band to its extreme other end, with the power solenoid tripping and retensioning the main tuning drive spring, either at its end of travel OR at any intermediate point, AS is deemed necessary. : : :What you seem to be fixated upon is the " contacts" aspect of the tuning stop relay. : : :What lets try, evaluatively, is to get the unit scanning across the AM band and then take note of the armature of that tuning stop relay. Then see if pressing a fingertip upon its top and pressing it down to its mechanical STOP limit, such as it would be as when being electrically activated. : : :What we are interested is is IF that carriage stopped moving when the armature was pressed to its limit . . . . .it should have. : : :That relay armature is ADDITIONALLY pressing a small metal tab down into an area below it where there is a spinning a "AIR PROPELLOR IMPELLER BLADE " which is at the teminus of a long staged gear train. : : :The tab blocks the impeller and the gear train freezes and locks the tuning at that point. : : :Later on whan you want to resume auto seek tuning feature , it initiates the deactivation of the power to the stop tuning relay, and the armature pops up and lifts up the limiting tab and then the air impeller blade can start to spin again with the gear train moving, to drive the tuning carriage on up the band. : : : :The electrical aspect of autotuning is dependent upon a good alignment to attain a hefty AVC vooltage, which is then capable of being voltage divided down for its "sensitivity" auspices (local-distant). : : :The AVC sample is then fed into that 12AU7 which is circuitively configured as a Schmitt trigger driver to feed into that tuning stop relay. : : :Now as your tuning mechanical drive comes into the capture range of an AM signal, its AVC level will ever be inreasing up to the threshold where that trip threshold of the Schmitt trigger is met . : : :At that critical voltage threshold point the stage switches and power is placed to the relay . . . .SNAP. : : :There in no gradual relay action, but a well defined . . . . .SNAP ACTION THRESHOLD . . . ..by virtue ofthge utilization of the adjunct Schmitt trigger designs utiliztion. : : : :I hope that this minimalist explanation suffices, mainly from "the fingertip test" and the electronics technique, but I could also see that tou would also benefit from the mechanical aspect should you ever have torn down a Big Ben alarm clock and see its sequentially evolved gear train. : : :Try to move gears at one end and they are almost immobile, but those on down the train spin ever so faster. : : :Try spinning that other ends gears and they move effortlessly, but require scores of turns to show a micromovement of the "STRONG" gear. : : :A like comparison . . . .completely fitting this mechanisms structuring would be a music box movement. : : :In its construction there is a strong main spring which feeds a gear train, with an intermediate power take off to spin a studded drum to pluck musical tines. That gear train goes on to be further sped up to the extent thah its gfinal gear ties into a flat bladed "air" impeller. That air braking action acts as a speed governor for the whole gear train. (Sound familiar ?) : : : :Another mechanical counterpart would be the old vintage wind up clock which we used to have in automobiles. : : :As the main spring looses tension, a switch closes to activate a solenoid which reloaads thge spring tensioning . (Sound familiar ? ) : : : :Standing by . . . . . . : : : : : :73's de Edd : : : : : I just hate it when my foot falls asleep during the day because that means it's going to be up all night. : : : : : : :

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::Bud,
:: I understand how it's supposed to work. But with metal fatigue, those relay contacts are unstraightenable. The force of the part of the relay that moves, bends the normally closed contact. This is the problem.
:: Now I have it so the relay is energized when the wonderbar is pressed and de-energizes when the button is released. Now there's no action from the tube to either keep the relay energized or de-energize it. I'm sure there's no problem electronically. It's all to do with those lousy relay contacts. They are mangled.
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::Thanks,
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::Dave
::::Hello All,
:::: The signal seeker seeks and clicks at each station found but keeps on seeking instead of stopping. It's also able to retun at the end of the band. So it seems to be very close to working.
:::: What's going when it does this?
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::::Thanks,
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::::Dave
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:::Are you repairing radios for customers? If so, I strongly recommend you get some service literature for the more complicated sets like the Wonderbar. You need to understand the mechanical and electrical aspects of this tuner. It will make troubleshooting a lot easier.
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