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Saba Freiburg Vollautomatic 125 - automatic tuning problems
So this was dropped (probably out of a 10 story building judging by how bent up the chassis was) by the postal guy.
First none of the AM bands were working -- this turned out to be broken ground connections in the AM RF circuitry which meant the local oscillator wasn't oscillating when switched to AM --- This radio is strange in that it uses the same tubes for both the oscillator/mixer and IF stages for both AM and FM -- then an elaborate switching mechanism to change frequencies.
Now the auto-tuning - this is what I can't figure out -- It will move in both directions and find a station and lock in on it -- but the motor won't stop running - it keeps vibrating, sometimes moves a little back and forth around the station.
I found some service information and tried alignment of the control transformer - for both AM and FM - this helped, but the motor still will not shut off completely -
On AM it moves very slowly between stations compared to FM and sometimes skips stations (more so when going backwards) - but the motor is more quiet after it finds one - is barely vibrating. On FM, it moves more quickly between stations, is less likely to skip one, but it is more active moving back and forth around a station after it finds one.
The tuning motor never completely shuts off unless I push the button to switch it to manual tuning.
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