Laurehk Mfg. Co. L-65
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|Manufacturer:||Laurehk Mfg. Co.|
GENERAL DATA. The alignment of this recetver requires the use of a test oscillator that will cover the frequencies al 456, 600,1400 and 1720 KC and an output meter to be connected across the primary or secondary of the output transformer. I possible, all alignments should be made with the volume control on maximum and the test oscillator output as low as possible to prevent the AVC from operating and giving false readings.
CORRECT ALIGNMENT PROCEDURE. Remove the chassis from the cabinet and set on a bench taking care that no iron or other metal is near the loop. Do not make this setup on a metal bench. The Intermediate frequency (I.F.) stages should be aligned properly as the first step. After the IF. transformers have been properly adjusted and peaked, the broadcast band should be adjusted.
I. F. ALIGNMENT,
With the gang condenser set at minimum, adust the test oscillator to 456 KC and connect the output to the a of the first detector tube (12A8GT) through a. 05 o 1 mid a denser. The ground on the test oscillator should be connected-the chassis ground. Align all three I.F. trimmers to peak or mo num reading on the output meter.
BROADCAST BAND ALIGNMENT. Connect the test oscillator to t antenna of the set through a 200 mmfd. (. 0002) condenser. W the gang condenser sol at minimum capacity, set the test oscilla at 1720 K.C. and adjust the oscillator (or 1720 KC trimmer) gang condenser. Next-set the test oscillator at 1400 KC, a tune in the signal on the gang condenser. Adjust the anter trimmer (or 1400 KC trimmer) for maximum signal. Next set the ti oscillator at 600 KC, and tune in signal on condenser to check alignment of cells.
Voltage shown on the docuit diagram are from socket terminals to chansta base. Lo measuring voltages use a voltmeter having a resistance of at least 1000 ohms per volt. Allowances should be made for variations in line voltage.
Lack of sensitivity and poor tone quality may be due to any one or a combination of causes such as weak or defective tubes or spe open or grounded bias resistor, bypass condenser, etc. Never attempt to realign set until all other possible sources of trouble have first thoroughly investigated and definitely proved not to be the cause.
NOTE: IT IS ABSOLUTELY NECESSARY THAT AN ACCURATELY CALIBRATED TEST OSCILLATOR WITH SOME TYPE OF OUT MEASURING DEVICE BE USED WHEN ALIGNING THE RECEIVER AND THAT THE PROCEDURE BE CAREFULLY FOLLOWED, OTI WISE THE RECEIVER WILL BE INSENSITIVE AND THE DIAL CALIBRATION WILL BE INCORRECT. THE TRIMMERS WILL BE REFER TO BY THEIR FUNCTION AS INDICATED ON THE PARTS DIAGRAM.