MODEL 1001 CHASSIS 19 RSME

ALIGNMENT PROCEDURE Correct alignment is of extreme importance in all wave receivers. The receivers are properly aligned at the factory with precision equipment and realignment should not be attempted by the service technician until all other causes or faulty operation are corrected.

In order to properly realigo the receiver the following equipment is necessary:
2. A signal generator which will provide an accurately calibrated signal at any frequency from 262 kilocycles to is megacycles. The generator should have adjustable signal output.
An output audio voltmeter of the low voltage typo to be connected across the moving soil of the speaker. This should be capable of providing a readable. deflection for relatively low output levels to avoid the effects of overload.
3. An insulated or non-metallic screwdriver for the adjustment of trimmera.

IF ALIGNMENT 262.5 KC
1. connect the output meter (low scale) across the loudspeaker voice coil. Turn the wave band switch (outside of tuning knob) to its left-hand or counter-clockwise position. This brings the red indicator for broadcast band to the top. Turn the volume control to its maximum position.

2. Turn the variable selectivity (center bottom knob) to the left or sharpest position. Put tone control on brilliant or clockwise position with selectivity Control held all the way to the left or counter-clockwise loosen set screws of collars, which actuate variable selectivity coupling and rotate until the drive cables are drawn out as far as possible without forcing. Tighten set screws in the collars. This adjustment assures maximum selectivity and should be checked before IF Alignment is done.

3. connect the test oscillator ground to chassis and the "hot" lead from the test oscillator to the grid of the 6L7 converter tube through a series .1 mfd condenser. set test oscillator to 262.5 kc.

4. with variable selectivity control in sharpest position adjust IF alignment screws, c14, C15, of output transformer, (directly behind tuning condenser) to maximum output reducing output of test oscillator to keep the meter reading on scale as alignment proceeds.

5. Adjust alignment screws, cl2, c13, of input transformer (adjacent to electrolytic condenser) to maximum output as described above.

6. Readjust all four alignment screws to insure accurate ali znment. Always use the lowest possible output from the test oscillator to preclude the possibility of automatic volume control action confusing proper adjustment.

ADJUSTMENT OF WAVE TRAP
Connect test oscillator to antenna and ground terminals of the receiver using a .00025 Mfd condenser in series with the Antenna terminal. With oscillator set at 262.5 kc adjust antenna trap alignment screw c4, for minimum signal increasing output of test oscillator as a minimum is reached.

RF ALIGNMENT (Broadcast " A " or " Red " Band)

1. With test oscillator connecting antenna post through .00025 Mfd as above set signal generator to 1400 kc.
2. Set dial scale, hour and minute hands, to 6 o'clock when gang condenser is fully meshed at maximum capacitance.

3. set dial to calibration mark 1400 kc using hour hand to Indicate frequency (no further attention need be paid to position of minute hand which is used merely for convenience in logging stations by " TIME "). Adjust broadcast oscillator trimmer condenser c16, for maximum output meter reading. If it is found that two peaks occur within the range of the trimmer action use the one in which the trimmer is in its lowest capacitance or counterclockwise position.

4. Adjust detector input trimmer C9, to a maximum.

In some receiver, C9, is a separate trimmer located on the range switch shield under the chassis rather than in the top of the coil can. In these models c8 is a 100 mmf fixed Mica Condenser instead of the variable trimmer shown on the diagram.

5. Adjust the Antenna stage trimmer c5, to a maximum,

6. set test oscillator to 600 kc and tune in the signal, then adjust broadcast oscillator padder c20, for maximum output. This padder is mounted under the chassis at the side of the RF "deck. " This adjustment is the outer nut of the concentric type passing condenser. Rock the condenser back and forth a degree or two in order to obtain proper maximum.

7. Repeat the 1400 kc adjustments described under 3, 4, 5, for greater accuracy. The output of the test oscillator should always be kept at the lowest output which will allow sufficient meter awing since this assures greater accuracy of adjustment.

Short Wave " B " or " Green" Band

1. Turn the wave band switch to the "B" or " Green " position. Leave the oscillator connected as above but with its output set to 6000 kc and the .00025 condenser replaced by a 400 ohm resistor. Set dial scale to 6 mc on the green or middle band, adjust " B " band oscillator trimmer condenser cl7, for maximum output observing as before that the proper point occurs at the minimum or counter-clockwise position of the screw if two points are found.

2. Adjust detector input " B " band trimmer condenser c6, to a maximum while rocking the tuning condenser slightly for maximum response.

3. Adjust Antenna stage " B " band trimmer c6, for maximum output

4. set the teat oscillator to 2000 kc and tune in the signal. Adjust " B " band oscillator padder condenser c19 for maximum output while rocking tuning condenser as described above, This adjustment is the inner scrow of the concentric type padding condenser.

5. Repeat operations 1, 2, and 3 to assure precise alignment

Short Wave "C" or "Yellow" Band

1. with test oscillator connected same is for " B " band and set to 18000 ko (18 mc) set dial scale to 18 mc on inner or yellow band.

2. Adjust C band oscillator trimming condenser cl8, for maximum response. Use lower capacity or counter-clockwise response point.

3. Adjust " C " band detector input trimmer c11, to a maximum, " rocking tuning adjustment to obtain greatest output.

4. Adjust antenna c band trimmer c7, for maximum response.

* The adjustment of the detector input trimmers on the " B " and " C " bands by the procedure outlined above is advisable as contrasted with the usual method of trimming without rocking the tuning adJustment because slight couplings through the tube circuits tend to disturb the oscillator frequency as the detector is tuned. This procedure should be followed on any type of all wave receiver.

Part of the production of Model 19 Incorporated certain circuit alterations which are shown in the insert enclosed by dotted lines on the circuit diagram of Page three. The parts placement diagram on Page two is a composite drawing showing the position of parts for both types of receivers. Parts dotted on this diagram refer to those shown in the insert of the schematic diagram. Circuit elements c31 and r17 are not used when dotted connections are employed.

When the variable selectivity control is in "tune" or narrow position certain 6K7 IF tubes may exhibit a tendency toward regeneration or instability due to control grid to plate capacity coupling. This may be "neutralized" by using several turns of twisted hook-up wire connected between the plate of the IF tube and blank lug of the RF socket which is used as a tie point for the AVC return. This is shown on the parts placement diagram.

Excessive hum in this model has been found to be due to defective 6H6 and 6C5 tubes. Replace each tube in turn with a tube known to be normal in this respect.

In checking the circuit with a continuity or ohmmeter it is wise to follow the schematic diagram in orderly fashion starting at the antenna and ground connections and proceeding to the speaker circuits.

REPLACEMENT PARTS & PRICE LIST

VOLTAGE CHART

Measurements from elementa to chassis-1000 ohms per volt Meter Line Voltage - 115v. 40. AC.
RF negative grid bias 5.0 volts
6F6 negative grid bias 18.0 Volts.
AC RMS each plate of rectifier to center tap 325.0 volts
Total current drain 110 Ma. E drop across speaker field 50.0 Volts