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SCHEMATIC HOLLYWOOD ELECTRONICS
IF PRAK 455 KC
SHORTING PLUG MUST BE IN SOCKET " S " FOR A - C OPERATION.
115 VOLTS 60 CYCLE A - C
FOR D - C OPERATION CONNECT 310 VOLTS POSITIVE TO PIN 4 AND NEGATIVE TO PIN 5. CONNECT 6 VOLTS POSITIVE TO PIN 7 AND NEGATIVE TO PINS I OR 8.
BAND: - SWITCH SHOWN AT 1ST POSITION. SHORT WAVE BAND
BAND - SWITCH SHOWN AT 2ND POSITION COUNTERCLOCKWISE. BROADCAST BAND
The HE - 621 is intended to be supplied from a 115 volt 50 to 60 cycle A.C. source but if desired the jumper wires of the plug located next to the A.C. cord on the rear apron of the chassis may be removed and the plug wired as indicated on the diagram to allow operation from batteries or a battery pack.
INTERMEDIATE FREQUENCY ALIGNMENT
Prepare the receiver as follows: Remove the antenna completely. Band switch on " BC " or middle position. Set dial to a point near the high frequency or 1500 kc. end where no station is received. Turn tone and volume controls to maximum clockwise rotation Connect a signal generator to the stater connection of the tuning condenser section C2 RF or to the RF input grid (socket connection # 6) of the 7B8 tube. If there is no blocking condenser in the output lead of the signal generator, the lead should be connected through 8.1 Mfd. condenser instead of directly. Connect the ground of the signal generator to the chassis of the receiver or to the terminal on the antenna ground strip marked " G ". After the above connections have been made, set the signal generator for 455 Kc. 30 % modulated signal output. Now adjust the condensers on IF transformers 2532-1 and 2532-4 for exact resonance which will be indicated by maximum signal output. An output meter of the rectifier type should be used and may be connected through a suitable coupling condenser to the plate (socket connection # 2) of the 705 output tube or to the voice coil leads of the speaker. When making the final adjustments to the IF tuning condensers, it is advisable to use as low an input signal level as possible.
RADIO FREQUENCY ALIGNMENT
Replace the. 1 Mfd. condenser in series with the generator lead with a 400 ohm resistor. Connect the generator to the terminal marked " A " on the antenna-ground strip which is mounted on the rear apron of the chassis. All trimmer adjustments are for the high frequency ends of the bands and are located in the sides of the coil shield cans. The Broadcast band trimmer is the uppermost one in each case. All padder adjustments are for the low frequency ends of the bands and are located on the rear apron of the chassis. The padder for the Broadcast band is the uppermost one.
Place band switch in the middle or BC position. Set generator to 1400 kc. and adjust the oscillator trimmer to receive the signal at the proper calibration on the receiver dial. Adjust the " BC " RF and ANT trimmers for maximum signal. Re-set generator and receiver to 600 kc, and adjust padder condenser C8-1 for proper calibration or maximum signal. If it should prove necessary to change the adjustment of padder C8-1 to any appreciable extent, it may also be necessary to re-adjust the oscillator trimmer condenser for exact calibration at the high frequency end of the band.
SHORT WAVE BROADCAST BAND.
Place band switch in the clockwise or " SW " position. Set generator and receiver dial to 15 Mc. and adjust oscillator trimmer for proper calibration. (More than one signal may be heard as the trimmer condenser is rotated. At least two major signals will be observed. The proper signal will be the one tuned nearest maximum anti-clockwise rotation of the trimmer condenser.) Re-set receiver and signal generator to approximately 13 Mc. and adjust " SW " RF and ANT trimmers for maximum signal. (Again more than one position of the trimmers may result in maximum signal. The one nearest maximum clockwise rotation is the correct one.) Re-set signal generator to 6 Mc. and adjust padder condenser 08-2 for maximum signal.
The receiver should be used with as short an antenna as may be practical under the particular conditions of use. An antenna length of 6 to 15 feet is recommended for average conditions.
PHONO OR TUNER
To use the HE - 621 receiver as a tuner to feed a public address amplifier etc., output may be obtained from the jack farthest from the antenna-ground strip on the rear apron of the receiver. An amplifier of high impedance Input should be used. To use the HE - 621'as an amplifier for use with a record player turntable and pickup, the output of the pickup (which should be of the high impedance type) may be plugged into the jack nearest the antenne-ground strip on the rear apron of the chassis. The band change switch should be turned to its extreme counterclockwise or " PHONO " position