Megard HE-621 Schematic

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E' sc1-1EMAT|c D1AG RAM - Ho vwooo E\_EcTR0N1cs - MODEL ME-621
Ant 111.1 me TA? vas 105
? 2552 Amt = 2552 n F = 2532-1 IF = 2532-4 :F = 94-500
1 3 oil' EG 1 ; icy -fl' 'q' R10 `[' I R15 T
CAPAC"?R? RESSTORS Fora A-c oPE1=1AT1oN. 5115 1;/ur *U
No. o.rAcrrY TYPE voL1AGz N01 onms wfnmse _ _ '
, . PAPER 600 7,000 56
g PAPER 600 g 41,500 li
6 .05 MFD. PAPER 600 6 1,000,W0 H
11 .05 MFD, PAPER % 'gg 53 \ I '
19 Wu Mml mm % ?3 szgmlaag 1o1~1sc?>~r1zo1 FOR D-c oPERAT|oN pg
? 1% QQ ,EQ }% 22 7? 3 AND NE<;AT|vs 'ro P111 5. Q , 7? ' .

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PAGE 15-2 ME A D
T- Ava 5 BT 5 Cf
1 F T ' R13 li Ave 3,1
(C).fohn F. Rider

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- Lia
" sung
indicated on the diagram to
(C)John F. Rider

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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 stator connection of the tuning condenser
section cz RF or to the RF input grid (socket connection #6) of the 7s8 tube.
If there is no blocking condenser ln the output lead of the signal generator,
the lead should be connected through a .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
M55 Kc. 30% modulated signal output.
generator for
Now adjust the condensers on IF transformers 2532-1 and 2532-A 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 coll leads of the speaker. When making the
to the IF tuning condensers, it is advisable to use as low
level as possible.
Replace the .1 Mfd. condenser in series with the generator
ohm resistor. Connect the generator to the terminal marked
antenna-ground strip which is mounted on the rear apron of
trimmer adjustments are for the high frequency ends of the
final adjustments
an input signal
lead with a hoo
"A" on the
the chassis. All
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 ln the middle or BC position. Set generator to IAOO Kc. and
the signal at the proper calibration
and ANT trimmers for maximum signal.
and adjust padder condenser C8-1 for
it should prove necessary to change
adjust the oscillator trimmer to receive
on the receiver dial. Adjust the "BC" RF
Re-set generator and receiver to Soo Kc.
proper calibration or maximum signal. If
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.
Place band switch in the clockwise or "SW" position. Set generator and receiver
dlnl to li 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 lp
maximum signal. The one nearest maximum clockwise rotation is the correct one.)
Re-set signal generator to 6 Mc. and adjust padder condenser C8-2 for maximum
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 i5 feet is
recommended for average conditions.
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
gn thedrear apron of the receiver. An amplifier of high impedance Input should
e use .
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 antenna-ground strip on the rear
apron of the chassis. The band change switch should be turned to its extreme
counterclockwise or "PHONO" position
(C)John F. Rider

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