Harman kardon 75 plus service manual

Page 1

The Harman-Kardon
Model 75 +

AM [Stereo FM
Multichannel Receiver

Technical Manual

harman / kardon

Page 2

ALIGNMENT PROCEDURES

FM IF 8t RF ALIGNMENT
INSTRUMENTS:

FM S.S.G., modulator with 400Hz at 100%. V.T.V.M., Oscilloscope, and Distortion Meter.

NOTE: Set TONE control to flat response (or mechanical center of both of BASS control and TREBLE control)
Set FUNCTION selector to FM.

Step SIGNAL SOURCE OUTPUT METER ADJUST ADJUST FOR
1 Check mechanical zero center of TUNING indicator, M101 at POWER switch OFF. Adjust it if necessary.
None IFM ANTENNA TUNING indicator, Zero or center indication ON
2 terminals opened). Tuning connect oscil|oscope TOP adjuster of T101 TUNING indicator MIOI
control at no signal. and V.T.V.M. to (or RAT CAN) observing noise output with
TAPE OUT. output meter.
3 Same as above. Same as above. Bottom adjuster of T101, Maximum noise output on
V.T.V,M.
4 Same as above. Same as above. TOP and bottom ad- Same as above.
justers of IF' in
FRONT-END
5 Connect SSG to FM ANT
terminal, with no signal Same as above. Fieadjust TOP adjuster Zero or center indication ON
(or $86 OFF).Tuning of T101. TUNING indicator, M101.
control at no signal.
6 Set 586 output to 88MH2, Same as above, L0, LR and LA in Maximum noise output on
Tune radio to 88MHz of FRONTVEND. V.T.V.M.
886.
7 Set SSG output to 106M H2, Same as above. TCO, TCR and TCA in Same as above.
and tune radio to 106MHz. FRONTAEND.
8 Repeat step 6 and 7 Ior best sensitivity.
9 Use very weak signals of Same as above. LA and LR. Zero or center indication of
SSMHZ. TUNING indicator M101.
Tune radio to 88MH1.
10 Use very weak signals of Same as above. TCA and TOR. Same as above.
106MHz. Tune radio to
106MHz.
11 Repeat step 3 through 5 for best setting under 886 connected but no signal.
Use 98MHZ. 1mV signals Minimum harmonic distortion
from SSG modulated with Connect distortion Bottom adjuster of on distortion meter keeping
12 400H2 at 100%. Tune radio meter, V.T.VJVL and T101. noise output to 3V on
to QSMHZ. (Note: If oscilloscope to V,T.V.M. (adjust VOLUME
another signal exists, SPEAKER out. CONTROL VR301 through
shift to quiet point) VFiBOl, if necessary).

Observe output waveform with oscilloscope at S/N = 20 to

SOdE.

Observed waveform will be (1 l, (2) or (3), below:

(1) / NOISE (2) (3)

MODU-
LATING
FREQ.
400Hz.
13 Same as above. Same as above. UNACCEPTABLE UNACCEPTABLE ACCEPTABLE

Wave form Ill and (2) will result from misalignment.

(1) To correct, carefully adjust two adjusters of IF on the
FRONT-END and bottom adjuster of T101.

(2) Check TUNING meter zero center again under no signals
of SSG. If necessary, adjust the Zero point with TOP
adjuster of T101.

(3) For ANTENNA input of 1mV from 586, distortion shall
be adJUSted with bottom adjuster of T101, if, necessary.