Marantz 3800 Service Manual

Page 2

maranil®

MODEL 3800

SERVICE MANUAL

MARANTZ CO., INC. 20525 NORDHOFF STREET, CHATSWORTH, CALIFORNIA 91311
A WHOLLY OWNED SUBSIDIARY OF SUPERSCOPE INC., CHATSWORTH, CALIFORNIA 91311

Page 26

-10 dB

-20 dB

-30 dB

(3)

(c)

(d)

(e)

Hz 50 100 200

for 0 VU indication on the Dolby
VU Meter (corresponds to 6.3 V rms
at PREAMP OUTPUT Jack).

Check frequency response at oscil-
lator frequencies from 20 Hz to 15
kHz. Response should be flat (:
1.5 dB).

Reset oscillator frequency to 5 kHz
and observe the output level. Level
should drop 9 dB (1 2 dB) or to an
output level between 56 mV and
70 mV rrns.

Reset oscillator lrequency to 100 Hz
and lower the signal level by 30 dB
and lower the signal level by 30 dB to
an output of approximately 200 mV
rms as measured at the PREAMP
OUTPUT Jack.

For encode/decode back-to~back frequen-
cy response:

(al

Ensure all controls except Dolby

500

2000 5000 l 0000 20000

Figure 2-9 Dolby Frequency Response, Encode Made

(bl

(n)

(d)

(e)

(fl

Switch and RECORD LEVEL Con»
trols are set, as listed in Paragraph 3D.
Reset DOLBY Switch to REC |,and
turn RECORD LEVEL Controls fu lly
clockwise.

Apply a 100 Hz signal to AUX
INPUT Jack and adjust the amplitude
for 580 mV rms as measured atthe
TAPE l OUTPUT Jack.

Connect a short patch cord (RCA
phono plug on both ends) between

the TAPE l INPUT and the TAPE 2
OUTPUT Jacks.

Reset the TAPE MONITOR Switch
to TAPE | and adjust the PLAY CAL
Controls for O VU indication onthe
Dolby VU Meter.

Observe output at PREAMP GUT-
PUT Jack for a measuremeni of
approximately 6.3V.
Check frequency response at oscil-
lator frequencies from 20 Hz to 15
kHz. Response should be flat (i
2dBl.

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