Sennheiser HEV 70 - Test and Alignment Instructions

HEV 70
03 / 94 – 9
NOTES:
No. Measurement,
adjustment
Signal input Preparations, settings Test point Desired value Adjuster Remarks
1 Current
consumption
AF signal generator to
J1 (R and L channel):
200 mVeff / 1 kHz
Switch S1 "ON"
volume control
R104.1 and R104.2 "cw";
DC ammeter
Input
current
210 - 230 mA
(minimum)
R128 LED D29 "red"
1.1 Operating voltage as 1. as 1.;
DC voltmeter
TP1 24 - 28 VDC
2 Reference voltage as 1. as 1.;
DC voltmeter
MP1 5.1 VDC
3 Converter
frequency
as 1. as 2.;
Oscilloscope
MP2 > 60 kHz please see
pattern on
page 7
4 Operating voltage
+ 600 V
as 1. as 2.;
DC voltmeter
MP3 580 - 600 VDC
4.1 Operating voltage
+ 10 V
as 1. as 2.;
DC voltmeter
MP4 10 VDC
4.2 Operating voltage
– 10 V
as 1. as 2.;
DC voltmeter
MP5 – 10 VDC
4.3 Output stage
bias voltage
as 1. as 2.;
DC voltmeter
MP6 (+R)
MP7 (–R)
MP8 (–L)
MP9 (+L)
300 ± 15 VDC
5 Polarisation
voltage
as 1. as 2.;
DC voltmeter
MP10 255 VDC
6 AF amplifier as 1. as 2.;
UPM 550 - 1 and
Oscilloscope
MP11 (R)
MP12 (L)
190 - 200 mVeff
6.1 AF amplifier as 1. as 2.;
UPM 550 - 1 and
Oscilloscope
MP13 (R)
MP14 (L)
190 - 200 mVeff
6.2 Output voltage if outputs are clipping
decrease AF signal
generator voltage
down to 180 mVeff
as 2.;
UPM 550 - 1 and
Oscilloscope
MP15 (+R)
MP16 (–R)
MP17 (–L)
MP18 (+L)
180 - 200 Veff Output voltage
is not clipping
7 THD as 6.2. as 2.;
UPM 550 - 1 and
Oscilloscope
MP15 (+R)
MP16 (–R)
MP17 (–L)
MP18 (+L)
k < 0.3 %
8 Frequency
response
AF signal generator:
60 mVeff / 1 kHz
as 2.;
set indicated value to
reference level, adjust
UPM 550 - 1 to 0 dB
(Uncal. - Adjuster)
MP15 (+R)
MP16 (–R)
MP17 (–L)
MP18 (+L)
U = 0 dB LED D29
"green"
8.1 Frequency
response
Check frequency
response with
AF signal generator
from 20 Hz to 20 kHz
MP15 (+R)
MP16 (–R)
MP17 (–L)
MP18 (+L)
– 2 ... 0 dB
6. TEST AND ALIGNMENT INSTRUCTIONS
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