Philips N4520 - Philips N4522 Specifics; Layout Panel 1 N4522

www.reeltoreel.nl Philip van der Matten ver 4.0 | 24 apr 2024 | page 9/11
Calibrating N4520, short summary (always have the Service Manual at hand for the full instructions)
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1 - section 3.2 impossible to perform (zero-setting peaklevel and VU meters).
2 - azimuth playback head. screw C.
3 - azimuth record head, insert conn. J into L, and conn. I into K. Adjust screw C rec head. reseat conn. (section 7)
4 - play ref tape 250 nWb/m – 0 dB section, line out: 780 mV. adjust R(1)27.
5 - play freq char. section, line output: make 1 kHz equivalent to 16 kHz ±1,5 dB. 1 kHz=ref.point. adjust R(1)57.
6 - record 9,5 cm/s BU5 (3,5) 330 Hz 1 V in. line out: 1 V ±0,25 dB. note LINE LEVEL position – LEAVE IT!
7 - record BU5 (3,5) 1 kHz 80 mV, 16 kHz 80 mV in. line out: 1 kHz=16 kHz ±2 dB. adjust R(1)36 bias.
8 - record freq sweep 31 Hz-16 kHz. line out: ±2 dB. 1 kHz=ref.point 0 dB
9 - record 330 Hz, adjust input signal so line out=1.41 V (meters +3 dB). distortion <3%. adjust R(1)36. repeat sweep.
10 - record BU5 (3,5) 330 Hz 1,41 V. line out: 1,41 V ±0,25 dB. adjust R(1)25 rec current.
11 - record 19 cm/s(!) BU5 (3,5) 1 kHz 80 mV, 20 kHz 80 mV in. line out: 1 kHz=20 kHz ±2 dB. R41 bias 19cm.
12 - record freq sweep 31 Hz-20 kHz(!). line out: ±2 dB. 1 kHz=ref.point 0 dB
13 - record 330 Hz, adjust input signal so line out=1.41V (meters +3dB). distortion <3%. adjust R41. repeat sweep.
14 - record 38 cm/s(!) BU5 (3,5) 1 kHz 80 mV, 26 kHz(!) 80 mV in. line out: 1 kHz=26 kHz ±2 dB. R40 bias 38 cm.
15 - record freq sweep 31 Hz-26 kHz(!). line out: ± 2dB. 1 kHz=ref.point 0 dB
16 - record 330 Hz, adjust input signal so line out=1.41 V (meters +3 dB). distortion <3%. adjust R40. repeat sweep.
BU104
(R)
BU4
(L)
BU106
(R)
BU6
(L)
2
4
1
6
7
5
3
R45
(L)
R145
(R)
R125
(R)
R25
(L)
Rec current
Line out
Line outLine in
Headphone Amp. (3A)
Headphone Amp. (3A)
Rec./PB. Amp. (2B)
Rec./PB. Amp. (2B)
Rec./PB. Amp. (2B)
Rec./PB. Amp. (2B)
Pre-amp (3B)
Pre-amp (3B)
R L
R36 (L)
R136 (R)
Bias 9,5 cm/s
Bias
R41
bias 19
cm/s
R40
bias 38
cm/s
Playback level
R27 (L)
R127
(R)
16 kHz 9,5 cm
Freq. characteristic
R157
(R)
R57 (L)
BU 5
Layout panel 1 Philips N4522
Oscillator (2C)
Oscillator (2C)
Philip van der Matten
www.reeltoreel.nl
J
I
L
K
r
e
c
/
p
b
h
e
a
d
A
B
C
Head assembly
screws
conn.
Head layout
N
O
T
C
O
R
R
E
C
T
Y
E
T
!
!