Teac A-550RX - Page 12

A-SSORX
5-6 DBX PCB ASSEMBL
5-6-1 CONNECTION
Low distortion
AF OSCILLATOR
Distortion factor 0.02% or less
Y CHECKS
ATTENUATOR
TP3L
(TP3R)
TRAIL TP2L
{TPIR)
BBX PCB
Term. 4 (2)
Term. #3 (12) = GND
NOTE:
the following:
#5-3, ITEM 2, 2nd
#5-5, ITEM 13
#5-5, ITEM 14
AC VOLTMETER
DISTORTION METER
If checks in this section are conducted, re-adjust
OSCILLOSCOPE
TA-1100
NOTE: L-ch (R-ch)
Fig. 5-7
5-6-2 DECODING CHECKS
Check in the play mode without loading tape, and with NR SYSTEM switch in OUT position.
ADJUST MEASURING
STEP SIGNAL SOURCE (or CHECK) POINT RESULT REMARKS
(on DBX PCB)
1 kH2z/—26.5 dB
1 (36.7 mV} VR101/VR201 TPIL/TPIR —2.5 dB (580-mV)
j—___}___—
——_—.
ee
eee
ne
One
oo
: @® RMS SYM adj.
2 eee VR104/VR204 TP3L/TP3R ee ea @ «1: 100 Hz x 2
; p © Refer Fig’s 58 & 5-9
. 0.41 mV +1 dB (0.365 mv ~
3 100 Hz/—32 dB Check 0.460 mv)
4 1 kHz/—32 dB VR106/VR206 TP2L/TP2R —8 dB(308 mV)
, @VCA SYM adj.
5 Pi ea oe VR102/VR202 (on isabel aeniake Pa nina setmenie
(13.8 mV) nie gaa SSRORTLON fundamental (1 kHz)
ese ® Refer Fig’s 5-10 & 5-11
Min. distortion factor
6 1 kHz/—35 dB Check (0.1% or less)
1 kHz/—30 dB - Ciean 3 kHz sine-wave (#2) (on @ EM adj.
f (24.5 mV) VR103/VR203 ‘scope thru distortion meter) @ Refer Fig’s 5-10 & 5-11
+ —
Min. distortion factor
8 1 kHz/—30 dB Check (0.1% or less)
9 Repeat steps 4 through 8 until the best result is gotton.
1 kHz/—32 dB
10 (19.5 mV) VR106/VR206 TP2L/TP2R —8 dB (308 mV) Ref. 1
11 100 Hz/—32 dB Check [ " —1 dB £1 dB varies from ref. 1
12 10 kHz/—32 dB " " +9.4 dB +1 GB varies from ref. 1
43 1 kHz/—62 dB , 7 —68 dB +1 dB
(615 UV) (275 pV ~ 346 BV)
Sie
ode
+12dB
£1
dB
(2.75
V~3.46
V)
14 " " and
(61.5 mV) | 0.8% or less distortion
1 kHz/—82 dB . 5 a
15 (61.5 LV) 90 dB (24.5 UV) or more |
12