Scully 280B Series - Page 197

Model 285B
Electronics Maintenance
6.15
Level and Equalization
6.16 Install 250 nWb/m alignment tape for 7.5-15 in/s full track and
2-channel 2 track. Install 200 nWb/m alignment tape for all other
LepLoducer tape speeds and track-channel configurations. Connect ACVM
to LINE OUTPUT connectors. Remove head cover. Adjust level and then
equalization in accordance with the following chart (see Figure 6-3
and inside head cover for location of adjustments).
CHANNEL NO. FREQUENCY
ADJUST
FOR
1
High Speed
1 kHz
LEVEL CH
1 +4 dBm
2
High Speed 1 kHz LEVEL
CH
2
+4 dBm
1
High Speed 10
kHz HI CH 1
+4
dBm
2 High Speed
10 kHz HI CH 2 +4 dBm
1 Low Speed 10 kHz LO
CH 1 +4 dBm
2 Low Speed 10 kHz LO CH 2
+4
dBm
6.17
Signal-to-Noise, LINE OUTPUT
6.18
Connect LINE OUTPUT CHAN 1 to ASA-A weighted filter and the
filter to the ACVM. Install a bulk-degaussed roll of tape on the
machine. Press START pushbutton. The ACVM should indicate a maximum
level indicated below after correcting for the insertion loss of the
filter (reference 500 nWb/m).
TAPE SPEED FULL TRACK 2 TRACK
4 TRACK
3.75 68 dB 64 dB 61 dB
7 .5
72 dB 68 dB 65 dB
15.0
72 dB
68
dB
65 dB
6.19 Noise Level, SPEAKER OUTPUT
6.20
With ACVM and filter connected as ln step 6-18, install the
8-ohm load resistor across SPEAKER OUTPUT CHAN 1. Set VOLUME control
6-5