TM 11-625-2872-14&P

SECTION II INSTALLATION

2-1. PORTABLE CASE OR RACK MOUNTING.

2-2. The 8808A is operated as a self-contained instrument using an 860-500 Power Supply to furnish operating power for the preamplifier. The preamplifier power supply combination operates on a 115/230 volt 50 or 60 Hz power line. See the power supply Operating and Service Manual, IM-860-500-3.

2-3. The preamplifier power supply combination can be mounted in the 860-1400 Case for single channel benchtop operation. For two channel operation, two preamplifiers and power supplies mount in an 860-200 Module, for benchtop or rack mounting.

2-4. When the 8808A is operated with the 860-500 Power Supply, preamplifier input and output signal connections are made on the rear panel of the power supply as follows:

Signal Input Jack J3:

Plus (+) signal pin A

 

Signal ground pin B

 

Mating connector is 10G3-34FW

Signal Output Jack J2:

Plus (+) signal pin A

 

Signal ground pin E

 

Mating connector is 10B9-5MW

For monitoring, connect the preamplifier output signal to a voltmeter, oscilloscope, or other voltage indicating instrument which has a signal range of 0 to +5 volts or 2.5 volts. The output signal can be recorded using a strip chart recorder, magnetic tape recorder, or other instrument which will operate with an input of 0 to +5 volts, or ± 2. 5 volts.

2-5. INSTALLATION IN SANBORN RECORDING SYSTEMS.

2-6. The 8808A can be installed in Sanborn Recording Systems 7701A, 7702A, 7704A, 7706A, 7708A, for 1, 2, 4, 6, or 8 channels of recording using the heated stylus recording technique. Operating power for the preamplifier is supplied by the recording system. See the recording system instruction manual for installation information.

2-7. The 7701A Recorder is supplied in a portable case. The 7702A Recorder is supplied either in a mobile cart, or for rack mounting. The 7706A, 7708A Recorders are rack mounted.

SECTION III OPERATION

3-1. OPERATING CONTROLS.

3-2. RANGE switch selects the bottom scale signal level. Scale is calibrated in dBV (decibels referred to a 1 volt rrns signal). Full scale signal for 50 Db span operation is 50 dB above bottom scale signal. For 100 dB span, full scale signal is 100 dB above bottom scale signal. Bottom scale and corresponding full scale signal levels for each setting of the RANGE switch are given in Table 3-1.

3-3. DB SPAN switch selects either 50 dB or 100 dB maximum span between the bottom scale and full scale input signal levels.

NOTE

On the 100 dB span, only the - 50, -60, -70, -80 RANGE switch positions are used.

Switch also indicates recorder calibration: 1 dB/div for 50 dB span. 2 dB/div for 100 dB span.

50 DB SPAN

 

 

 

 

Range

 

 

 

 

Switch

 

Bottom Scale

 

Full Scale

Setting

dBV

Volts rms

dBV

Volts rms

0

0

1 V

+50

316 V

-10

-10

.316V

+40

100 V

-20

-20

.100V

+30

31.6 V

-30

-30

31.6 mnV

+20

10 V

-40

-40

10 mV

+10

3.16 V

-50

-50

3.16 mV

0

1 V

-60

-60

1 mV

-10

.316 V

-70

-70

316 μV

-20

.1 V

-80

-80

100 μV

-30

31.6 mV

100 DB SPAN

 

 

 

 

-50

-50

3.16 mV

+50

316 V

-60

-60

1 mV

+40

100 V

-70

-70

316 μV

+30

31.6 V

-80

-80

100 μV

+20

10 V

Table 3-1. Bottom and Full Scale Signal Levels

-3-