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| b. Optical Preamplifier Adjustments |
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Step | Action | Indication |
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No. |
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4 | Cat. No. |
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240A |
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Proj. 1
GAIN Lt
hf
GAIN
Rt
hf
Lt tp
Lt
signal
present
Rt
Rt tp
GAIN Lt
hf
GAIN Rt
hf
Proj. 2 gnd
5
format
01Mono
format
01Mono
6
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| RTA |
Cat. No. 240A |
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| IN |
Proj. 1 | Status |
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RV101 | Gain | L |
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RV102 hf |
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RV201 | Gain | R |
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RV202 hf |
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TP501 L tp |
| X | |
| L | SIGNAL |
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| PRESENT | Y |
| R |
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TP502 R tp |
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RV301 Gain | L |
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RV302 hf | R |
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RV401 Gain | SCOPE | ||
RV402 hf |
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Proj. 2 | Status |
| DUAL TRACE |
TP503 GND |
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| MODE | ||
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NOTE: Be sure that the vertical range is set the same on both channels.
b. Optical Preamplifier Adjustments
Notes
On the Cat. No. 240A Optical Preamplifier Card
Turn all of the Proj 1 and Proj 2 hf potentiometers fully counterclockwise (CCW).
Verify that power to the power amplifiers is OFF.
Press the Mono 01 format switch on the front panel; the LED in the switch should light.
Connect the RTA and the oscilloscope to the Cat. No. 240A TP501 L (left) and TP502 R (right) test points as shown in the interconnection diagram. Switch the scope to dual trace mode.
Earth (ground) both instruments at TP503 GND on the card.
The input to the RTA will be switched to the left channel or right channel in the following steps.
