Program b to right headphone, Program to speaker, Ifb test – Telex MCE325 User Manual

Page 46: Ifb b, Ifb test -8, Ifb b -8

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4-8

C S I - 2 0 0 U s e r I n s t r u c t i o n s

11

Restore jumper J16 to short pins 1 & 2.

Program B to Right Headphone

1

Remove the signal from the PROGRAM A input, and connect it to the PROGRAM B input.

2

Measure the level at the right headphone output (J2, 3 & 5). It should be 1.3 dBu ±2 dBu.
(Program volume at maximum.)

3

Set the signal generator to 0 dBu, 100 Hz. The right headphone output should be 0.8 dBu ±2
dBu.

4

Set the signal generator to 0 dBu, 10 kHz. The right headphone output should be –3.8 dBu ±2
dBu.

5

Reset the generator to 0 dBu, 1 kHz.

6

Remove jumper J17 (program not assigned to right headphone). Verify that the signal level
drops at least 35 dB from the reference level in step 2.

7

Restore jumper J17 to short pins 1 & 2.

Program to Speaker

1

Connect the AC voltmeter across the 8 ohm load at the speaker output

2

Set the SPKR ON button to the on position.

3

Measure the level at he speaker output. It should be 6 dBu ±2 dBu. (Program volume at
maximum.)

4

Set the signal generator to 0 dBu, 100 Hz. The speaker output should be 1.3 dBu ±2 dBu.

5

Set the signal generator to 0 dBu, 10 kHz. The speaker output should be 7.3 dBu ±2 dBu.

6

Reset the generator to 0 dBu, 1 kHz.

7

Remove jumper J18 (program not assigned to speaker). Verify that the signal level drops at
least 35 dB from the reference level in step 3.

8

Restore jumper J18 to short pins 1 & 2.

IFB Test

IFB B

1

Set all front panel buttons to off. Set all volume controls to minimum.

2

Move the J5 jumper to short pins 1 and 2 (IFB B assigned to channel 4).

3

Check the output level across intercom channel 4. It should be –9.8 dBu ±2 dBu.

4

Turn on the CH 4 TALK and MIC ON buttons. The channel 4 output should drop at least 45
dB from the reference level in step 3.

5

Turn off the CH 4 TALK and MIC ON buttons.

6

Ground the Key 4 input (short J22 pin 20 to pin 10). The channel 4 output should drop at least
45 dB from the reference level in step 3.

7

Remove the Key 4 ground.

8

Move the J5 jumper to short pins 2 and 3.

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