Module Performance Check Of Exciter Unit - Sailor RE2100 Technical Manual

3 SERVICE
3.6.4

MODULE PERFORMANCE CHECK OF EXCITER UNIT

This chapter contains the following sections:
3.6.4.1. Check of Compressor and AF Limiter
3.6.4.2. Check of Carrier Limiter Amplifier
3.6.4.3. Check of Modulator
3.6.4.4. Check of SSB Filter
3.6.4.5. Check of RF Limiter and Carrier Insertion
3.6.4.6. Check of Step Attenuator
3.6.4.7. Check of 70 MHz IF and LO Injection
Any value, which differs too much from the values given in this chapter should lead to an adjustment of
the circuit in question. Please, see chapter 3.7.3. ADJUSTMENT PROCEDURE FOR EXCITER UNIT
How to select service programmes is described in the chapter 3.10.
3.6.4.1 CHECK OF COMPRESSOR AND AF LIMITER
1. Connect a tone generator (1000 Hz) to the testbox at the BNC-socket "AF to TX". If a testbox is
not available, connect the tone generator directly to the handset plug on the RE2100 (to J03-2, pin
4). Connect it with a capacitor 22 uF/25V because of the DC voltage on the microphone terminal
2. Connect a scope probe to Q04-4 emitter (TP1-4).
3. Select service programme SP-05-1 and select J3E mode.
4. Adjust the tone generator output voltage from a minimum until the level at the scope is just constant.
This limitation must happen at approx. 0.1Vpp measured at the handset plug J03-2, pin 4.
5. Check that the voltage at Q04-4 (TP1-4) stays approx. at the same level when increasing the tone
generator 20 dB to 1Vpp.
6. Select service programme SP-05-0.
7. Connect scope probe to R07-4 and read approx. 0.5 Vpp (tune tones).
8. Connect scope probe to Q04-4 emitter (TP1-4).
9. Connect R34-4 (TP7-4) to ground (chassis). That is a short-circuit of R34-4, which means that the
signal exceeds the cutting level.
10. Adjust the scope to full deflection (8 div).
11. Disconnect the grounding of R34-3 and read the peak-peak deflection to 6.9 div. +/- 0.3 div.
3.6.4.2 CHECK OF CARRIER LIMITER AMPLIFIER
1. Select service programme SP-05-0 and press handset key.
2. Connect a scope probe to J01-4 and measure the carrier injection to approx. 0.1Vpp.
3. Connect scope probe to the connection between R93-4 and C75-4 (TP2-4) and read the voltage
to 1,55Vpp +/-0.1V.
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RE2100