Kenwood TS-990S Service Manual

Also see for SP-990: Instruction manual

Contents

TS-990S22Fig. 21 1st mixer of the SRX-2 path+14V1st IF73.095MHzRF Q401Q402Q403Q404VR401L403L406SLO173.120~133.095MHzL404CIRCUIT DESCRIPTION4-6. MCF AdjustmentTwo types of MCFs are prepared for the SRX-1 path (atan IF frequency of 11.374MHz) and SRX-2 path (at an IFfrequency of 73.095MHz).The SRX-1 path MCF (XF351) is a filter that consists ofa 2-pole MCF with a center frequency of 11.374MHz and apassband width of 6kHz. Since the XF351 termination im-pedance is 1 k, the impedance is converted using variableinductors (L368 and L369).Connect an appropriate equipment, such as a trackinggenerator, to the MCF adjustment connectors (CN360 andCN370) and turn the variable inductors (L368 and L369) toadjust the MCF.Make the MCF adjustments in adjustment mode, variableinductors (L368 and L369), or TX-RX unit (X57-827 A/2).The SRX-2 path MCF (XF401) is a filter that consists ofa 2-pole MCF with a center frequency of 73.095MHz anda passband width of 15kHz. Since the XF401 terminationimpedance is 2.5 k, the impedance is converted using vari-able inductors (L406, L417, L418, and L419).Connect an appropriate equipment, such as a trackinggenerator, to the MCF adjustment connectors (CN460 andCN470) and turn the variable inductors (L406, L417, L418,and L419) to adjust the MCF. If you have replaced the MCF(XF401), variable inductors (L406, L417, L418, and L419),or TX-RX unit (X57-827 A/2) make the MCF adjustments inadjustment mode.Fig. 22 The MCF circuit of the SRX-1 pathFig. 23 The MCF circuit of the SRX-2 pathFromSub RX 1st Mixer 273.095MHzCN460L417+8VL406Tune connector Scope unit (X42-343 A/10)ToSub 2nd Mixer73.095MHzXF401CN470L419L418+8VQ408Sub 1st IF AMP 1Tune connector16dBFrom Sub RX 1st Mixer 111.374MHzXF351CN360 CN370L368 L369Tune connector Tune connectorTo Sub 2nd IF AMP 111.374MHz