User manual MCINTOSH MX135 SERVICE MANUAL B

[. . . ] 3 Section Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 - 70 Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Use only replacement parts recommended by the manufacturer. REAR PANEL 3 SECTION LOCATIONS TOP VIEW WITH COVER REMOVED BOTTOM VIEW WITH COVER REMOVED 4 MX135 BLOCK DIAGRAM 5 6 BLOCK DIAGRAM con't 7 8 1 INTERCONNECT MX135 9 10 11 2AC B DISPLAY 050036 SH 1 OF 2 12 13 14 MX135 2AC B DISPLAY 050036 SH 2 0F 2 15 16 17 2A DISPLAY CONTROL SECTION 050036 3 SURROUND 050037 SH 1 OF 6 2B LED SECTION 050054 2C KEYBOARD SECTION 050053 18 19 20 MX135 3 SURROUND 050037 SH 2 OF 6 21 22 23 3 SURROUND 050037 SH 3 OF 6 24 25 26 MX135 3 SURROUND 050037 SECTION 4 OF 6 27 28 3 SURROUND 050037 SH 5 OF 6 29 30 MX135 3 SURROUND 050037 SH 6 OF 6 31 32 3 SURROUND 050037 33 34 MX135 NOTES 35 36 4 DATA 050033 SH 1 OF 2 37 38 MX135 4 DATA 050033 SH 2 OF 2 39 40 41 5 S-VIDEO 050035 SH 1 OF 2 42 43 44 MX135 5 S-VIDEO 050035 SH 2 OF 2 45 46 47 6 VIDEO 050034 48 49 50 MX135 7 INPUT 050032 SH 1 OF 2 51 52 53 7 INPUT 050032 SH 2 OF 2 7 INPUT 050163 54 55 56 MX135 8 COMPONENT VIDEO 050039 57 58 59 TUNER ALIGNMENT PROCEDURE Note: Refer to Figure 1 while reading the below procedure. FM ALIGNMENT PROCEDURE 1. Tune to 108. 5MHz and adjust C59 (FM OSC Trimmer Capacitor) for 24. 5VDC at R46. Repeat steps 4, 5 and 6 as necessary for a tuning range of 3. 5VDC to 24. 5VDC at R46. Tune the Generator and Tuner to 90MHz and adjust Coils: L2 (FM MIX), L3 (FM RF) and L4 (FM ANT) for best sensitivity. Tune the Generator and Tuner to 104MHz and adjust Trimmer Capacitors: C60 (FM MIX), C62 (FM RF) and C63 (FM ANT) for best sensitivity. Tune Tuner to 90MHz with no RF Input and adjust T9 (FM DETector Primary) for zero volts between TP1 and TP2 relative (connector J6). Tune the Generator to 90MHz and adjust the RF Output to 1000uV and 100% MONO modulation at 1000Hz. Reduce the Generator Output to minimum and detune the Generator so the Receiver picks up only noise, then recheck the voltage between TP1 and TP2 (connector J6). If it is not 0+/0. 2VDC, repeat steps 11 and 12. If there is interference from a station on this frequency, tune the Tuner to a nearby frequency free from interference for this measurement. Then switch the Generator to stereo (left only) and adjust T10 (FM IF Transformer) for the lowest distortion at the TUNER IN/OUT RCA jacks. Switch the Analyzer to the right channel TUNER IN/OUT jack and adjust R71 (MPX SEParation Pot) for best separation (minimum output). Switch the Generator to the Right Channel and the Analyzer to the Left Channel. Adjust R71 (MPX SEParation Pot) and check for best separation (minimum output). Reduce the generator output to 5uV and adjust R73 (STEREO SWITCH Pot) so the MPX light (Dot next to Signal Strength number) just comes on. AM ALIGNMENT PROCEDURE 1. [. . . ] Note the initial position of R70, and then adjust R70 fully counter clockwise. Tune the Generator and Tuner to 1400kHz (20uV, 30% modulation), then Adjust T7 (AM IF) for maximum signal. Slowly adjust R70 clockwise until the MX135 front panel signal strength display reads "9". [. . . ]