MARANTZ SR4000
Manual de Servicio

8-3

8-3

Test 13a : Select track 5 : For 1 kHz in Center channel and measure the crosstalk in Left, Right, Surround. Requirement : < -25 dB Test 14a : Select track 6 : For 1 kHz in Surround channel and measure the crosstalk in Left, Center, Right. Requirement : < -25 dB 2- Centre mode �normal� (use 3 kHz or 1 kHz tone) Test 11b : Select track 3 : For 3 kHz in Left channel and measure the crosstalk in Center, Right, Surround Requirement : < -25 dB Test 12b : Select track 4 : For 3 kHz in Right channel and measure the crosstalk in Surround, Left, Center Requirement : < -25 dB Test 13b : Select track 5 : For 3 kHz in Centre channel and measure the crosstalk in Left, Right, Surround Requirement : < -25 dB Test 14b : Select track 6 : For 1 kHz in Surround channel and measure the crosstalk in Left, Center, Right Requirement : < -25 dB Inputs overload test (headroom to visible clipping) General : Before starting these tests set Master Volume -15 dB lower to make a new output reference (1W on loudresistors). Requirement : check on scope for no visible signal clipping or measure THD <1,5 % Test 15 : Select track 7 : Check the Left output signal between 20 Hz ... 20 kHz Test 16 : Select track 8 : Check the Right output signal between 20 Hz ... 20 kHz Test 17 : Select track 9 : Check the Center output signal CENTER �SMALL� between 100 Hz ... 20 kHz CENTER �LARGE� between 20 Hz ... 20 kHz Test 18 : Select track 11 : Check the Surround output signal between 50 Hz ... 7 kHz Test 19 :Center Mode Check Select Center size �SMALL�. a - Select track 5 at 1 kHz : Adjust the Center output again with master volume for 1W output as 0 dB reference. b - Select on track 5 the 100 Hz : Signal to check the roll-off behaviour at -3 dB on the Center output c - Select on track 5 the 50 Hz : Signal and measure on the Left and Right output channels. The lost 50 Hz signal on the Center output is equally splitted and added to the L and R channels. Test 20 : Center Mode Check Select Center size �LARGE� Repeat test 19 a,b and c The difference is no roll off behaviour at 100 Hz (Center) and no splitted bass (50 Hz signal) added to L and R.

Test 21 : Center Mode Check Select Center mode phantom = Center speaker �No� Select track 5 (20 Hz ... 20 kHz) : No output signals on the Center output or at least minimum -40 dB related to 1W outputs. Measure now on the Left and Right output channels : the lost Center signals are equally splitted and added to these left and right channels (- 3 dB) Test 22 : 3 CH mode control Select Front 3 stereo (Rear speaker �No�) Select track 6 (100 Hz ... 7 kHz): No output signals on the Surround output channel or at least minimum -40 dB related to 1W output. Measure now at the Left and Right output channels : the lost Surround signals are equally splitted and added to the Left and Right output channels (-3 dB) Test 23 : 2 CH mode control (stereo) Select Surround �OFF� Select track 5 : No output on Centre output channel Select track 6 : No output on Surround output channel Test 24 : Time delay control in Surround channel Principle description encoded burst signal spots (see fig. 1) 1- Tone burst 1 kHz during 1 msec with interval time at 20 msec are given at the same time to the L ; R inputs. t t (in phase 0�) 2- The next tone burst is given at the same time to the L R input, but in reverse phase to the R input (180�). t t t These 2 tone bursts are repeated continuously during 2 minutes. Principle description decoded signal spots in Center/Surround channel - In case of 20 msec time delay mode the results are shown in fig. 1 in Center and Surround channel. The center spots in Center channel can be used as ìMarkerî spots (trigger signal) � repeated every 40 msec. The delayed surround spots occur at the same time as the center spots (markers) - When time delay mode is changed to 15 msec the delayed surround spots move to the left with respect to the centre mark spots. - When time delay mode is changed to 25 msec or 30 msec the delayed surround spots move to the right with respect to the center spots. - In case of no time delay ! (faulty condition) the surround spots fall just between 2 center markers spots (20 msec) How to check with a double beam scope WARNING: Be sure that the ground connection (-) of each instrument is not connecteded with the safety earth � connection. To avoid damage to output amplifiers (balance type) Use only cinch (input) ground connection Select Pro Logic size �LARGE� or �SMALL� (phantom in case of no Center output.) Select 20 msec time delay in Surround channel. Adjust scope at 5 msec/division and trigger at A input Connect input A to Center channel (or L or R in case of phantom mode) Connect input B to Surround channel Adjust trigger level and the X position to set pulse A in the middle of the scope . see fig.2 (if L or R used in phantom mode choose the largest (amplitude) pulse. see fig 3 Select track 24: Pulse A = 20 msec marker Pulse B = delayed surround signal pulse marker = A (adjust with X position) marker = A

A B

A B

20msec time delay
Fig 2 Fig 3

20msec in case of phantom mode