M3_Calibration 电路图.pdf

M3 MIXER CALffiRATION PROCEDURE. The test signal is always a 1kHz Sinewave, default level is OdBu. Start test with all push buttons out on the front and rear of the unit, Gains pots in mid-position, faders set to 0 point. I. POWER SUPPLY WARNING! HIGH VOLTAGES EXIST ON THE PCB. To verify these voltages the PSU top cover must be removed. Check the following voltages while the PSU is connected to the M3. V+ = + 15. 75vdc:i: O.lvdc, adjust via RVI on PC180. V- = -15.75vdc:i: O.lvdc, adjust via RV2 on PC180. HT = 2lOvdc:i: 5vdc, adjust via RV3 on PC180. Phantom Power = +48vdc:i: Ivdc, adjust using RV4 on PCI80 +5V = 5.Ovdc :!:D.3vdc. Note: DO NOT SET mESE POTS WHn.E THE M3 IS NOT CONNECTED TO THE PSU. 2. BALANCE Connect a signal to Channell LINE input and check the + & - outputs on the DIRECT OUT jack socket are about the same amplitude. (RV9) Repeat this for all Modules. (RV9) Repeat for Master section Left & Right XLR outputs. (RVI / RV2) Repeat for Master section MONITOR outputs. (RV4 / RV6) Repeat for Master section AUX outputs. (RVI / RV3) Note: TO ADJUST THE BALANCE REQUIRES REMOVAL OF mE REAR PANEL AND SHOULD ONLY BE CARRIED OUT AS A MATTER OF NECESSITY AND NOT PART OF ROUTINE CALmRAllON. 3. MODULE GAIN Connect a signal to Channell LINE input socket. (0 dBu) Connect Output to Channel DIRECT OUT socket. Set Channell fader to maximum and vary the + lOdE trim pot at the rear of the Module for +10 dBu :!:D.ldBu. Set Channell fader to line up with the 0 position on fader scale and vary the OdE trim pot at the rear of the Module for 0.0 dBu :!:D. I dEu. Repeat for Channels 2 to 8. 4. MASTER GAIN Connect a signal to Channell LINE input socket. (0 dBu) Connect Output to Master LEFf /RIGHT XLR Outputs as instructed. Set Master Fader to maximum and measure Output on Left XLR, vary L+ lOdE trim pot at the rear of the Master panel for +10 dBu :!:D. I dBu. Set Master Fader to 0 position on fader scale and vary L OdE trim pot at the rear of the Master panel for 0.0 dBu:i: 0.1 dBu. Repeat by using Right XLR output and Right trim pots. 5. METER CAL Change the input level to +4 dBu, still using Channel I. Verify that the Left & Right XLR outputs read +4.0 dBu, if not adjust the Master fader. Adjust METER L & METER R rear panel trim pots so the Left and Right Meters read OVU. 6. PFL GAIN While viewing the Left & Right Meters press Channell PFL button, check for less than 0.3 dB change in meter reading. If an error needs to be corrected then RV9 and RVIO will require adjustment on PC 178. As this requires removal of the rear panel it should only be undertaken when absolutely necessary. THIS PROCEDURE IS INTENDED FOR USE BY A QUALIFIED TECHNICIAN ONLY. WARNING! HIGH VOLTAGES CAN EXIST ON THE PCBs. m3_cal.doc 30-Aug-2001 Sonic Touch Ltd RadioFans.CN 收音机爱 好者资料库