SERVICE MANUAL PDM- Stereo Preamp Mixer CONTENT S: Connections & Operations:...Page - Specifications:...Page Parts Lists:...Page - PCBs:...Page - Schematics:...Page - Gemini Sound Products Corp. 0 Clover Place P.O. Box Edison, NJ 0- --00 (Phone) --00 (Fax) Page
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Connections. Before plugging in the power cord, make sure that the VOLTAGE SELECTOR () switch is set to the correct voltage. NOTE: This product is double insulated and not intended to be grounded.. Make sure that the POWER () switch is in the off position. The POWER () will be off.. The PDM- is supplied with sets of amp output jacks. The MAIN OUTPUT () jacks are unbalanced and used to connect to your main amplifier. The REC OUTPUT () jacks can be used to connect the mixer to the record input of your recorder enabling you to record your mix. The BOOTH OUTPUT (0) jacks allow you to hook up an additional amplifier.. For your convenience, there are inputs for the mic. The MIC () input (found on the front panel) accepts an XLR connector. The MIC () input (found on the rear panel) accepts /" connectors. All accept balanced and unbalanced microphones.. On the rear panel are stereo PHONO/LINE (,, ) inputs and stereo LINE (,,, 0, ) inputs. The PHONO/LINE SWITCH () enables you to set the () input to Phono or Line. The PHONO/ LINE SWITCH () enables you to set the () input to Phono or Line. The PHONO/LINE SWITCH () enables you to set the () input to Phono or Line. The phono inputs will accept only turntables with a magnetic cartridge. A GROUND SCREW () for you to ground your turntables is located on the rear panel. The stereo line inputs will accept any line level input such as a CD player, a cassette player, etc.. Headphones can be plugged into the front panel mounted HEADPHONE () jack.. CHANNEL : Switch # () allows you to select the PHONO /LINE () or the LINE () input. The CHANNEL SLIDE () controls the input level of this channel.. CHANNEL : Switch # () allows you to select the LINE () or the LINE () input. The CHANNEL SLIDE () controls the input level of this channel.. CROSSFADER SECTION: The CROSSFADER () allows the mixing of one source into another. The PDM- features an assignable crossfader. The ASSIGN (, ) switches allow you to select which channel will play through each side of the crossfader. The ASSIGN () switch has settings (OFF,,, or ) and allows you to select channel,, or to play through the left side of the crossfader. The ASSIGN () switch has settings (OFF,,, or ) and allows you to select channel,, or to play through the right side of the crossfader. With the ASSIGN switch in the off position, that side of the crossfader will be inactive. The CROSSFADER () in your unit is removable and if the need arises can be easily replaced. Crossfader units are available in three varieties. Part # RF- (which is identical to the crossfader supplied with the mixer) has a mm travel from side to side. Part # RF-0 is available with a 0 mm travel distance. Also available is the PSF- with a special curve designed for scratch mixing. Just purchase one of these crossfader units from your Gemini dealer and follow these instructions:. Unscrew the outside FADER PLATE SCREWS (B). Do not touch the INSIDE SCREWS (C).. Carefully lift the fader and unplug the CABLE (D).. Plug the new fader into the cable and place it back in the mixer.. Screw the fader to the mixer. Using the Ground Lift Switch Depending on your system configuration, sometimes applying the ground will create a quieter signal path. Sometimes lifting the ground can eliminate ground loops and hum to create a quieter signal path.. With the mixer on, listen to the system in idle mode (no signal present) with the ground applied (the GROUND LIFT SWITCH () in the left position).. Then turn the power off before moving the GROUND LIFT SWITCH (). Lift the ground by moving the GROUND LIFT SWITCH to the right, turn the power back on and listen to determine which position will provide a signal devoid of background noise and hum. Keep the GROUND LIFT SWITCH in the ground position if the noise level remains the same in either position. CAUTION: DO NOT TERMINATE THE AC GROUND ON THE POWER MIXER IN ANY WAY. TERMINATION OF THE AC GROUND CAN BE HAZARDOUS. Operation. POWER ON: Once you have made all the equipment connections to your mixer, press the POWER SWITCH (). The power will turn on and the POWER () will glow RED.. CHANNEL : Switch # () allows you to select the PHONO /LINE () or the LINE () input. The CHANNEL SLIDE () controls the input level of this channel.. CHANNEL : Switch # () allows you to select the PHONO /LINE () or the LINE (0) input. The CHANNEL SLIDE () controls the input level of this channel.. OUTPUT CONTROL SECTION: The level of the MAIN AMP OUT () is controlled by the MASTER () slide. The Master TREBLE (0) and BASS () controls allow you to adjust the output of channels -. The BOOTH () control adjusts the level of the BOOTH OUTPUT (0). HINT: The booth output is used by some DJs to run monitor speakers in their DJ booth. You can also use it as a second ZONE or AMP output. NOTE: The RECORD OUT () has no level control. The level is set by the channel slides of the selected channel.. TALKOVER SECTION: The purpose of the talkover section is to allow the program playing to be muted so that the mic can be heard above the music. The MIC/TALKOVER SWITCH () has three settings. When the MIC/TALKOVER SWITCH () is in the bottom position, the mic and talkover are both off. When the MIC/TALKOVER SWITCH () is in the center position the mic is on, the MIC INDICATOR () will glow, but talkover is off. When the MIC/TALKOVER SWITCH () is in the top position, the mic and talkover will be on and the volume of all sources except the Mic input are lowered by db. The TREBLE () and BASS () controls allow you to fully adjust the tone of the MIC. LEVEL () controls the level of the MIC. Page
. CUE SECTION: By connecting a set of headphones to the HEADPHONE () jack, you can monitor any or all of the channels. Press the CUE ASSIGN () buttons for channels - to select the channel or channels to be monitored and their respective indicators will glow. Use the CUE LEVEL () control to adjust the cue volume without effecting the overall mix. By moving the CUE PGM PAN () control to the left you will be able to monitor the assigned cue signal. Moving the control to the right will monitor the PGM (program) output. Rotating to the right will monitor the PGM (program) output.. DISPLAY: The DISPLAY () indicates the MASTER output left and right levels. Specifications INPUTS: DJ Mic...mV Kohm balanced Phono...mV Kohm Line...0 mv Kohm OUTPUTS: Amp/Booth...0 db V 00ohm Max...0V Peak to Peak Rec...mV Kohm MIC: DJ Mic...mV Kohm balanced Bass...± db High...± db GENERAL: Frequency Response...0Hz - 0KHz +/- db Distortion...0.0% S/N Ratio...better than 0dB Parts Lists 0 0 Cabinet Parts and Packing Description Part # PANEL CONTROL PANEL REAR COVER BOTTOM BRACKET VR HOLDER X-FADER PROTECTOR PLATE FOR /0V SWITCH SWING LEVEL KNOB PUSH (SMALL) BUSHING FOR KNOB (SMALL) KNOB SLIDE (SMALL) KNOB SLIDE (BIG) KNOB ROTARY (ASSIGN) KNOB ROTARY (B) KNOB INLAY (BLACK); LEVEL,BALANCE,CUE KNOB INLAY (GRAY); TREBLE,BASS TRIM VR HOLDER f (mm) WASHER XLR PAD FOOT DUST PROOF CLOTH (VR) DUST PROOF CLOTH (KNOB-SWING) DUST PROOF CLOTH (VR) GND SCREW PAN-HEAD MACHINE SCREW; PMS X(B) PAN-HEAD MACHINE SCREW; PMS.X(B) BAND-HEAD TAPPING SCREW/TWIN SCREW; BTS- X(AB) TWIN FLAT-HEAD TAPPING SCREW; FTS- X(AB) BAND-HEAD TAPPING SCREW; BTS- X(AB) BAND-HEAD TAPPING SCREW; BTS- X(AB) FLAT-HEAD TAPPING SCREW; FTS- X(AB) FLAT-HEAD TAPPING SCREW; FTS- X(Y) BAND-HEAD TAPPING SCREW; BTS- X(AB) BAND-HEAD TAPPING SCREW/TW-E; BTS-/ TW-E X(AB) NUT/WASHER mm 00-0 0-0-0 0-0- 0-0 0-00- 00-00-0 00-0 00-00- - - 00-0 00-00- 0-0 - - - - -00-0 -A -0A -0A -0A -0A -00-0A -0A -0 Talkover Attenuation...-dB Headphone Impedance...ohm Power Source.../0V 0/0Hz W Dimensions... w x h x d Weight... lbs Printed Circuit Boards Description Part # PRINTED CIRCUIT BOARD PDM-: SWITCH (V0 ) PRINTED CIRCUIT BOARD PDM-: MAIN PRINTED CIRCUIT BOARD PDM-: MASTER VR PRINTED CIRCUIT BOARD PDM-: FADER (V0. ) PRINTED CIRCUIT BOARD PDM-: PHONES (V0. ) -0-00 -0-0 -0 Page
Parts Lists - PCB,, IC IC- ICs INTEGRATED CIRCUIT NJMLD INTEGRATED CIRCUIT NJM0LD 0-0- Diodes D- LIGHT EMITTING DIODE (RED).f 00-0 J J- SW,, SW,,, SW SW, SW,,, VR- X-FADER VR- VR Electrical Parts PHONE JACK.f P RCA JACK P=mm SLIDE SWITCH PC LEVER SW PC LEVER SW PC ROTARY SWITCH -- L= FAD ASSIGN PUSH SWITCH PC L=. SLIDE VR mm L=0 CH VOL MASTER 0KA SLIDE VR mm L=0 FADER 0KB ROTARY VR f L=0 MIC-TONE 0KA C.C ROTARY VR f L=0 MIC VOL 0KA 0-0 - 0-00 0-0 0-0 0-0 0-0 0-0 0-0 0-0- Parts Lists - PCB, IC, IC, IC IC IC IC,,, IC IC Q- Q ICs INTEGRATED CIRCUIT NJMLD INTEGRATED CIRCUIT NJML INTEGRATED CIRCUIT NJM0LD INTEGRATED CIRCUIT LB0N INTEGRATED CIRCUIT NJMFA INTEGRATED CIRCUIT NJMFA Transistors TRANSISTOR SC TRANSISTOR SA (SA) 0-0- 0-0-0 0-0- 0-0 0- D-0 D- D-, D-D D-, D J J VR VR VR- VR, Diodes RECTIFIER DIODE N00 (N00,N00) SILICON DIODE N LIGHT EMITTING DIODE (GREEN).f LIGHT EMITTING DIODE (YELLOW).f LIGHT EMITTING DIODE (RED).f Electrical Parts PHONE JACK.f P RCA JACK P=mm SLIDE VR mm L=0 CH VOL MASTER 0KA SLIDE VR 0mm L= CUE FADER 0KB ROTARY VR f L=0 CH-TONE 0KW CC ROTARY VR f L=0 BOOTH CUE VOL 0KA 0-0 0-00 00-00- 00-0 0-0 - 0-0 0-0 0-0-0 Page
ICA 0LD ICB 0LD R 0K R R R K R 0 R K R K R K R 0 R 0K C C C C C C0 C / C / C / C / R K R K R R C C C C C C ICA 0LD ICB 0LD R 0K R R R K R0 0 R0 K R K R K R 0 R 0K C C C C C0 C C / C / C / C / R K R K R R C C C C C C0 ICA 0LD ICB 0LD R 0K R R R K R 0 R0 K R K R K R 0 R0 0K C C C C C C C / C / C0 / C / R K R K R R C C C C C0 C R R0 R R R R R R C C C C R R C C C C L R G J J J J J J J J VRA 0KAX VRB 0KAX R R R R C SWA SWC SWD SWB R0 R R R D VRA 0KAX VRB 0KAX R SWA SWB SWA SWB SWC SWD R R0 R0 R VRA 0KAX C0 R R R R D R SWA SWB VRB 0KAX VRA 0KAX R R R R R R R R D R SWA SWB VRB 0KAX R R R R R0 R R R D R SWA SWB L R L R L R L R X X X SWA SWC SWD SWB SWA SWC SWD SWB ICA LD ICB LD R R R 0K % C C C / C / C C C R K % R K % R 0K % T R S J VR 0KA VR 0KA C C C C R R 0 R K VR 0KA C.P SWC SWD SW0* R D SWA SW-0WAY* SWB SW-0WAY* SWA SW-0WAY* SWB SW-0WAY* L L L L R R R R L L L L R R R R R 0K R R C C C C R K R 0K C C R K SWB SW0* SWA SW0* ICA 0LD ICB 0LD R K R R C C C C 0/ C 0/ C0 R K C 0/ C 0/ ICA 0LD ICB 0LD C SWA SWB X SWA SWB X SWA SWB X X-FADER LN PH/LN LN PH/LN LN PH/LN LN LN MIC MIC XLR X X X + G - XLR XLR X R 0K RA 0 Page PCB,, - Schematic
J J R0 0K R K R 0 C0 C C C R R VRA 0KAX R K R R R R R C C C C VRA 0KWX VRB 0KWX ICA LD C C C R K R R R C C C C A A A VRA 0KWX B B B VRB 0KWX ICB LD C R K R K VRB 0KAX R 0K R K R 0 C C VRB 0KAX ICA R 0K R K R 0 C0 C C C R R0 VRA 0KAX ICB R 0K R K R 0 C C R K R K IC LB0N IC LB0N IC LB0N IC LB0N D D D D D D D D0 D D D D D D D D D D D D R K R 0K R0 0K R 0K R K R K R K R 0K R 0K R 0K R K R K C C./ C C C0./ C R R R R R C R 00 R0 0 R K L R G J C C R K R0 K R K R R ICA C C C C R K R K ICB C C0 R K VRB 0KBX VRA 0KBX VRA 0KA VRB 0KA ICA ICB R 0K R 0K R K R R K C./ C./ C 0/ C 0/ C C R R C R R0 R C C X PLUG0 C C Q SC Q SA D N R 0K D N C 0/ C,/ R K C R 00 R 0 R K Q SC R K C R 00 R 0 R K Q SC C R 00 R 0 R0 K Q SC R0 K ML MR MR ML ICB 0LD ICA 0LD C C 0/ C 0/ C C / C0 / X D N00 D N00 D N00 D N00 C D0 N00 IC IC C 0/ +MET D R +MET R C 0/ C0 0/ R M X X X SOCKET0 T R S J Page PCB, - Schematic