MS-1771 User Guide. Caution! Hazardous voltages are present inside amplifier components. Caution! The MS-1771 can produce high sound pressure levels.

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1 1 MS-1771 MS-1771 User Guide MS-1771W The MS-1771 is a high powered bi-amped rotary speaker system deigned for use with console Organs. Modern technology is used in both electronic and mechanical design providing a maintenance free reliable rotary speaker system. All critical screws are threaded into steel inserts for strength and tightness. The Polymaric proprietary polymer finish is extremely rugged and appropriate if some physical contact is likely. Clean as needed with mild soap and water. Wood models should be cared for like fine furniture. Use light cleaners and quality polish. Wood finish models are less tolerant of physical damage. The power supply, motor drivers, and audio power amplifiers are on a single main chassis PC board. Once the MS-1771 has been installed and tonally adjusted, general cleaning and care of the cabinet is all that is required for long term trouble free operation. Caution! Hazardous voltages are present inside amplifier components. Caution! The MS-1771 can produce high sound pressure levels. Connection to Organ Connect the MS-1771 and the Organ to the same AC outlet if at all possible. Some buildings have wiring problems with grounds and polarity that can cause hum or even damage to the MS If you are unsure of your buildings wiring have a technician test power and grounds before you connect the MS Do not change any settings on the MS-1771 without reading the information below. The MS-1771 supports the industry standard 11 pin cable connection to an 11 pin compatible Organ. With the Organ off and the MS-1771 standby power switch off connect the 11 pin cable between the Organ and MS Plug the MS into rated AC power and turn the standby switch on. The upper LED on the amplifier chassis will illuminate. Turn the Organ on, the lower LED also illuminates indicating the MS-1771 is on and ready. Play some music with the Organ volume at about 25% noting the sound level. As all Organs are different you can adjust the volume and tone as indicated below to suit the venue. We strongly recommend that a trusted listener help during any tonal adjustments.

2 2 Default Internal Adjustments (On PC Board) Default External Adjustments (On Amplifier Chassis Rear) Amplifier tone control adjustments The amplifier chassis on the lower rear of the MS-1771 has external controls for Volume, Bass, and Treble. They are adjusted with a small blade type screwdriver. The MS-1771 is initially set up for typical installations. There are also internal EQ adjustments for acoustic and personal taste refinement. Have the Organist/Music director present when making EQ adjustments. (Internal adjustments are on the PC board, remove lower wood panel for access) 1. The volume trim control (external) should be set with the Organ played at full registration and full volume. Do not turn the volume control past any sign of distortion. 2. The horn balance: (internal) Adjusts the horn volume in relation to the 15 speaker providing overall cabinet tone and midrange balance. Use full registrations when making this adjustment. Some installations will require higher horn levels than others. 3. Treble Control: (external) Adjusts the very highest (>3 KHz) response of the cabinet and effects key click and brilliance. 4. Bass: (<150 Hz) (external) the lower pedal notes are effected. Play the Organ with full registration and low pedal notes while listening in several locations in the room. 5. High Cut: (internal) Some Organs may have to much shrill brilliance, the high cut, in conjuction with the treble control, can help tame an overly bright sound. Set the treble control first then experiment with the high cut. You may have to go back and forth a few times to finalize the sound. Rotary Speed Control Adjustments (On PC Board) All rotor and horn dynamics (internal) have been carefully set at the time of manufacture and should not need adjustment unless belt tension is changed or a belt is replaced. Of course, speeds can be changed to personal preference. Record trim control settings in case you want to return to default. There are two sets of trim controls (4 each), one set for the horn, the other set for the low rotor; Fast speed, Slow speed, Acceleration time, and Deceleration time. Horn diaphragm replacement. The horn rotates on sealed ball bearings, no oil or maintenance is required. Warning! Use a Motion Sound MS-1.2 or certified 8-ohm replacement only. 1. Remove the top rear cabinet cover screws and cover to gain access to the rotary assembly. 2. Remove the top axle shaft top support screws (See image below). 3. Remove the four screws holding the horn driver rotary assembly to the cabinet. 4. Carefully slide the assembly out the rear of the cabinet then remove the speaker wires (note polarity) from diaphragm. 5. Undo the three phillips screws to remove the diaphragm, follow the replacement s instruction sheet, then reassemble.

3 3. 15 speaker replacement 1. Remove the center rear cabinet cover. 2. Remove the two speaker wires (note polarity). 3. Remove the speaker mounting screws and lift the speaker up about 1 and then remove it from the cabinet. 4. Replace with an approved 8-ohm speaker only. (Factory speaker is an Eminence Delta 15LF 8 Ohm). Low Rotor System and belt adjustment/replacement. The low rotor rotates on sealed ball bearings, no oil or maintenance is required. 1. To tighten the belt, remove the center rear cabinet cover. 2. Loosen the two screws holding the motor assembly to the cabinet. 3. Slide the motor slightly away form the speaker, just enough to stop any belt noise. 4. Do not over tighten the belt, motor damage may occur. 5. Slow speed re-adjustment may be necessary after belt re tensioning. 6. Re tighten the motor screws.

4 4 Low Rotor Belt Replacement 1. Remove the center and lower rear cabinet covers. 2. Remove the 15 speaker wires (note polarity) and remove the speaker. 3. Loosen the lower axle shaft set screw (see image). 4. Before the shaft is moved, note a few O rings on the shaft between the rotor top and the speaker shelf. 5. Tilt the MS-1771 towards the right to allow the axle shaft to slide down through the hole in the cabinet bottom. 6. Slide the Axle down just far enough to remove the O rings and allow a new belt to slip over the rotor top. 7. Use a small screwdriver through the top axle hole to hold the O rings in place as the axle is pushed up into the top large O ring bushing. 8. Re-tighten the lower axle support set screw. Power Supply and remote turn on The MS-1771 supports the 11-pin rotary connector standard including Organ console power on. A standby/off switch on the rear of the amplifier chassis enables (On) the standby power control relay in the MS When the organ console is turned on, a transistor in the Organ console turns on the standby relay powering up the MS If the standby power switch on the MS-1771 is off, the amplifier will not power up from the Organ console. Two LED s indicate system power status by displaying standby and On condition. Upper LED = Standby on Lower LED = Power on. External Volume, Bass and Treble Control PC board. 1. Note ribbon cable polarity and then remove. The connector may be held in place by a small amount of silicone rubber. 2. Remove the mounting screws. 3. The tone control board contains the Bass, Treble and Volume external controls.

5 5 Main Power Amplifier and Motor Drive PC board. The Amplifier chassis is located in the bottom right side of the cabinet (rear view). The power amplifier board contains Motor power drivers, audio amplifiers, and DC power supplies. Some Transistors require 1 or more thermal/electric isolators. The power amplifier IC s require heat sink compound. Some models require the fan to beunsoldered from the PC board. Note polarity and location of wires. All circuits are on this single PC board. 1. Turn the MS-1771 (looking at the cabinet from the rear) on its right side. 2. Remove the two screws just above the rear top of the chassis. 3. Remove the cabinet lower back cover. 4. Remove the 5 screws from the bottom of the cabinet (they go up into the amplifier chassis). 5. Note polarity and unplug the horn and low rotor connectors. 6. If you remove the PC board make careful note of transistor heat sink insulators ATTENTION! If you intend on moving the MS-1771, leave the MDF sheet attached to the cabinet bottom or replace the MDF sheet with plywood to help prevent cabinet damage. Model MS-1771 Specifications General Remote standby on switch. Zero maintenance ball bearings on rotary horn and low rotor. Rotary horn diffuser 11 pin industry standard input connection. Audio Parameters Input signal range -- 7 Volts RMS minimum to 17 Volts RMS maximum. 200 watts bi-amped (130 wattsl Low rotor, 70 watts horn Active crossover 800Hz 18 db/oct. Rotor Controls Speakers Dimensions Independent horn and low rotor dynamic controls include; Fast and Slow terminal speeds, Ramp up time, and ramp down time. DC motor control design. Horn Driver rated 80 watts RMS with replaceable Motion Sound MS Ohm diaphragm. Low Rotor 15 Eminence Delta 15LF 8 Ohms. H 35.5 W 27.5 D 26 W 120 Lbs. Power USA 120 VAC 400 Watts Europe VAC 400 Watts Fuse in AC inlet Module Salt lake City UT. USA